JPH0198384A - Superimpose automatic level-down device - Google Patents

Abstract

PURPOSE:To attain ease of reading of a character on a display device by decreasing automatically the level of the superimposing video image in superimposing a moving picture from other video image source. CONSTITUTION:Each primary color signal from an input terminal 1 is given to memories 5r, 5g, 5b, 6r, 6g, 6b respectively via buffer circuits 2r, 2g, 2b, LPFs 3r, 3g, 3b and A/D conversion circuits 4r, 4g, 4b. The superimposing video signal is given to a superimpose circuit 12 via an input terminal 28 or 29 and a switch 30 and a half-down circuit 27. The half-down circuit 27 decreases automatically the video image level to be superimposed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a superimpose automatic level down device that is applied to a device that plays back a recording medium on which music signals and video signals such as text and graphics are recorded. Regarding.

(Prior Art) There is a so-called compact disc in which music information is converted into a digital signal and is formed by bits on the disc, but this disc records not only music signals but also video signals such as text or still images along with music VJs. There are things that have been done.

For example, information such as the title of the music to be played, still images to enhance the atmosphere, or lyrics to be sung to the accompaniment of the music may be recorded along with the music signal on a disc that is played by a so-called karaoke device. Conventionally, there has been a system in which a person can sing the title, still image, or lyrics while looking at the display.

When playing a disc on which video signals such as text, still images, etc. are recorded along with music signals as described above, with an empty device,
A video source other than the above disc, such as VT, is displayed on the plain background of the title or lyrics played on the display.
There are cases where it is desired to insert (superimpose) video from a video tape recorder, video disk, broadcast, etc.

This is used when you want to watch a live sports video while looking at the title or lyrics of a Karaoke, or when you want to watch your favorite video as a background.

To deal with this kind of request, J3 sets the plain background color of the video title or lyrics to one specific color, detects this one specific color, and uses another video source instead of this specific color. There are devices that superimpose videos.

Further, because of the recording problems of the medium, the images recorded on compact discs are generally still images, and the images are generally video screens with solid colored borders around them. Further, it is common that still images and text information such as titles or lyrics are not recorded on a disc at the same time.

(Problem to be solved by the invention) In this way, in order to superimpose a video from another video source instead of a specific color, the background color of the title and lyrics must be set to one specific color. However, if the discs are made by different manufacturers and the background colors of the characters in the video are different, superimposition cannot be performed.

Furthermore, if the superimposed image is at the same level as the text, there is a problem that the text is difficult to read on the display.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a magnitude comparator that compares each RGB primary color signal of a first video signal with predetermined upper and lower limit values; A logic circuit that outputs a discrimination signal when the comparator discriminates a predetermined color, a synchronization separation circuit that separates the synchronization signal of the second video signal, and a mono multivibrator whose output signal is inverted by the output signal of the surface logic circuit. an AND circuit that takes the logical product of the output signals of the mono multivibrator and the synchronization separation circuit; and a voltage dividing circuit that divides the level of the second video signal under the control of the output signal of the AND circuit. a superimpose circuit that is supplied with the output signal of the voltage dividing circuit and the first video signal and is controlled by the output signal of the logic circuit, and the magnitude comparator sets the first video signal to the predetermined value. When determining the color, the superimpose circuit inserts the second video signal voltage-divided by the voltage divider circuit except for the period of the synchronization signal, instead of the predetermined color. To provide an automatic level down device for superimposition.

(Embodiment) FIG. 1 is a block diagram of an embodiment of the superimpose automatic level down device of the present invention.

In Figure 1, 1 is an input terminal (21-bin connector) to which video signals such as RGB primary color signals and composite synchronization signals, which are obtained by converting the 4-bit digital signal reproduced from the compact disc into analog signals, are supplied. ).

One dog's primary color signal (hereinafter referred to as R
signal) includes a buffer circuit 2r, a low-pass filter (LPF) 3r, and an analog-to-digital conversion circuit (△/
The data is supplied to memories 5r and 6r, which store information in field units, through D conversion circuits>4r in series, respectively.

The output signals of the memories 5r, 5r are supplied to a digital-to-analog conversion circuit (D/A conversion circuit) 8r and a comparator 9r, respectively, via a data selector 7r that selects the output signals.

The output signal of this D/A conversion circuit 8r is transmitted to the buffer circuit 1.
The output signal of the comparator 9r is sent to the superimpose circuit 12 via the latch circuit 11r and
They are respectively supplied to the circuits 13.

The G primary color signal and B primary color signal (hereinafter referred to as G signal and B signal) supplied to the input terminal 1 are sent to the superimpose circuit 12 and the AND circuit 13 through the same blocks as those for the R signal. are supplied to each
The G signal is shown as a block with a suffix q added to a number, and the B signal is shown as a block with a suffix s added to a number.

The output signal of the superimpose circuit 12 is supplied to output terminals 16 and 17 via a buffer circuit 14 and a switch 15, respectively. Reference numeral 18 denotes a muting circuit that can control the switch 15 to cut off signals to the output terminals 16 and 17 when the power is turned on.

The composite synchronization signal supplied to the input terminal 1 is supplied to a timing control circuit 20, a switch circuit 21, and a counter 22, respectively, via a synchronization separation circuit 19 that separates horizontal and vertical synchronization signals.

The output signal of the counter 22 is supplied through a delay circuit 23 and a latch circuit 24 in series to a gate circuit 25 whose output signal is supplied to the superimpose circuit 12.
The output signal of the ND circuit 13 is also supplied. switch 2
6 short-circuits the signal terminals a and b of the gate circuit 25 or grounds the terminal a.

The output signal (burst flag pulse) from the timing control circuit 20 is supplied to the half-down circuit 27 and the superimpose circuit 12.

On the other hand, the video signal to be superimposed is input to the input terminal 28.
or 29, the output signal of the buffer circuit 31 is supplied to the synchronous separation circuit 32 and the half-down circuit 27, and the output signal of the half-down circuit 27 is superimposed. It is supplied to the circuit 12.

The horizontal and vertical synchronizing signals sent from the 1111 separation circuit 32 are sent to the switch circuit 21, and the vertical synchronizing signals are sent to the video signal detection circuit 33, which detects the absence of the video signal.
These signals are supplied to the switch circuits 21, respectively.

The upper 4 bits of the 6-bit output signals of the analog-to-digital conversion circuits 4r, 4G, and 4b are each connected to an AND circuit 34.
The signal is supplied to the latch circuit 24 via.

35 is a microcomputer that controls the timing control circuit 20.

FIG. 2 is a detailed circuit diagram of the superimpose circuit 12 and the half-down circuit 27.

The operation of the superimpose automatic level down device of the present invention having such a configuration will be explained.

RGB corresponding to the image of text on a plain background to input terminal 1
Assume that primary color signals of . Among the RGB primary color signals, the impedance of the R signal is matched by a buffer circuit 2r, high frequency components are removed by a low-pass filter 3r, and the R signal is converted into a 6-bit digital signal by an analog-to-digital conversion circuit 4r.

The converted digital signals are alternately stored in the memories 5r and 5r in field units. This memory 5r, 6
Reading and writing of signals to r is controlled by a timing control circuit 20.

Furthermore, desired data is extracted from the IC signals stored in the memories 5r, 5r by a data selector 7r controlled by a timing control circuit 20.

The switch circuit 21 is a circuit that selects, from the video signal supplied to the input terminal 28 or 29, the horizontal and vertical synchronization signals separated by the synchronization separation circuit 32 and the synchronization signal produced by the synchronization separation circuit 19. Priority is given to the signal from the separation circuit 32. In this operation, the switch circuit 21 is turned on by the video signal \J detection circuit 33.

By supplying the horizontal and vertical synchronization signals from the synchronization separation circuit 19 to the timing control circuit 20,
Memories 5r, 5g, 5b described above.

The writing of the signals 5r and 60.6b is synchronized, and the horizontal and vertical synchronizing signals from the switch circuit 21 are also synchronized with the reading.

The data taken out from the data selector 7r is converted into an analog value by a digital-to-analog conversion circuit 8r, and then impedance matched with the superimpose circuit 12 by a buffer circuit 10r. G signal and B
The same effect as in the case of the R signal is also performed on each signal.

On the other hand, the comparators 9r, 9Q, and 9b are used to compare with preset values.
The preset values 9g and 9b are for detecting specific colors, and are set corresponding to the colors to be handled by the superimpose circuit 12.

These comparators 9r, 9g, and 9b all use a magnitude comparator that compares the upper and lower limits of data, so even if there are subtle level fluctuations in the analog signal obtained at input terminal 1, accurate color can be obtained. Can be identified.

If all of the comparators 9r and 90.9b match the preset values, it means that the specific color has been obtained at the input terminal 1, and the output signal of the AND circuit 13 passes through the gate circuit 25. Then, the superimpose circuit 12 is operated.

That is, among the video signals supplied to the input terminal 28 or 29, the signal selected by the switch 30 is inserted into the part from which the specific color around the character is extracted, and the signal is output from the output terminal 16 or 17 by the switch 15 to the outside. It is taken out.

FIG. 3 is a diagram for explaining the balk of a still image on a so-called compact disc used in the present invention.A still image on a compact disc has a balk around the screen, and this balk is black or a plain color. In the case of the NTSC television standard system, there are 262 horizontal scanning lines in the vertical direction.
There are still images in 192 of the 5th tree and middle, and 3 of each of the top
Five of them are black or plain colored. Further, in the horizontal direction, there are still images for 288 dots for 512 dots 1- of one horizontal scanning line, and 112 dots on the left and right sides are black or plain color.

By detecting this balk, it is possible to identify whether the image is a still image or a character image.

Here, it is assumed that the input terminal 1 is supplied with a video signal corresponding to a video screen with a plain color picture frame around it.

The AND circuit 34 includes analog-to-digital conversion circuits 4r, 4
The logical product of the upper 4 bits of the 6-bit output signal of q and 4b is calculated. Here, the logic 111 is set to the black level, and the AND circuit 34 can detect the black level.

The counter 22 starts counting horizontal synchronization signals in response to the vertical synchronization signal from the synchronization separation circuit 19, and
When the 17th grain of the horizontal scanning line of one field, which is approximately in the middle of 35 horizontal scanning FA lines, is counted as a1, a detection signal is sent out. This detection signal is delayed by approximately 1/2 of one horizontal scanning time (here, 30 μSEC) by the delay circuit 23. Due to these actions, 17
This means that the center of the horizontal scanning line of the wood grain has been identified.

Alternatively, the lower side of the balk, that is, the middle of the 244th horizontal scanning line may be specified.

In the above case, if the AND circuit 34 detects the black level, the latch circuit 24 latches it, and if the switch 26 is on the b side, the gate circuit 25 detects the video signal supplied to the input terminal 1. The signal passes through the superimpose circuit 12 as it is and is sent out from the output terminal 16 or 17. On the other hand, if the switch 26 is on the ground side, the gate circuit 25 outputs the external video signal supplied to the input terminal 28 or 29, not the video signal supplied to the input terminal 1, to the superimpose circuit 12 as it is. It is controlled so that it passes through and is sent out from output terminal 16 or 17.

Next, a half-down circuit 2 that is a circuit that automatically lowers the level of the video signal from the superimpose circuit 12 and the buffer circuit 31 inserted into the background of the characters by, for example, 6 db.
7 will be explained in detail.

In FIG. 2, the same components as those in FIG. 1 are given the same reference numerals.

The output signal of the monomultivibrator 36 whose output signal is inverted by the signal from the gate circuit 25 is supplied to one input terminal of the AND circuit 31 .

The synchronization separation circuit 38 separates the horizontal synchronization signal from the signal from the buffer circuit 31 and supplies it to the other input terminal of the AND circuit 37, and the output signal of the AND circuit 37 is supplied to the gate G of the FET transistor 39. There is.

The drain D of this FET) transistor 39 is grounded,
The source S is supplied with a signal from the buffer circuit 31 via resistors 40 and 41 in series.

The superimpose circuit 12 consists of an encoder 43 and a switch circuit 42, and the encoder 43 includes a buffer circuit 1.
It is used to demodulate RGB signals from 0r, 10g, and 10b into video signals. The switch circuit 42 is controlled by a signal from the gate circuit 25 and switches between the video signal from the encoder 41 and the signal obtained from the connection point of the resistors 40 and 41, and supplies the signal to the buffer circuit 14. There is.

Note that, in FIG. 2, a circuit for adjusting timing by using a burst flag pulse between the AND circuit 37 and the synchronization separation circuit 38 is not shown.

Here, a video signal of a still image is supplied to the input terminal 1, and the switch 26 is connected to the ground side. The output signal of the gate circuit 25 becomes high level, and the switch circuit 42
is connected to the d side, so an external video signal from the input terminal 28 or 29 is sent out from the output terminal 16 or 17.

At this time, since the output signal of the mono-multivibrator 36 is set to be at L level, the connection between the drain D and source S of the ET transistor 39 is open. Therefore, the external video signal is transmitted to the superimpose circuit 12 without reducing its level.

On the contrary, when the switch 26 is connected to the b side, the output port of the gate circuit 25 becomes a trubel, and the switch 42 is connected to the d side, so the still image from the input terminal 1 is output. A signal is sent out from output terminal 16 or 17.

Next, when a character video signal is supplied to input terminal 1, A
The ND circuit 13 detects a specific color, and the gate circuit 25
The output signal is at L level for the background part and at H level for the character part.

Therefore, the video signal of only the character part from input terminal 1 is
External video signals are connected to output terminals 16 on the back 1 and 1, respectively.
Or sent from 17.

At this time, the time constant of the inversion operation of the mono multivibrator 36 is set to approximately 2 fields, so the output signal is a torque signal. Therefore, the drain D and source S@ of the FET transistor 39 are closed, and the level of the external video signal is divided by the resistors 40 and 41 and transmitted to the superimpose circuit 12.

However, since the video signal synchronization period m includes pedestal level signals, burst signals, etc., it is necessary to lower the level.
Since there is a problem, the AND circuit 37 and the synchronous separation circuit 3
8 prevents the level of the video signal from dropping during the synchronization period.

In the above embodiment, the AND circuit 34 detects black, but if the voter is of a color other than black, the AND circuit 34 detects black.
By configuring an image frame color identification circuit in which blocks similar to comparators 9r, 9g, and 9b and latch circuits 11r, 11o, and 11b are added in front of the image frame color identification circuit, an arbitrary voter color can be detected.

(Effects of the Invention) According to the present invention, when a background part of a screen with text on a plain background is handled and a video is superimposed thereon from another video source, the level of the superimposed video is is automatically lowered, making it easier to read text on the display, and if the background color is a compact disc, the 4096 colors set by the digital code used for it will match the comparator value. Since it can be set accurately and freely by varying it, it has the advantage of being able to superimpose any background color.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the superimpose automatic level down device of the present invention, FIG. 2 is a detailed circuit diagram of the superimpose circuit 12 and half-down circuit 27, and FIG. , is a diagram for explaining an image frame (border) of a still image on a so-called compact disc used in the present invention. i, 28.29・, t terminal, 2r, 2C], 2b
. 10r, 10g, 10b, 14.31--buffer circuit, 3r, 3g, 3b・O-bus filter (L
PF), 4r, 4g, 4b...Analog-to-digital conversion circuit Δ/D conversion circuit>, 5r, 5g, 5b, 6r. 6o, 6b--Memory, 7r, 7g, 7b--Data selector, 8r, 8a, 8b...Digital-to-analog conversion circuit (D/Δ conversion circuit>, 9r, 9 (7, 9b...
・Magnitude comparator, 11r, 11g. 11b, 24...Latch circuit, 12...Superimpose circuit, 13.37...AND circuit, 15.2f
3.30...Switch, 16, 17...Output terminal,
18... Muting circuit, 19, 32.38...
Synchronous separation circuit, 20... Timing controller 1 to roll circuit, 21.42... Switch circuit, 22... Counter, 23... Delay circuit, 25... Gate circuit,
27... Half-down circuit, 33... Video signal detection circuit, 34... AND circuit (picture frame color identification circuit), 3
5... Microcomputer, 36... Mono multivibrator, 39... FET transistor, 40.
41...Resistor, 43 encoder.

Claims (1)

[Claims] When extracting the background color video signal from the first video signal corresponding to a screen with text on a plain background color and inserting another second video signal therein, the level of the second video signal is A superimpose automatic level down device that automatically downgrades RGB of the first video signal.
A magnitude comparator that compares each primary color signal with predetermined upper and lower limit values, a logic circuit that outputs a discrimination signal when the magnitude comparator discriminates a predetermined color, and a synchronization signal of the second video signal are separated. a synchronous separation circuit, a mono multivibrator whose output signal is inverted by the output signal of the logic circuit, an AND circuit that takes the logical product of the output signals of the mono multivibrator and the synchronous separation circuit, and an output signal of the AND circuit. a voltage dividing circuit which divides the level of the second video signal by being controlled by the voltage dividing circuit; an impose circuit, when the magnitude comparator determines the predetermined color in the first video signal, the superimpose circuit uses the voltage divider circuit to apply the synchronization signal to the predetermined color in place of the predetermined color. A superimpose automatic level down device characterized in that the voltage-divided second video signal is inserted for periods other than the period.