JPH0965253A - Image display device - Google Patents

Abstract

(57) [Summary] (Correction) [Problem] A reproduction two-screen image having a different number of line periods in each frame period is subjected to time-axis compression processing for each line period, and there is substantially no deleted portion. To get SOLUTION: Two video signal input terminals 10 and 11, and
The line memory unit 15 performs time-axis compression for each line period of the first video signal, and the time-axis compression for each line period of each of the odd field period and the even field period of the second video signal. The frame memory unit 16, the line memory unit 15, and the frame memory unit 16 that are performed
Signal selection unit 2 which forms a display video signal from the output signal of
5 and two video signals supplied to the input terminal have different number of line periods included in each frame period,
The display video signal obtained from the signal selection unit 25 is always
A signal transmission control unit 12, 21, 23 for controlling the transmission state of two video signals so that the one having the largest number of line periods included in each frame period is used as a reference.
With.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for displaying an image represented by each of two independent video signals as a two-screen image on the display surface of one image display section.

[0002]

2. Description of the Related Art A dual-screen image display system for displaying an image represented by each of two independent video signals on its image display surface using a single image display device is part of the diversification of image information provision. Is proposed as. In such a two-screen image display system, for example, an image display device having an image display surface on which horizontal scanning (line scanning) and vertical scanning (field scanning) are performed is used. A screen of an image represented by each of the two video signals is formed on the surface as being arranged adjacent to each other in the line scanning direction, that is, in the left-right direction.

In this way, when displaying a two-screen image in which two screens are arranged adjacent to each other in the left-right direction on the image display surface of the image display device, for example, the dimension of each of the two screens in the line scanning direction is substantially. Therefore, the image represented by the first video signal, which is one of the two video signals, is displayed on the left half of the image display surface, and the two video signals are displayed on the right half of the image display surface. Assuming that the image represented by the second video signal, which is the other one of the above, is displayed, the display video signal supplied to the image display device includes each line period corresponding to one line period of the first video signal ( 1H) time-axis compressed to approximately 1/2 line period (0.5 H) time-axis compressed 1-line period of the second video signal and time-axis compressed to approximately 1/2 line period Combine with video signal It is required to be formed and formed.

In order to obtain such a video signal for dual-screen image display, for example, a line memory capable of writing and reading for one line period of the video signal is used, and the first video signal By processing so that the line period portion is time-axis compressed to approximately ½ line period, a first time-axis compressed video signal is obtained, and one field period (1V) portion of the video signal is two (odd number). By using a frame memory capable of writing and reading for one frame period (2V) which is continuously formed by the field period and the even field period), the second video signal is supplied for each frame period. A second time-axis compressed video signal is obtained by processing so that each line period is time-axis compressed into approximately 1/2 line period, and the first time-axis compressed video signal and the second time-axis compressed video signal are obtained. Compressed video signal A method of synthesis is taken at the door.

To obtain the first time-axis compressed video signal, the first video signal is sequentially written into the line memory for each line period, and the written video signal for each line period is written from the line memory. Reading is performed with a read time corresponding to approximately 1/2 line period, and the read time is set so that its start time coincides with the end time of the write time for one line period of the first video signal, for example. Select. That is, FIG. 8 (horizontal axis: time, vertical axis:
Line memory address), each line period portion of the first video signal is sequentially written in the line memory as indicated by a broken line, and each line period portion is written as indicated by a solid line in FIG. Is read. The reading for each line period shown by the solid line in FIG. 8 is started at the time when the writing for the line period is completed, and is performed at a speed approximately twice the writing speed, and substantially for the line period. Is completed in about 1/2 line period after the completion of the entire writing of. Therefore, the reading of each line period from the line memory is intermittently performed with a time period corresponding to approximately 1/2 line period and an interval corresponding to approximately 1/2 line period. As a result, the first time-base compressed video signal is obtained from the line memory.

To obtain the second time-axis compressed video signal, the odd field period and the even field period forming each frame period of the second video signal are sequentially written in the frame memory. Then, the video signal for each line period included in each frame period of the second video signal written therein is read from the frame memory with a read time corresponding to approximately 1/2 line period. Thereby, from the frame memory, the second
The time-axis compressed video signal for each frame period of the video signal is obtained as the second time-axis compressed video signal.

The first time-axis compressed video signal obtained from the line memory and the second time-axis compressed video signal obtained from the frame memory
The time-axis compressed video signal of, for example, each 1/2 line period of the first time-axis compressed video signal is connected to each 1/2 line period of the second time-axis compressed video signal. Are combined so that each line period is formed. As a result, the first half of each line period is the first time-axis compressed video signal based on the first video signal, and the second half is the second time-axis compressed video signal based on the second video signal. And a video signal for displaying a two-screen image is formed.

Under the circumstances, since the first video signal and the second video signal are independent of each other and are not in the mutually synchronized state, the first video signal and the second video signal are not synchronized with each other. A problem is the synchronization state between the first time-axis compressed video signal and the second time-axis compressed video signal. So, for example, the first
The writing of the video signal of
Is performed according to the timing signal formed based on the synchronization signal included in the second video signal, and the writing of the second video signal to the frame memory is performed based on the synchronization signal included in the second video signal. Read out from the line memory for each line period, and each line included in each frame period of the second video signal from the frame memory. The reading for each period is performed according to the timing signal formed based on the synchronization signal included in the first video signal, and the first time-axis compressed video signal obtained from the line memory is used. The second time-base compressed video signal obtained from the frame memory is placed in mutual synchronization. That is, the two-screen image display video signal is formed with reference to the first video signal.

In this way, when the two-screen image display video signal is formed, the writing of the second video signal to the memory portion is performed based on the synchronization signal included in the second video signal. Timing signal generated based on a synchronization signal included in the first video signal which is not in mutual synchronization with the second video signal, and which is read out from the memory section for each line period. The frame memory is used for writing and reading the second video signal.

[0010]

When the two-screen image display video signal is formed as described above, the number of line periods in which the first video signal and the second video signal are included in each frame period. If they are different, the number of horizontal scanning lines forming the reproduced screen image based on each frame period is different from each other. Therefore, a two-screen image obtained by supplying the two-screen image display video signal obtained from them to an image display unit having an image display surface on which line scanning and field scanning are performed is the same as the first video signal. It is affected by the difference in the number of line periods included in each frame period from the second video signal, that is, the difference in the number of horizontal scanning lines forming a reproduced screen image based on each frame period.

For example, the first video signal or the second video signal is a color video signal (NT
SC video signal, and the second video signal or the first video signal is a color video signal (PA
L video signal), the NTSC video signal has 525 line periods included in each frame period, while the PAL video signal has 625 line period numbers included in each frame period. Therefore, the number of horizontal scanning lines forming a reproduction screen image based on each frame period of the PAL video signal is larger than the number of horizontal scanning lines forming a reproduction screen image based on each frame period of the NTSC video signal.
Therefore, the two-screen image obtained by supplying the two-screen image display video signal obtained from the NTSC video signal and the PAL video signal to the image display unit is a horizontal scanning line forming an image represented by the NTSC video signal. The number of them is smaller than the number of horizontal scanning lines forming an image represented by the PAL video signal.

Therefore, in the image display unit, the number of line periods included in each frame period of the video signal as the first video signal is included in each frame period of the video signal as the second video signal. If the first video signal is a PAL video signal and the second video signal is an NTSC video signal,
Since the two-screen image display video signal obtained from them is formed on the basis of the PAL video signal which is the first video signal, the image represented by the PAL video signal is displayed on the image display surface as a whole, and An image represented by an NTSC video signal having a smaller number of horizontal scanning lines than that is displayed, for example, in a state accompanied by an image mute portion in which image display is not performed above and below. FIG. 9 shows an image (P) represented by a PAL video signal on the left side of the two screens divided by the vertical line image mute section XM on the image display surface of the image display section, and an NTSC video signal on the right side. The state where the image (N) shown is displayed is shown. In FIG. 9, the image (P) represented by the PAL video signal is displayed with 580 horizontal scanning lines.
The image (N) represented by the C video signal has 490 horizontal scanning lines.
The book is displayed with a book, and the image mute section ZM is provided above and below the book.

On the other hand, the number of line periods included in each frame period of the first video signal is greater than the number of line periods included in each frame period of the second video signal. If less, for example,
When the first video signal is an NTSC video signal and the second video signal is a PAL video signal, the NTSC video signal whose dual-screen image display video signal obtained from them is the first video signal is Since it is formed as a reference, the image represented by the NTSC video signal is entirely displayed on the image display surface of the image display unit, and the image represented by the PAL video signal having more horizontal scanning lines than that is displayed, for example, The upper portion and the lower portion are displayed in a deleted state without being displayed as an image. FIG.
Is the NTSC on the left side of the image display surface of the image display unit.
The image (N) represented by the video signal is displayed, and PA is displayed on the right side.
The state where the image (P) represented by the L video signal is displayed is shown. In FIG. 10, the image (N) represented by the NTSC video signal is displayed with 490 horizontal scanning lines, and the image (P) represented by the PAL video signal is originally displayed with 580 horizontal scanning lines. Where it should be, the upper and lower parts should be horizontal scanning lines 90
The number of lines is deleted, and the number of horizontal scanning lines is displayed as 490.

As described above, when the two-screen image based on the two-screen image display video signal is displayed on the image display unit, the line period included in each frame period in the video signal which is the first video signal. When the number is smaller than the number of line periods included in each frame period in the video signal that is the second video signal, the two-screen image obtained in the image display unit is the image represented by the second video signal. , The upper part or the lower part, or both the upper part and the lower part are deleted. It is difficult to say that the image display performed with such a partially deleted state is satisfactory, and the user of the image display device is dissatisfied, or
You will have a strange feeling.

As a measure for avoiding a situation in which an image is partially missing in such a two-screen image display,
A process of converting the number of line periods included in each frame period is performed on one of the first and second video signals representing the two images in the dual-screen image display, and the one of the first and second video signals is converted. It is conceivable to match the number of line periods included in each of the other frame periods. However, when such a measure is taken, there is a problem that the circuit configuration for performing the process of converting the number of line periods included in each frame period of the video signal becomes large and costly. There is also a problem that an image displayed based on a video signal in which the number of line periods included in each frame period is converted is accompanied by deterioration in image quality.

In view of the above point, according to the present invention, by using the line memory section, the first video signal is time-axis-compressed for each line period into about 1/2 line period. The first time-axis compressed video signal is obtained and
2) by using the frame memory unit under the condition that the reference timing is set with the synchronization signal included in the video signal of
Of the first time axis by obtaining the second time axis compressed video signal by using the video signal When the two-screen image display video signal is obtained by synthesizing the compressed video signal and the second time-axis compressed video signal, the two video signals, which are the first video signal and the second video signal, respectively, are obtained. When the number of line periods included in each frame period is different, a two-screen image display video signal formed on the basis of the two video signals is generated on the basis of both of the two-screen images displayed by the image display unit. There is provided an image display device capable of preventing partial deletion.

[0017]

An image display device according to the present invention includes first and second video signal input ends to which two video signals, which are first and second video signals, are supplied. First
A line memory unit for sequentially and intermittently obtaining a video signal for a first 1/2 line period, which is formed by performing time-axis compression reading for each line period of the video signal of
Of the second 1/2 line period formed by performing the time-axis compression reading for the line period included in the odd field period and the even field period forming each frame period of And the third 1/2
A frame memory unit that sequentially obtains video signals for a line period, and a first 1/1 / that is obtained from the line memory unit.
A signal selection unit for alternately extracting a video signal for two line periods and a video signal for the second or third 1/2 line period obtained from the frame memory unit to form a video signal for display, and a signal selection unit. A two-screen image display unit that displays a two-screen image corresponding to the image represented by each of the first and second video signals in accordance with the display-use video signal obtained from the first and second video signals. When the two video signals supplied to the second video signal input terminal are different in the number of line periods included in each frame period, they are included in each frame period of the two video signals. A signal transmission control unit for controlling the transmission states of the two video signals is provided so that the one having a large number of line periods is always the first video signal.

In the image display device according to the present invention configured as described above, the lines included in each frame period of the video signal supplied to the first video signal input end by the signal transmission control unit. When the number of periods is larger than the number of line periods included in each frame period of the video signal supplied to the second video signal input end, the video signal supplied to the first video signal input end is the first And is supplied to the line memory unit as the second video signal, and the video signal supplied to the second video signal input end is supplied to the frame memory unit as the second video signal. The number of line periods included in each frame period of the video signal supplied to the video signal input end is smaller than the number of line periods included in each frame period of the video signal supplied to the second video signal input end. Sometimes The video signal supplied to the second video signal input end is used as the first video signal and is supplied to the line memory unit, and the video signal supplied to the first video signal input end is the second video signal. Transmission control is performed for the two video signals supplied to the first and second video signal input ends that are to be supplied to the frame memory unit as video signals.

Accordingly, when the two video signals supplied to the first and second video signal input terminals have different numbers of line periods included in each frame period, at all times,
The one of the two video signals, which has the largest number of line periods included in each frame period, is set as the first video signal, and the time axis compression reading is performed for each line period in the line memory unit to obtain the first video signal. Of the two video signals, and the one having the smaller number of line periods included in each frame period of the two video signals is the second video signal. In the frame memory section, the time axis compression reading is performed for the line period included in the odd field period and the even field period forming each frame period, and the second half is obtained.
A video signal for the line period and a video signal for the third 1/2 line period are formed.

As a result, the video signal for the first 1/2 line period obtained from the line memory unit and the video signal for the second or third 1/2 line period obtained from the frame memory unit are supplied. The video signal for display (video signal for dual-screen image display) from the signal selection unit
That is, of the two video signals supplied to the first and second video signal input ends, the one having the larger number of line periods included in each frame period is formed as a reference. Therefore, in the two-screen image displayed by the two-screen image display unit in accordance with such a two-screen image display video signal, the first one in which the number of line periods included in each frame period is larger The image represented by the video signal is
The image represented by the second video signal, which is displayed as the one having the larger number of horizontal scanning lines forming the whole and is the one having the smaller number of the line periods included in each frame period, Will be displayed as a whole with the image mute section as the one having a smaller number of horizontal scanning lines.

As a result, when the two video signals, which are the first video signal and the second video signal, have different line period numbers included in each frame period, the two video signals are generated. The two-screen image display video signal formed on the basis of the two-screen image is based on the two-screen image displayed so that the two-screen image displayed on the image display unit is not substantially deleted.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of an image display device according to the present invention.

In the example shown in FIG. 1, two independent video signals S are provided at the video signal input terminals 10 and 11.
V1 and SV2 are supplied. At that time, the video signal SV1
Is supplied to the video signal input terminal 10 and the video signal SV2 is supplied to the video signal input terminal 11, or the video signal SV1 is supplied to the video signal input terminal 11 and the video signal SV2 is supplied to the video signal input terminal. 10 is supplied. Video signals SV1 and SV2
Is different from each other in the number of line periods included in each frame period (formed by an odd field period and an even field period), such as a PAL video signal and an NTSC video signal, and each frame period of the video signal SV1. The number of line periods included in the above is larger than the number of line periods included in each frame period of the video signal SV2.

The video signals SV1 and SV2 from the video signal input terminals 10 and 11 are supplied to the video signal selection controller 12. The video signal selection control unit 12 controls the video signal SV1.
And SV2, the video signal SV1 is supplied through the video signal input terminal 10 and the video signal input terminal 11, respectively.
The first video signal is supplied to the analog / digital conversion unit (A / D conversion unit) 13 and the video signal S
The video signal SV2 of V1 and SV2 is A / D converted as the second video signal regardless of whether it is supplied through the video signal input terminal 11 or the video signal input terminal 10. Transmission control of the video signals SV1 and SV2 to be supplied to the unit 14 is performed.

Video signal S supplied to A / D converter 13
V1 is digitized in the A / D converter 13,
The line memory unit 15 is used as the digital video signal DV1.
Is supplied to. The video signal SV2 supplied to the A / D conversion unit 14 is digitized in the A / D conversion unit 14 to be a digital video signal DV2 and supplied to the frame memory unit 16. The frame memory unit 16 is composed of a field memory unit 17 and a field memory unit 18.

Further, the video signal SV1 obtained from the video signal selection control unit 12 is supplied to the synchronization signal separating unit 19 and the video signal SV from the video signal selection control unit 12 is supplied.
2 is supplied to the synchronization signal separation unit 20. The sync signal separating unit 19 separates the horizontal sync signal (line sync signal) PH1 and the vertical sync signal (field sync signal) PV1 contained therein from the video signal SV1 and supplies them to the timing signal forming unit 21. Similarly, in the synchronizing signal separating section 20, the horizontal synchronizing signal PH2 and the vertical synchronizing signal PV2 included therein are separated from the video signal SV2 and are supplied to the timing signal forming section 22.

Further, the video signal SV1 from the video signal input terminal 10 and the video signal S from the video signal input terminal 11
Both V2, or both the video signal SV2 from the video signal input terminal 10 and the video signal SV1 from the video signal input terminal 11 are supplied to the line period number identification unit 23. In the line period number identifying unit 23, the number of line periods included in each frame period of the video signal (video signal SV1 or video signal SV2) from the video signal input terminal 10 and the video signal from the video signal input terminal 11 ( The number of line periods included in each frame period of the video signal SV2 or the video signal SV1) is identified, and the difference between the two is obtained. Then, the identification signal CM representing the obtained difference in the number of line periods is supplied from the line period number identification unit 23 to the timing signal forming unit 21.

The identification signal CM obtained from the line period number identification unit 23 is such that the number of line periods included in each frame period of the video signal from the video signal input terminal 10 is each frame period of the video signal from the video signal input terminal 11. Is greater than the number of line periods included in, that is, when the video signal SV1 is supplied to the video signal input terminal 10 and the video signal SV2 is supplied to the video signal input terminal 11, for example, the positive polarity And represents the difference between the number of line periods included in each frame period of the video signal SV1 and the number of line periods included in each frame period of the video signal SV2, and the video signal from the video signal input terminal 10 The number of line periods included in each frame period is greater than the number of line periods included in each frame period of the video signal from the video signal input terminal 11. When small, i.e., when in the state in which the video signal SV1 in a video signal input terminal 11 together with the video signal SV2 to the video signal input terminal 10 is supplied is supplied, for example, a video signal a negative SV2
The number of line periods and the video signal S included in each frame period of
The difference from the number of line periods included in each frame period of V1 is represented.

When the number of line periods included in each frame period of the video signal from the video signal input terminal 10 is equal to the number of line periods included in each frame period of the video signal from the video signal input terminal 11, that is, For example, the video signal SV1 is supplied to both the video signal input terminals 10 and 11, or the video signal input terminals 10 and 1 are supplied.
When the state in which the video signal SV2 is being supplied to both of 1 is taken, the line period number identification unit 23 outputs the identification signal C
M is not sent.

In the timing signal forming unit 21, a writing timing signal WL and a reading signal for the line memory unit 15, which are synchronized with the horizontal synchronizing signal PH1 and the vertical synchronizing signal PV1 from the synchronizing signal separating unit 19, are read. Timing signal RL, read timing signal RF for field memory unit 17, field memory unit 1
The read timing signal RF2 for 8 and the selection control signals SS, SM and SN are formed. At that time, when the identification signal CM from the line period number identification unit 23 has a positive polarity, the read timing signal RL supplied to the line memory unit 15 is the signal written from the line memory unit 15 into the read timing signal RL. Of the video signal SV1 during the first half of each line period in the video signal SV1, and the read timing signal RF1 supplied to the field memory unit 17 is Time-axis compression reading of the signal written in it from the memory unit 17
From the start of the odd field period of the video signal SV1,
It starts from a time point delayed by a time corresponding to the line period in the predetermined number of video signals SV1 corresponding to the difference in the number of line periods represented by the identification signal CM, and is approximately ½ line in the latter half of each line period in the video signal SV1. It is supposed to be performed during the period and the field memory unit 1
The read timing signal RF2 supplied to the signal line 8 indicates the time-axis compressed read of the signal written in the read signal from the field memory unit 18 from the start time of the even field period of the video signal SV1 in the line period represented by the identification signal CM. To start from a time point delayed by a time corresponding to a line period in a predetermined number of video signals SV1 corresponding to the difference in number, and to perform in approximately the latter half line period in each line period in the video signal SV1. To be done.

On the other hand, when the identification signal CM from the line period number identification section 23 has a negative polarity, the read timing signal RL supplied to the line memory section 15 is written from it to the line memory section 15. It is assumed that the time-axis compression reading of the signal is carried out in the latter half of approximately 1/2 line period in each line period of the video signal SV1, and the read timing signal RF1 supplied to the field memory unit 17 is used. , The time-axis compression reading of the signal written therein from the field memory unit 17 is performed from the start of the odd field period of the video signal SV1 by a predetermined number of video signals corresponding to the difference in the number of line periods represented by the identification signal CM. The video signal SV1 starts from a point delayed by a time corresponding to the line period of SV1. The read timing signal RF2 supplied to the field memory unit 18 is the same as the signal written in the first half line period of the line period. The time-axis compression reading is started from a time point which is delayed from the start point of the even field period of the video signal SV1 by a time period corresponding to a line period in a predetermined number of video signal SV1 corresponding to a difference in the number of line periods represented by the identification signal CM. However, it is to be performed in approximately the first half line period of each line period in the video signal SV1.

Further, in the timing signal forming section 21, when the identification signal CM from the line period number identifying section 23 has a positive polarity, the selection control signal S which takes a low level.
S and the selection control signal SM are sent out, whereas, when the identification signal CM from the line period number identification unit 23 has a negative polarity, the selection control signal SS and the selection control signal SN which take high levels are output. Is sent.

The selection control signal SS obtained from the timing signal forming section 21 is supplied to the video signal selection control section 12. When the selection control signal SS has a low level, the video signal selection control unit 12 therefore has the positive polarity of the identification signal CM from the line period number identification unit 23, and the video signal SV1 is input to the video signal input terminal 10. Is being supplied and the video signal SV2 is being supplied to the video signal input terminal 11, the video signal SV1 from the video signal input terminal 10 is supplied to the A / D converter 13 and the video signal input terminal is supplied. The video signal SV2 from the A / D converter 14
To supply. Further, when the selection control signal SS has a high level, the video signal selection control unit 12 has the negative polarity of the identification signal CM from the line period number identification unit 23, and the video signal input terminal 10 receives the video signal. The video signal SV2 is supplied and the video signal SV1 is supplied to the video signal input terminal 11.
Is being supplied, the video signal input terminal 1
The video signal SV2 from 0 is supplied to the A / D converter 14, and the video signal SV1 from the video signal input terminal 11 is supplied to the A / D converter 13.

In the timing signal forming section 22, the write timing signal WF1 and the field memory for the field memory section 17 which are supposed to be synchronized with the horizontal synchronizing signal PH2 and the vertical synchronizing signal PV2 from the synchronizing signal separating section 20. A write timing signal WF2 for the section 18 is formed. The write timing signal WF1 supplied to the field memory unit 17 is used to sequentially write the entire digital video signal DV2 into the field memory unit 17 for each odd field period, and to the field memory unit 18. The supplied write timing signal WF2 is used for the field memory unit 18
For sequentially writing the entire digital video signal DV2 for each even field period.

In the line memory section 15 to which the digital video signal DV1 from the A / D conversion section 13 is supplied,
The timing signal WL for writing and the timing signal RL for reading are supplied from the timing signal forming unit 21, the digital video signal DV1 is sequentially written for one line period according to the timing signal WL for writing, and the timing signal for reading is also used. According to RL, the written digital video signal DV1 for each line period is approximately 1
The time axis is compressed and read with a read time corresponding to a / 2 line period.

At this time, when the identification signal CM from the line period number identification unit 23 has a positive polarity, that is, the video signal SV1 is supplied to the video signal input terminal 10 and the video signal input terminal 11 is supplied. When the video signal SV2 is being supplied, the read timing signal RL
However, the read time corresponding to about 1/2 line period is set to 1 of the digital video signal DV1 whose start time is read.
It is assumed that the first half of each line period in the video signal SV1 coincides with the end time of the writing time for the line period and is approximately ½ line period. In addition, when the identification signal CM from the line period number identification unit 23 has a negative polarity, that is, the video signal SV2 is input to the video signal input terminal 10.
Is being supplied and the video signal SV1 is being supplied to the video signal input terminal 11, the read timing signal RL reads the read time corresponding to approximately 1/2 line period at the end point thereof. The half period of the latter half of each line period in the video signal SV1 coincides with the end time of the writing time for one line period of the digital video signal DV1 to be reproduced.

Therefore, in the writing and time-axis compression reading of the digital video signal DV1 in the line memory unit 15, the identification signal CM from the line period number identifying unit 23 is used.
Has a positive polarity, that is, the video signal input terminal 1
When the video signal SV1 is supplied to 0 and the video signal SV2 is supplied to the video signal input terminal 11, it is indicated by a broken line in FIG. 2 (horizontal axis: time, vertical axis: line memory address). As described above, each line period of the digital video signal DV1 is sequentially written, and as shown by the solid line in FIG. 2, each written line period is time-axis compressed and read. Done. That is, the time-axis compression reading for each line period of the digital video signal DV1 is started at the time when the entire line period is written, and is performed at a speed that is about twice the writing speed, and about 1/1 after the start. It is set to end when the two-line period has elapsed.

When the identification signal CM from the line period number identification unit 23 has a negative polarity, that is, the video signal SV2 is supplied to the video signal input terminal 10 and the video signal is input to the video signal input terminal 11. When the signal SV1 is being supplied, as shown by the broken line in FIG. 3 (horizontal axis: time, vertical axis: line memory address), each line period of the digital video signal DV1 is sequentially written and As shown by the solid line in FIG. 3, the writing is performed under the condition that each written line period is time-axis compressed and read. That is, the time-axis compression reading for each line period of the digital video signal DV1 is started at the time when about 1/2 of the line period is written, and is performed at a speed twice as fast as the writing speed. When approximately ½ line period elapses later, the writing is completed when the writing of all the line period is completed.

As a result, the time-axis compression reading for each line period from the line memory unit 15 is intermittent at intervals corresponding to approximately 1/2 line period, at intervals of approximately 1/2 line period. The line memory unit 15 time-compresses each line period of the digital video signal DV1 into a digital video signal within a time corresponding to approximately 1/2 line period, and is formed 1 /. The digital video signal DX1 for two line periods is sequentially and intermittently obtained.

On the other hand, in the frame memory section 16 to which the digital video signal DV2 from the A / D conversion section 14 is supplied, the digital video signal DV2 is supplied to both the field memory section 17 and the field memory section 18. Then, the write timing signal WF1 from the timing signal forming unit 22 is stored in the field memory unit 17.
And the read timing signal RF1 from the timing signal forming unit 21.

As a result, in the field memory section 17, each odd-numbered field period in the digital video signal DV2 is sequentially written in accordance with the write timing signal WF1 for each of a plurality of line periods included therein, and for reading. In response to the timing signal RF1, each line period included in the written odd field period is time-axis compressed and read with a read time corresponding to approximately 1/2 line period in the video signal SV1. Further, in the field memory unit 18, each even field period in the digital video signal DV2 corresponds to the write timing signal WF2.
Data is sequentially written for each of a plurality of line periods included therein, and according to the read timing signal RF2,
Each line period included in the written even field period is time-axis-compressed and read with a read time corresponding to approximately 1/2 line period in the video signal SV1. That is, in the field memory units 17 and 18, time axis compression reading is performed for each line period included in each of the odd field period and the even field period forming each frame period of the digital video signal DV2. Of.

In this case, when the identification signal CM from the line period number identification unit 23 has a positive polarity, that is, the video signal SV1 is supplied to the video signal input terminal 10 and the video signal input terminal 11 is supplied. When the video signal SV2 is being supplied to the read timing signal R
The time axis compression reading for each line period included in each odd field period in the digital video signal DV2 from the field memory unit 17 performed according to F1 is identified from the start time of the odd field period of the video signal SV1. It starts from a point of time corresponding to the line period in a predetermined number of video signals SV1 corresponding to the difference in the number of line periods represented by the signal CM, and is approximately a half line period in the latter half of each line period in the video signal SV1. And the read timing signal RF2
The time-axis compression reading for each line period included in each even field period in the digital video signal DV2 from the field memory unit 18 is performed in accordance with the identification signal from the start time of the even field period of the video signal SV1. Starting from a time point delayed by a time corresponding to the line period in the predetermined number of video signals SV1 corresponding to the difference in the number of line periods represented by CM, in the approximately half line period of the latter half of each line period in the video signal SV1 Done.

When the identification signal CM from the line period number identification unit 23 has a negative polarity, that is, the video signal SV2 is supplied to the video signal input terminal 10 and the video signal is input to the video signal input terminal 11. When the signal SV1 is being supplied, the read timing signal RF1
The time-axis compression reading for each line period included in each odd field period in the digital video signal DV2 from the field memory unit 17 is performed in response to the identification signal from the start time of the odd field period of the video signal SV1. In the first half approximately 1/2 line period within each line period in the video signal SV1, starting from a point of time corresponding to the line period in the predetermined number of video signals SV1 corresponding to the difference in the number of line periods represented by CM, The time-axis compression reading for each line period included in each even field period in the digital video signal DV2 from the field memory unit 18 is performed at the same time as the read-out timing signal RF2.
The video signal SV1 starts from a time corresponding to a line period in the predetermined number of video signals SV1 corresponding to a difference in the number of line periods represented by the identification signal CM from the start time of the even field period of the video signal SV1. The process is performed in the first half of the line period, that is, approximately ½ line period.

As a result, from the field memory unit 17,
A line period included in each odd field period in the digital video signal DV2 is time-axially compressed into a digital video signal within a time period corresponding to approximately 1/2 line period in the video signal SV1. / 2
Line period The digital video signal DX2O is sequentially obtained intermittently, and the line period included in each even field period in the digital video signal DV2 is approximately 1/2 line period in the video signal SV1 from the field memory unit 18. The half-line period digital video signal DX2E, which is to be formed by time-axis compression into the digital video signal within the time period corresponding to, is sequentially obtained intermittently.

The 1/2 line period digital video signal DX1 obtained from the line memory unit 15 is supplied to the digital video signal selection control unit 24, and the field memory unit 17 and the field memory unit 18 forming the frame memory unit 16 are also provided. The 1/2 line period digital video signal DX2O and the 1/2 line period digital video signal DX2E respectively obtained from the digital video signal selection control unit 2 as the 1/2 line period digital video signal DX2.
4 is supplied. Then, the selection control signal SS from the timing signal forming unit 21 is supplied to the digital video signal selection control unit 24.

When the selection control signal SS from the timing signal forming unit 21 takes a low level, the digital video signal selection control unit 24 has the positive polarity of the identification signal CM from the line period number identification unit 23. Therefore, when the video signal SV1 is supplied to the video signal input terminal 10 and the video signal SV2 is supplied to the video signal input terminal 11, the 1/2 line period digital video signal from the line memory unit 15 is supplied. DX1 is supplied to the selection contact 25A of the signal selection unit 25, and the frame memory unit 1
6-1 / 2 line period digital video signal DX2
To the selection contact 25C of the signal selection unit 25, and
When the selection control signal SS from the timing signal forming unit 21 has a high level, therefore, the identification signal CM from the line period number identification unit 23 has a negative polarity, and the video signal SV2 is supplied to the video signal input terminal 10. When the video signal SV1 is being supplied and is being supplied to the video signal input terminal 11, the 1/2 line period digital video signal DX1 from the line memory unit 15 is applied to the selection contact 25C of the signal selection unit 25. In addition to the supply, the digital video signal DX2 from the frame memory unit 16 for the 1/2 line period
Is supplied to the selection contact 25A of the signal selection unit 25. Then, the selection contact 25A in the signal selection unit 25
The digital image mute signal DM from the image mute signal generation unit 26 is supplied to the selection contact 25B provided between the selection contact 25C and the selection contact 25C.

The signal selecting section 25 is controlled by both the selection control signal SM and the selection control signal SN from the timing signal forming section 21. Then, the line period number identification unit 23
When the identification signal CM from the signal is positive and the video signal SV1 is supplied to the video signal input terminal 10 and the video signal SV2 is supplied to the video signal input terminal 11, the timing signal The selection control signal SM is supplied from the forming unit 21 to the signal selecting unit 25. In the signal selection section 25 to which the selection control signal SM is supplied,
After the start of the period corresponding to each of the odd field period and the even field period of the video signal SV1, first, the video signal for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. The movable contact 25D is the selection contact 2 only for about 1/2 line period in SV1.
5A, and thereafter, the movable contact 25D is connected to the selection contact 25B for about 1/2 line period of the video signal SV1, and subsequently, for about 1/2 line period of the video signal SV1. Moving contact 25D
Is connected to the selection contact 25A, and thereafter, the movable contact 25D is connected to the selection contact 25B for an extremely short time, and further, the movable contact 25D is connected to the selection contact 25C for about 1/2 line period in the video signal SV1. The state in which the movable contact 25D is selected is repeated for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM, and for approximately 1/2 line period in the video signal SV1. While being connected to the contact 25A, the movable contact 25D is connected to the selection contact 25B for a period of about 1/2 line in the video signal SV1.

As a result, in the signal selection section 25,
Corresponding to each odd field period in the video signal SV1, first of all, 1/2 is supplied to the selection contact 25A for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. Line period Digital video signal DX1 is movable only for approximately 1/2 line period 25
After being taken out to D, it is followed by selection contact 2
The state in which the image mute signal DM supplied to 5B is taken out to the movable contact 25D for about 1/2 line period is repeated, and thereafter, the 1/2 line period digital video signal DX1 supplied to the selection contact 25A is about 1 /. The image mute signal D that is taken out to the movable contact 25D for only two line periods and then supplied to the selection contact 25B
After M is taken out to the movable contact 25D for an extremely short time, the 1/2 line period digital video signal DX2O from the field memory unit 17 in the frame memory unit 16 supplied to the selection contact 25C is moved for about 1/2 line period. The state of being taken out to the contact 25D is repeated, and further,
The selection contact 25 is provided for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM.
1/2 line period digital video signal D supplied to A
A state in which X1 is taken out to the movable contact 25D only for about 1/2 line period, and subsequently, the image mute signal DM supplied to the selection contact 25B is taken out to the movable contact 25D for about 1/2 line period is repeated. . As a result, the movable contact 25D in the signal selection unit 25 is
A digital video signal for an odd field period can be obtained.

Corresponding to each even field period in the video signal SV1, first, the selection contact 25A is supplied for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. The 1/2 line period digital video signal DX1 is taken out to the movable contact 25D for about 1/2 line period, and subsequently, the image mute signal DM supplied to the selection contact 25B for about 1/2 line period. The state of being taken out to the movable contact 25D is repeated, and thereafter, the 1/2 line period digital video signal DX1 supplied to the selection contact 25A is taken out to the movable contact 25D for about 1/2 line period, and subsequently, selection is made. After the image mute signal DM supplied to the contact 25B is taken out to the movable contact 25D for an extremely short time, 1 from the field memory unit 18 in the frame memory 16 is supplied to the 択接 point 25C
1/2 line period Digital video signal DX2E is approximately 1/2
The state of being taken out to the movable contact 25D for the line period is repeated, and further, the time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM is supplied to the selection contact 25A 1 /. The digital video signal DX1 for two lines is taken out to the movable contact 25D for about 1/2 line period, and subsequently, the image mute signal DM supplied to the selection contact 25B is about one.
The state of being taken out to the movable contact 25D is repeated only for the / 2 line period. As a result, the movable contact 25D in the signal selection unit 25 can obtain a digital video signal for an even field period.

On the other hand, the identification signal CM from the line period number identification unit 23 has a negative polarity, the video signal SV2 is supplied to the video signal input terminal 10, and the video signal is input to the video signal input terminal 11. When the signal SV1 is being supplied, the timing signal forming unit 21 supplies the selection control signal SN to the signal selecting unit 25. In the signal selection section 25 to which the selection control signal SN is supplied, after the start of the period corresponding to each of the odd field period and the even field period of the video signal SV1, first, the identification signal C
The movable contact 25D is selected by the movable contact 25D for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by M, and for approximately 1/2 line period in the video signal SV1.
While being connected to B, the state in which the movable contact 25D is connected to the selection contact 25C is repeated for about 1/2 line period in the video signal SV1. Then, the movable contact 2 is moved for about 1/2 line period in the video signal SV1.
5D is connected to the selection contact 25A, and thereafter,
The movable contact 25D is connected to the selection contact 25B for an extremely short time, and the movable contact 25D is connected to the selection contact 25C for about 1/2 line period of the video signal SV1. The movable contact 25D is connected to the selection contact 25B for about 1/2 line period of the video signal SV1 for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the video signal. Approximately 1 / in SV1
The movable contact 25D is connected to the selection contact 25C only for two line periods.

As a result, in the signal selection section 25,
Corresponding to each odd field period in the video signal SV1, first, an image mute signal supplied to the selection contact 25B for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. DM is about 1
/ 1 which is taken out to the movable contact 25D for only 2 line periods and then supplied to the selection contact 25C
The state in which the digital video signal DX1 is taken out to the movable contact 25D for a period of about 1/2 line is repeated for a period of 2 lines, and then 1 / from the field memory unit 17 in the frame memory unit 16 is supplied to the selection contact 25A.
The digital video signal DX2O for 2 line periods is taken out to the movable contact 25D for about 1/2 line period, and
Subsequently, after the image mute signal DM supplied to the selection contact 25B is taken out to the movable contact 25D for an extremely short time, the 1/2 line period digital video signal DX1 supplied to the selection contact 25C is substantially 1/2 line. The state of being taken out to the movable contact 25D is repeated for a period, and further,
The selection contact 25 is provided for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM.
The image mute signal DM supplied to B is taken out to the movable contact 25D for about 1/2 line period, and the 1/2 line period digital video signal DX1 supplied to the selection contact 25C is moved for about 1/2 line period. Contact 25D
The state of being taken out is repeated. As a result, the movable contact 25D in the signal selection unit 25 can obtain a digital video signal for an odd field period.

Corresponding to each even field period in the video signal SV1, first, the selection contact 25B is supplied for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. The image mute signal DM to be moved is movable contact 25D only for about 1/2 line period.
And then to the selection contact 25.
1/2 line period digital video signal D supplied to C
The state in which X1 is taken out to the movable contact 25D for approximately 1/2 line period is repeated, and thereafter, the 1/2 line period digital video signal D from the field memory unit 18 in the frame memory unit 16 supplied to the selection contact 25A is repeated.
X2E is taken out to the movable contact 25D only for about 1/2 line period, and subsequently, the image mute signal DM supplied to the selected contact 25B is taken out to the movable contact 25D for an extremely short time and then supplied to the selected contact 25C. 1/2 line period digital video signal DX1 is approximately 1/2
The state of being taken out to the movable contact 25D for the line period is repeated, and further, the image mute supplied to the selection contact 25B for a time corresponding to a predetermined number of line periods corresponding to the difference in the number of line periods represented by the identification signal CM. Signal D
The state in which M is taken out to the movable contact 25D for about 1/2 line period and the 1/2 line period digital video signal DX1 supplied to the selection contact 25C is taken out to the movable contact 25D for about 1/2 line period is repeated. Be done. Thereby, the movable contact 25 in the signal selection unit 25
At D, a digital video signal for an even field period is obtained.

In this way, the line period number identification unit 23
When the identification signal CM from is positive and the video signal SV1 is supplied to the video signal input terminal 10 and the video signal SV2 is supplied to the video signal input terminal 11, and The identification signal CM from the line period number identification unit 23 has a negative polarity, and the video signal SV2 is supplied to the video signal input terminal 10 and the video signal SV1 is supplied to the video signal input terminal 11. , The digital video signal for the odd field period and the digital video signal for the even field period, which are derived to the movable contact 25D of the signal selection unit 25, are converted into digital / analog conversion units (D / A conversion units). )
It is supplied to 27, is subjected to analogization, and is used as a video signal SZ for two-screen image display.

The dual-screen image display video signal SZ obtained from the D / A converter 27 is a low pass filter (LPF) 2
After the noise component is removed through 8, the image is supplied to the dual-screen image display unit 29. The two-screen image display unit 29 has an image display surface on which line scanning and field scanning are performed, and on the image display surface, a screen of an image represented by the video signal SV1 and a screen of an image represented by the video signal SV2. And are formed to be arranged adjacent to each other in the left-right direction across the image mute portion based on the digital image mute signal DM, which forms a boundary line extending in the vertical direction. That is, the dual-screen image display unit 29 performs dual-screen image display based on the dual-screen image display video signal SZ, and the identification signal CM from the line period number identification unit 23 has a positive polarity. Video signal SV to video signal input terminal 10
When 1 is supplied and the video signal SV2 is supplied to the video signal input terminal 11, the left side of the two screens divided by the vertical line image mute section based on the digital image mute signal DM The image represented by the video signal SV1 is displayed on the right side of the two screens, and the image represented by the video signal SV2 is displayed on the right side of the two screens, and the identification signal CM from the line period number identification unit 23 is When the video signal SV2 has a negative polarity and the video signal SV2 is supplied to the video signal input terminal 10 and the video signal SV1 is supplied to the video signal input terminal 11, the vertical direction based on the digital image mute signal DM is generated. An image represented by the video signal SV2 is displayed on the left side of the two screens divided by the linear image mute section, and the two screens are displayed. State right in the image indicated by the image signal SV1 of out is displayed is taken.

At this time, the identification signal CM from the line period number identification section 23 has a positive polarity, and the video signal input terminal 1
When the video signal SV1 is supplied to 0 and the video signal SV2 is supplied to the video signal input terminal 11, the two-screen image display unit 29 is arranged on the left and right as shown in FIG. An image I1 represented by the video signal SV1 is displayed over the entire screen on the left side of the two-screen image, and an image I2 represented by the video signal SV2 is displayed on the right side of the left and right two-screen images.
The image is displayed with the image mute section ZM based on the digital image mute signal DM extending upward and downward in the left-right direction. Further, the identification signal C from the line period number identification unit 23
When M has a negative polarity and the video signal SV2 is supplied to the video signal input terminal 10 and the video signal SV1 is supplied to the video signal input terminal 11, the two-screen image display unit 29 is displayed. In FIG. 5, the image I2 represented by the video signal SV2 is provided on the left side of the left and right two-screen image with the image mute section ZM based on the digital image mute signal DM extending in the left and right directions upward and downward. The video signal SV1 is displayed on the right side of the dual-screen image that is displayed along with it.
The image I1 shown is displayed over the entire screen.

Therefore, in the two-screen image displayed on the two-screen image display unit 29 in this way, each of the two images is not partially deleted, and the user of the apparatus is dissatisfied. Or it will not give a strange feeling. The dual-screen image displayed on the dual-screen image display unit 29 is always arranged on the left side of the image represented by the video signal SV1 or SV2 supplied to the video signal input terminal 10, and at the video signal input terminal 11. The image represented by the supplied video signal SV2 or SV1 is arranged on the right side, and the situation in which the user of the apparatus is confused can be avoided.

Under the circumstances, the video signal selection control unit 12,
The portion including the timing signal forming unit 21, the line period number identifying unit 23, and the like has a large number of line periods included in each frame period of the video signals SV1 and SV2 supplied to the video signal input terminals 10 and 11. The video signals SV1 and SV so that the video signal SV1 of one side is always the first video signal supplied to the A / D converter 13 is used.
A signal transmission control unit that controls the transmission state of the signal No. 2 is configured.

[0058]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the example shown in FIG. 1, the video signal SV1 is a PAL video signal and the video signal SV is
2 is an NTSC video signal, the number of line periods included in each frame period is 62 in the PAL video signal.
In the NTSC video signal, the number of line periods included in each frame period is 525. Therefore, the number of line periods included in each frame period of the video signal SV1 and each frame period of the video signal SV2 are included. The difference from the number of line periods to be set is "100".

Then, the PAL video signal as the video signal SV1 is supplied to the video signal input terminal 10,
NTSC video signal as V2 is video signal input terminal 11
Is supplied to the line period number identifying unit 23,
An identification signal CM having a positive polarity and representing the difference in the number of line periods “100” is obtained, and the identification signal CM is supplied to the timing signal forming unit 21. Thereby,
The read timing signal RL supplied from the timing signal forming unit 21 to the line memory unit 15 is the time-axis compressed read-out of the signal written in it from the line memory unit 15, and the first half of each line period in the PAL video signal. The read timing signal RF1 supplied to the field memory unit 17 is obtained in about 1/2 line period, and the time-axis compression read of the signal written in it from the field memory unit 17 is performed. Is delayed from the start time of the odd field period of the PAL video signal by a time corresponding to 100/2 = 50 line periods in the PAL video signal set corresponding to the difference 100 in the number of line periods represented by the identification signal CM. Starting from the point of time, approximately 1 in the latter half of each line period in the PAL video signal With resulting are those for performing the two-line period, the field memory unit 18
The read timing signal RF2 supplied to the field memory unit 18 indicates the time-axis compressed read of the signal written therein from the field memory unit 18 from the start point of the even field period of the PAL video signal to the number of line periods represented by the identification signal CM. To start from a point delayed by a time corresponding to the 50 line period in the PAL video signal set corresponding to the difference “100”, and to perform in approximately the latter half line period of each line period in the PAL video signal. It is supposed to be obtained. Further, the timing signal forming unit 21
From which a selection control signal SS having a low level is obtained,
It is supplied to the video signal selection control unit 12 and the digital video signal selection control unit 24, and the selection control signal SM is obtained and supplied to the signal selection unit 25.

Then, in the video signal selection control section 12, the PAL video signal as the video signal SV1 from the video signal input terminal 10 is supplied to the A / D conversion section 13 in response to the selection control signal SS having a low level. And NTSC as the video signal SV2 from the video signal input terminal 11
The video signal is supplied to the A / D converter 14. At this time, in the line memory unit 15, time-axis compression reading for each line period in the digital video signal DV1 is performed in approximately the first half line period in each line period in the PAL video signal, whereby 1 The digital video signal DX1 is formed in the / 2 line period and is supplied to the digital video signal selection controller 24.

Further, in the frame memory section 16 including the field memory sections 17 and 18, each odd field period included in the digital video signal DV2 from the field memory section 17 is included in each frame in accordance with the read timing signal RF1. When the time-axis compression reading for the line period is performed, the difference in the number of line periods represented by the identification signal CM from the start point of the odd field period of the PAL video signal is “1”.
5 in the PAL video signal set corresponding to "00"
The operation is started from a time point delayed by a time corresponding to the 0 line period, and is performed in the approximately 1/2 line period of the latter half of each line period in the PAL video signal, and the 1/2 line period digital video signal DX2O is formed. According to the read timing signal RF2, the time axis compression reading for each line period included in each even field period in the digital video signal DV2 from the field memory unit 18 starts the even field period of the PAL video signal. It starts from a point of time corresponding to the 50 line period in the PAL video signal set corresponding to the difference "100" in the number of line periods represented by the identification signal CM from the time point, and the latter half of each line period in the PAL video signal. Is performed in approximately 1/2 line period, and digital video is performed in the 1/2 line period. No. DX2E is formed.

Then, 1 / each obtained from the field memory units 17 and 18 included in the frame memory unit 16
The 2-line period digital video signal DX2O and the 1/2 line period digital video signal DX2E are supplied to the digital video signal selection control section 24 as the 1/2 line period digital video signal DX2. In the digital video signal selection control unit 24, the 1/2 line period digital video signal DX1 from the line memory unit 15 is supplied to the selection contact 25A in the signal selection unit 25 in accordance with the selection control signal SS having a low level. , 1/2 line period digital video signal DX from the frame memory unit 16
2 is supplied to the selection contact 25C in the signal selection unit 25.

In the signal selection section 25, the difference in the number of line periods represented by the identification signal CM is "100" corresponding to each odd field period and each even field period in the PAL video signal in accordance with the selection control signal SM. ”
The 1/2 line period digital video signal DX1 supplied to the selection contact 25A is approximately 1/1 for the time corresponding to the 50 line period in the PAL video signal set corresponding to
The image mute signal DM, which is taken out to the movable contact 25D for two line periods and is subsequently supplied to the selection contact 25B, is moved to the movable contact 25 for about 1/2 line period.
The state of being taken out to D is repeated, and thereafter, the 1/2 line period digital video signal DX1 supplied to the selecting contact 25A is taken out to the movable contact 25D for about 1/2 line period, and subsequently, the selecting contact 25B. After the image mute signal DM supplied to the movable contact 25D is taken out for an extremely short time, a 1/2 line period from the frame memory unit 16 supplied to the selection contact 25C is applied to the digital video signal DX2 for about 1/2 line period. The state of being taken out to the movable contact 25D is repeated, and further, the selection contact 25A is applied to the selection contact 25A for a time corresponding to 50 line periods in the PAL video signal set corresponding to the line period number difference "100" represented by the identification signal CM. 1/2 supplied
In the line period, the digital video signal DX1 is taken out to the movable contact 25D only for about 1/2 line period, and subsequently, the image mute signal DM supplied to the selection contact 25B is taken out to the movable contact 25D for about 1/2 line period. The state of being repeated is repeated. As a result, the movable contact 25D in the signal selection unit 25 alternately obtains the digital video signal for the odd field period and the digital video signal for the even field period.

The digital video signal for the odd field period and the digital video signal for the even field period, which are led to the movable contact 25D of the signal selecting section 25, are D / A.
The conversion unit 27 performs analogization to obtain a two-screen image display video signal SZ.

The video signal SZ for displaying a two-screen image is
The PAL video signal as the video signal SV1 is formed as a reference.

The two-screen image display video signal SZ obtained from the D / A conversion unit 27 is supplied to the two-screen image display unit 29 through the LPF 28, whereby the two-screen image display unit 29 displays the two-screen image for display. As shown in FIG. 6, in the two-screen image display based on the video signal SZ, the image P represented by the PAL video signal is displayed on the left side of the two screens divided by the vertical line image mute section XM, and The image N represented by the NTSC video signal is displayed on the right side of the two screens. The image N on the right side represented by the NTSC video signal is accompanied by an image mute section ZM above and below it based on the digital image mute signal DM. At this time, the image P represented by the PAL video signal is formed by, for example, 580 horizontal scanning lines, and the image N represented by the NTSC video signal is formed by, for example, 490 horizontal scanning lines. It is assumed that both the image P represented by the PAL video signal and the image N represented by the NTSC video signal are substantially displayed without any deleted portion.

On the other hand, N as the video signal SV2
In the case where the TSC video signal is supplied to the video signal input terminal 10 and the PAL video signal as the video signal SV1 is supplied to the video signal input terminal 11, the line period number identification unit 23 has a negative polarity. , Line period difference "100"
Is obtained, and the identification signal CM is supplied to the timing signal forming section 21.
As a result, the read timing signal RL supplied from the timing signal forming unit 21 to the line memory unit 15 is obtained.
Is obtained for performing the time-axis compression reading of the signal written therein from the line memory unit 15 in the latter half of each line period of the PAL video signal, that is, approximately 1/2 line period. The read timing signal RF1 supplied to the section 17 indicates the time-axis compressed read of the signal written therein from the field memory section 17 from the start point of the odd field period of the PAL video signal by the identification signal CM. PAL set corresponding to the difference in the number of periods "100"
It is assumed that the operation is started from a time point delayed by a time corresponding to 100/2 = 50 line periods in the video signal, and is performed in approximately the first half line period of each line period in the PAL video signal. , The read timing signal R supplied to the field memory unit 18.
F2 performs the time-axis compression reading of the signal written in it from the field memory unit 18 from the start point of the even field period of the PAL video signal, and the identification signal CM.
Starting from a point delayed by a time corresponding to 50 line periods in the PAL video signal set corresponding to the difference in the number of line periods represented by "100", approximately 1/2 of the first half of each line period in the PAL video signal is started. Obtained as being for doing during the line period. Further, from the timing signal forming unit 21, the selection control signal S having a high level is output.
S is obtained and is supplied to the video signal selection control unit 12 and the digital video signal selection control unit 24, and the selection control signal SN is obtained and supplied to the signal selection unit 25.

Then, in the video signal selection control unit 12, the PAL video signal as the video signal SV1 from the video signal input terminal 11 is supplied to the A / D conversion unit 13 in response to the selection control signal SS having a high level. And NTSC as the video signal SV2 from the video signal input terminal 10.
The video signal is supplied to the A / D converter 14. At this time, in the line memory unit 15, the time-axis compression reading for each line period of the digital video signal DV1 is performed in the latter half line period of each line period of the PAL video signal, whereby 1 The digital video signal DX1 is formed in the / 2 line period and is supplied to the digital video signal selection controller 24.

Further, in the frame memory unit 16 including the field memory units 17 and 18, each odd field period included in the digital video signal DV2 from the field memory unit 17 is included in each of the odd field periods in accordance with the read timing signal RF1. When the time-axis compression reading for the line period is performed, the difference in the number of line periods represented by the identification signal CM from the start point of the odd field period of the PAL video signal is “1”.
5 in the PAL video signal set corresponding to "00"
It is started from a time point delayed by a time corresponding to the 0 line period, and is performed in approximately the first half line period of each line period in the PAL video signal, and the 1/2 line period digital video signal DX2O is formed. According to the read timing signal RF2, the time axis compression reading for each line period included in each even field period in the digital video signal DV2 from the field memory unit 18 starts the even field period of the PAL video signal. The first half of each line period in the PAL video signal is started from a time point delayed by a time corresponding to 50 line periods in the PAL video signal set corresponding to the difference 100 between line periods represented by the identification signal CM from the time point. Is performed in approximately 1/2 line period, and digital video is performed in the 1/2 line period. No. DX2E is formed.

Then, 1 / each obtained from the field memory units 17 and 18 included in the frame memory unit 16
The 2-line period digital video signal DX2O and the 1/2 line period digital video signal DX2E are supplied to the digital video signal selection control section 24 as the 1/2 line period digital video signal DX2. In the digital video signal selection control unit 24, the 1/2 line period digital video signal DX1 from the line memory unit 15 is supplied to the selection contact 25C in the signal selection unit 25 in accordance with the selection control signal SS having a high level. , 1/2 line period digital video signal DX from the frame memory unit 16
2 is supplied to the selection contact 25A in the signal selection unit 25.

In the signal selection section 25, the difference in the number of line periods represented by the identification signal CM is set to "100" corresponding to each odd field period and each even field period in the PAL video signal in accordance with the selection control signal SN. ”
The image mute signal DM supplied to the selection contact 25B is taken out to the movable contact 25D for about 1/2 line period for a time corresponding to 50 line periods in the PAL video signal set corresponding to hand,
The 1/2 line period digital video signal DX2 supplied from the frame memory section 16 to the selection contact 25A is approximately 1 /
The state of being taken out to the movable contact 25D for two line periods is repeated, and thereafter, the 1/2 line period digital video signal DX2 supplied from the frame memory unit 16 to the selection contact 25A is moved to the movable contact 25D for about 1/2 line period.
And then to the selection contact 25.
After the image mute signal DM supplied to C is taken out to the movable contact 25D for an extremely short time, the 1/2 line period digital video signal DX1 supplied to the selection contact 25C is transmitted to the movable contact 25D for about 1/2 line period. The state of being taken out is repeated, and further, the image supplied to the selection contact 25B for a time corresponding to 50 line periods in the PAL video signal set corresponding to the difference 100 between the line periods represented by the identification signal CM. Mute signal DM is about 1
The frame memory unit 1 that is taken out to the movable contact 25D for only 1/2 line period and is supplied to the selection contact 25A
The state in which the 1/2 line period digital video signal DX2 from 6 is taken out to the movable contact 25D for approximately a 1/2 line period is repeated. As a result, the movable contact 25D in the signal selection unit 25 alternately obtains the digital video signal for the odd field period and the digital video signal for the even field period.

The digital video signal for the odd field period and the digital video signal for the even field period, which are led to the movable contact 25D of the signal selecting section 25, are D / A.
The conversion unit 27 performs analogization to obtain a two-screen image display video signal SZ.

The two-screen image display video signal SZ is also
The PAL video signal as the video signal SV1 is formed as a reference.

The two-screen image display video signal SZ obtained from the D / A conversion unit 27 is supplied to the two-screen image display unit 29 through the LPF 28, whereby the two-screen image display unit 29 displays the two-screen image for display. As shown in FIG. 7, in the two-screen image display based on the video signal SZ, the image N represented by the NTSC video signal is displayed on the left side of the two screens partitioned by the vertical line image mute section XM, and The image P represented by the PAL video signal is displayed on the right side of the two screens. The image N on the left side represented by the NTSC video signal is accompanied by an image mute section ZM above and below it based on the digital image mute signal DM. Also in this case, the image N represented by the NTSC video signal is formed by, for example, 490 horizontal scanning lines, and the image P represented by the PAL video signal is, for example, 580 horizontal scanning lines. The image N represented by the NTSC video signal and the image P represented by the PAL video signal are substantially displayed without any deleted portion.

[0075]

As is apparent from the above description, in the image display device according to the present invention, a plurality of line periods included in each frame period of the first video signal are stored in the line memory section. The first time-axis compressed signal is obtained by performing time-axis compression using the plurality of line periods included in each frame period of the second video signal, and the first video signal is generated using the frame memory unit. By time-compressing at a timing synchronized with the synchronization signal of the signal, obtaining a second time-axis compression signal synchronized with the first time-axis compression signal, and combining the first and second time-axis compression signals When obtaining two-screen image display video signals, two video signals are always provided when the two video signals, which are the first and second video signals, differ in the number of line periods included in each frame period. Each of Those who number line period contained in frame period is large so as to the first video signal, the transmission control for the two video signals is carried out. As a result, the obtained two-screen image display video signal is based on the one having the larger number of line periods included in each frame period of the two video signals as the first and second video signals. Will be formed.

Therefore, in the two-screen image displayed by the two-screen image display section in accordance with such a two-screen image display video signal, it is assumed that the number of line periods included in each frame period is larger. The image represented by the first video signal is generally displayed as the one having a large number of horizontal scanning lines forming it, and the one having a small number of line periods included in each frame period. The image represented by the second video signal is wholly displayed together with the image mute section as the one having the smaller number of horizontal scanning lines forming the image.

Therefore, according to the image display device of the present invention, the number of line periods included in each frame period of the two video signals of the first video signal and the second video signal is different. At this time, the video signal for dual-screen image display obtained based on these two video signals should not be partially deleted from the dual-screen image displayed by the image display section based on it. Will be done,
It is avoided that the user of the device becomes dissatisfied or has a strange feeling.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an example of an image display device according to the present invention.

FIG. 2 is a time chart used for explaining the operation of the example shown in FIG.

FIG. 3 is a time chart used for explaining the operation of the example shown in FIG.

FIG. 4 is a conceptual diagram showing a dual-screen image display state provided for explaining the operation of the example shown in FIG.

FIG. 5 is a conceptual diagram showing a dual-screen image display state provided for explaining the operation of the example shown in FIG.

FIG. 6 is a conceptual diagram showing a dual-screen image display state provided for explaining the operation of a specific example of the example shown in FIG. 1.

FIG. 7 is a conceptual diagram showing a two-screen image display state used for explaining the operation of a specific example of the example shown in FIG. 1.

FIG. 8 is a time chart used for explaining time-axis compression of a video signal using a line memory.

FIG. 9 is a conceptual diagram for explaining a dual-screen image display.

FIG. 10 is a conceptual diagram for explaining a dual-screen image display.

[Explanation of symbols]

 10, 11 Video signal input terminal 12 Video signal selection control unit 13, 14 A / D conversion unit 15 Line memory unit 16 Frame memory unit 17, 18 Field memory unit 19, 20 Sync signal separation unit 21, 22 Timing signal forming unit 23 Line period number identification unit 24 Digital video signal selection control unit 25 Signal selection unit 26 Image mute signal generation unit 27 D / A conversion unit 28 LPF 29 Dual screen image display unit

Claims (9)

[Claims] 1. A first and second video signal input terminal to which two video signals, which are a first video signal and a second video signal, are supplied, and the first video signal is sequentially provided for one line period. While being written, each line period of the written first video signal is read and formed within a time period corresponding to approximately 1/2 line period of the first video signal.
/ 2 line period video signals are obtained intermittently in sequence, and an odd field period and an even field period forming each frame period of the second video signal are sequentially written and written. The line period included in the odd field period is read out intermittently within the time corresponding to approximately 1/2 line period of the first video signal, and the second 1/2 line period is read. And the line period included in the written even field period is intermittently within a time corresponding to approximately 1/2 line period of the first video signal. It corresponds to each frame period of the first video signal, and a frame memory unit which is alternately read out and in which a video signal for the third 1/2 line period is sequentially obtained intermittently. The video signal for the first 1/2 line period obtained from the line memory unit and the video signal for the second 1/2 line period obtained from the frame memory unit or the third 1/2 for every interval. An image based on the first video signal according to the signal selection unit that selectively extracts the video signal for the line period and forms the display video signal, and the display video signal obtained from the signal selection unit And a two-screen image display section that displays a two-screen image corresponding to the image based on the second video signal, and two video signals supplied to the first and second video signal input ends, respectively. When the number of line periods included in the frame period is different, the one having the larger number of line periods included in each frame period of the two video signals is always referred to as the first video signal. To do this, the above two images The image display apparatus constructed and a signal transmission control unit for controlling the transmission status of the signal. 2. The signal transmission control unit, the number of line periods included in each frame period of the video signal supplied to the first video signal input end, and the video signal supplied to the second video signal input end. The line period number identifying section for identifying the number of line periods included in each frame period and for issuing an identification output signal representing an identification result, and in accordance with the identification output signal obtained from the line period number identifying section, A state in which the video signal supplied to the first video signal input terminal is used as the first video signal;
2. The image display device according to claim 1, wherein the image signal supplied to the second image signal input terminal is selectively set to the first image signal. 3. A signal transmission control unit which has a large number of line periods included in each frame period of the two video signals supplied to the first and second video signal input ends. The selection control for the two video signals is performed in order to supply to the line memory unit the one having the smaller number of line periods included in each frame period of the two video signals to the frame memory unit. The image display apparatus according to claim 1, further comprising a video signal selection control unit for performing the operation. 4. The number of line periods included in each frame period of the video signal supplied to the first video signal input end and the video signal supplied to the second video signal input end by the signal transmission control unit. A line period number identifying unit that identifies the number of line periods included in each frame period and issues an identification output signal that represents the identification result, and the video signal selection control unit determines the identification output obtained from the line period number identifying unit. 4. The image display device according to claim 3, wherein selection control is performed for the two video signals supplied to the first and second video signal input ends according to a signal. 5. The number of line periods included in each frame period of the video signal supplied to the first video signal input end and the video supplied to the second video signal input end by the line period number identification unit. 5. The image display device according to claim 2, wherein a difference from the number of line periods included in each frame period of the signal is detected, and an identification output signal according to the detected difference is transmitted. 6. A write-read timing control means for adjusting write-read timing for an odd field period and an even field period for forming each frame period of a second video signal in a frame memory section. When the two video signals supplied to the first and second video signal input terminals are different in the number of line periods included in each frame period, the write-read timing control means controls the frame. Second from the memory section
Of 1/2 line period is intermittently obtained and the third 1/2 line period is intermittently obtained in synchronization with each field period of the first video signal. And a state in which the second 1/2 line period portion is sequentially and intermittently obtained from the frame memory unit and a third 1/2 line period portion is sequentially and intermittently obtained from the frame memory unit. 2. The image according to claim 1, wherein the start time of is delayed from the start times of the odd and even field periods of the first video signal by a time corresponding to a predetermined number of line periods in the first video signal. Display device. 7. The write-read timing control means includes a time corresponding to a line period in a predetermined number of first video signals in each frame period of the video signal supplied to the first video signal input end. 7. The image display according to claim 6, wherein the number of line periods is set according to the difference between the number of line periods included in each frame period of the video signal supplied to the second video signal input end. apparatus. 8. The signal selection unit selects a display video signal, and an image based on the video signal supplied to the first video signal input end is one of two screen images displayed by the two-screen image display unit. The image display device according to claim 1, wherein the image display device is formed so as to be obtained as one of the arrangement positions specified. 9. A video signal and frame memory for a first 1/2 line period obtained from a line memory unit, wherein a signal selection unit uses a period corresponding to each field period of the first video signal as a unit division period. Second or third obtained from the department
When the video signal for the 1/2 line period and the image mute signal are selectively taken out and the video signal supplied to the first video signal input end is the first video signal, In the unit division period, first, a time corresponding to the line period in the predetermined number of the first video signals,
For each period corresponding to each line period of the first video signal, the video signal for the first 1/2 line period and the image mute signal are sequentially taken out, and then the first video signal is set. For each period corresponding to each line period of the video signal,
The video signal for the first 1/2 line period and the video signal for the second or third 1/2 line period are sequentially taken out, and then a predetermined number of the first video signals are taken. In the first period, the period corresponding to each line period of the first video signal,
/ 2 line period of the video signal and the image mute signal are sequentially taken out, and when the video signal supplied to the second video signal input end is the first video signal, the unit division period In the first, the image mute signal and the first 1/2 The video signal for the line period is sequentially taken out, and then the video signal for the second or third 1/2 line period is provided for each period corresponding to each line period of the first video signal. And a video signal for the first 1/2 line period are sequentially taken out, and then, for a time corresponding to a line period in the predetermined number of the first video signals, for each of the first video signals. Corresponding to the line period Between every image display apparatus according to claim 8, wherein the take sequentially retrieving condition and the image muting signal and the first half line period video signal.