JPH0777438B2 - Imaging device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image pickup apparatus such as a television camera provided with a CCD solid-state image pickup device.

(B) Conventional technology In the case of the NTSC system, the playback screen of a general TV consists of 240 vertical pixels and 324 horizontal pixels per field, and at least an image sensor corresponding to the number of pixels is required to obtain this screen. Become. However, a solid-state image sensor with a large number of pixels
Since high integration is required, the manufacturing yield cannot be improved, resulting in high cost, resulting in high price of the TV camera.

Therefore, the applicant of the present invention has proposed an imaging device for enabling the use of a low-resolution solid-state imaging device with a small number of pixels in Japanese Patent Application No.
Proposed to No. 458. FIG. 4 is a block diagram showing the configuration of the image pickup device, and FIG. 3 is a timing diagram showing the operation.

Frame transfer CCD solid-state image sensor (1)
Is an image pickup unit (I), a storage unit (S), and a horizontal transfer unit (H)
The number of pixels of the image pickup unit (I) in the vertical direction and the number of pixels in the horizontal direction are each reduced to 1/2 of the normal element. For example, in case of NTSC system, vertical per field
It is formed with 120 pixels and 162 horizontal pixels. This CCD
(1) is pulse-driven by the transfer clock generation circuit (2), and has an image pickup section (I), a storage section (S), and a horizontal transfer section (H).
Are vertical transfer clock φ _I and storage transfer clock φ _{S, respectively.}
And a horizontal transfer clock φ _H. The transfer clock generation circuit (2) transfers transfer pulses φ _I , φ _S , to each part of the CCD (1) according to a timing signal created by the timing control circuit (3) based on the vertical scanning signal VD and the horizontal scanning signal HD. Supply φ _H.

Since the number of pixels in the vertical direction and the horizontal direction of the CCD (1) is half that of the normal CCD (1), when the information charges are read out and driven from the storage section (S) by the transfer pulse having the same period as the horizontal scanning signal HD. , I can only get 1/2 the number of horizontal scanning lines, and I cannot configure a TV screen. Therefore, the frequency of the accumulation transfer pulse φ _S and the horizontal transfer pulse φ _H is set to the frequency of the horizontal scanning signal HD.
It is halved. That is, the information charges are transferred from the storage section (S) to the horizontal transfer section (H) every 2H cycles. Therefore, the video signal X obtained from the CCD (1)
_{At 0 (t)} , a predetermined signal exists every 1H period. This video signal X _{0 (t)} is an intermittent signal in which there is a 1H period for every 2H period, and it is input to the interpolation circuit (4) to make this a continuous signal. The interpolation circuit (4) delays (4a) the video signal X _{0 (t)} for 1H period to obtain the video signal X _{1 (t)} , and the video signal X _{1 (t)} and the video signal X
By adding (4b ₎ with _{0 (t)} , a continuous video signal X _(t) is output every 1H period.

Such a video signal X _(t) is subjected to processing such as sample hold and amplification in the signal processing circuit (5) to become a video signal Y _(t) , which is supplied to the television monitor (6).

According to the above configuration, the horizontal scanning line of the playback screen is
A CCD with a small number of pixels can be used in a TV camera because the same signal can be obtained for every two lines.

(C) Problems to be Solved by the Invention Even in the above-described image pickup apparatus, it is possible to improve the horizontal resolution by interlacing the CCD (1), but the above-mentioned interpolation circuit ( The following inconveniences occur in the image pickup apparatus provided with 5).

That is, when imaging a subject as shown in FIG. 6 (a), first, in the odd field ODD, the areas of O1 to O3 are imaged, and O1, O1 to O3, O3 (solid lines) shown in FIG. In the next even field EVEN, the areas E1 to E3 are imaged and E1, E1 to E3, E3 (broken lines) shown in FIG. Therefore, as is clear from the figure, the position of each area may be reversed between the subject and the reproduction screen. For example, O2 for the subject
Is located above E2, while O2 appears on the playback screen.
An area located under E2 will occur. Therefore,
Despite the interlaced driving of CCD (1), the improvement of the image quality on the playback screen cannot be expected.

Therefore, it is an object of the present invention to provide an imaging device capable of obtaining a high-quality playback screen using a CCD having a small number of pixels.

(D) Means for Solving the Problem The present invention is for solving the above-mentioned problems, and an image is obtained by photoelectrically converting a received image having a vertical pixel number of 1/2 of a horizontal scanning line of a reproduction screen. A solid-state image sensor for obtaining information charges according to a pattern, vertically transferring the video signal by one horizontal line at intervals of one horizontal scanning period, and transferring the information charges transferred in the vertical direction horizontally by each horizontal line. Driving means for outputting, timing control means for setting the vertical transfer timing of the driving means by shifting one horizontal scanning period in odd field and even field, and setting the information charge on the output side of the solid-state image sensor for each pixel. The solid-state imaging device receives light by converting the value and outputting a video signal, and displaying information based on the video signal by non-interlaced scanning on the reproduction screen. The feature is that it reproduces the video.

(E) Operation According to the present invention, the video signal indicating the video information is obtained every other horizontal scanning period with a shift of one horizontal scanning period between the odd field and the even field, and this video signal is reproduced by non-interlaced scanning. Then, horizontal scanning lines of odd lines and even lines are alternately drawn for each field, and an image in which the horizontal scanning lines are arranged at equal intervals is displayed over the entire reproduction screen.

(F) Embodiment An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the image pickup apparatus of the present invention, and FIG. 2 is a timing diagram showing the operation.

The CCD solid-state image pickup device (10) includes an image pickup section (I) for receiving an image, a storage section (S) for sharing and storing information charges, and a horizontal transfer section (H) for transferring and outputting information charges row by row. As in FIG. 4, the number of pixels in the vertical direction and the number of pixels in the horizontal direction of the image pickup unit (I) are omitted at 1/2 of the reproduction screen. As a matter of course, the number of pixels of the storage unit (S) and the horizontal transfer unit (H) is omitted corresponding to the image pickup unit (I).

Transfer clock generation circuit (1
1) is composed of a vertical transfer clock generation circuit (11I), a storage transfer clock generation circuit (11S) and a horizontal transfer clock generation circuit (11H). Each unit of the CCD (10) has a vertical transfer clock φ _I storage transfer clock φ _S And a horizontal transfer clock φ _H , respectively. Each of these transfer clock generation circuits (11I)
(11S) (11H) are vertical sync signal VD and horizontal sync signal HD
The operation mode is inverted for each field. The vertical transfer clock generation circuit (11I) operates in accordance with the output of the storage mode switching circuit (12) which operates according to the field identification signal FLD, and during the storage period of the information charges, in the odd field ODD, the pixel of the (n-1) th row and the nth row. Mix the electric charge with the pixel, and in the even field EVEN, the pixel of the nth row and n +
A clock for applying a potential that mixes charges with the pixels in the first row to the image pickup unit (I) and transferring the information charges of the image pickup unit (I) to the storage unit (S) when a predetermined accumulation period elapses. To occur. In addition, the storage transfer clock generation circuit (11S)
A clock for receiving the information charges from the image pickup section (I) is generated, and a line feed pulse for transferring the received information charges to the horizontal transfer section row by row is generated. The timing of generating this line feed pulse is 1H in synchronization with the horizontal sync signal HD according to the output of the line feed timing generation circuit (13) which operates according to the field identification signal FLD and the horizontal sync signal HD.
It is set every other period during the blanking period of horizontal scanning, and it is 1 from even field EVEN in odd field ODD.
It will be sent for H periods and set. That is, since the information charges accumulated in the image pickup unit (I) in the even field EVEN are output from the accumulation unit (S) to the subsequent odd field ODD via the horizontal transfer unit (H), the (n-1) th row The signal corresponding to the charge obtained by mixing the pixel and the pixel in the n-th row is the pixel in the n-th row and n + 1.
The generation timing of the line feed pulse is 1H in the odd field ODD and the even field EVEN so that the signal corresponding to the charge mixed with the row pixel always precedes by 1H period.
Staggered for a period. Therefore, if the video signal X _(t) output from the CCD (10) has a signal indicating an image in the even number of horizontal scanning in the odd field ODD, the even field EVEN
Has a signal at an odd number of horizontal scanning.

Such a video signal X _(t) is subjected to processing such as sample hold and amplification in the video signal processing circuit (14) and then supplied to the television monitor (15) as a video signal Y _(t) . On this television monitor (15), the video signal Y _(t) is reproduced by non-interlaced scanning. Therefore, the TV monitor (1
On the reproduction screen of 5), horizontal scanning lines of odd-numbered rows are drawn in the first field, and horizontal scanning lines of even-numbered rows are drawn in the subsequent second field.

For example, when capturing an image of a subject as shown in FIG.
Regions O1 to O3 are imaged in the odd field ODD, and horizontal scanning lines are drawn as shown in FIG. 3 (a). At this time, the video signal Y _(t) generates a signal indicating the area of O1 to O3 in the odd-numbered horizontal scanning period, and O1 appears on the odd-numbered horizontal scanning lines.
Display the image in the area from ~ O3, and do not display anything on the horizontal scanning lines in the even rows. On the other hand, in the even field EVEN, E1-
An area E3 is imaged and a horizontal scanning line is drawn as shown in FIG. 3 (b). Since this horizontal scanning line is drawn by non-interlaced scanning, it coincides with the horizontal scanning line in FIG. The video signal Y _{(t) at} this time generates a signal indicating the area of E1 to E3 in the even-numbered horizontal scanning period and displays the image of the area of E1 to E3 on the horizontal scanning line of the even-numbered row. Then, nothing is displayed on the horizontal scanning line of the odd-numbered row. Therefore, the respective images of the subject are displayed on all the horizontal scanning lines on the reproduction screen in the two fields.

In the image pickup device as described above, the number of horizontal scanning lines itself is smaller than that in the case of interpolating the video signal X _(t) in units of 1H period, but the positional relationship of the video on the playback screen is opposite to that of the subject. This is not the case, and the intervals between the displayed horizontal scanning lines are uniform. By the way, even in the case of the image pickup apparatus as shown in FIG. 4, if the interpolation circuit (4) is omitted, the position of the image on the reproduction screen is not reversed, and the number of horizontal scanning lines is the same as in this embodiment. Although equal, the intervals of the horizontal scanning lines displayed on the reproduction screen become non-uniform, resulting in a difficult-to-see image.

Actually, in the NTSC type image pickup device, the number of horizontal scanning lines
Applicants confirmed that although 120, 240, and 480 were used, the apparent image quality difference between the case of 240 and the case of 480 was small, but the case of 120 clearly appeared to be worse than the case of 240. ing. Therefore, vertical 120 per field
If a CCD with pixels is used (NTSC compatible), CCD
By performing interlace driving for capturing an image and displaying the image on the reproduced image by non-interlaced scanning, 240 horizontal scanning lines can be obtained in the vertical direction, and thus it can be sufficiently used as a television camera.

In this embodiment, the frame transfer method is used.
Although the case where the CCD is used is shown as an example, the same operation is possible regardless of whether the CCD of the interline transfer method or the frame interline transfer method is used.

(G) Effect of the Invention According to the present invention, it is possible to obtain an easy-to-see reproduction screen by using a CCD whose number of pixels in the vertical direction and the horizontal direction is 1/2 of that of the reproduction screen. Can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of an image pickup apparatus of the present invention, FIG. 2 is a timing diagram of its operation, FIG. 3 is a schematic diagram of a playback screen, FIG. 4 is a block diagram of a conventional image pickup apparatus, and FIG. 5 is its operation. The timing chart and FIG. 6 are schematic diagrams of the subject and the reproduction screen. (1) (10) …… CCD solid-state image sensor, (2) (11) ……
Transfer clock generation circuit, (3) ... timing control circuit, (6) (15) ... TV monitor, (12) ... accumulation mode switching circuit, (13) ... line feed timing generation circuit.

Claims (2)

[Claims] 1. A solid-state image pickup device having a vertical pixel number of 1/2 of the number of horizontal scanning lines of a reproduction screen and photoelectrically converting a received image to obtain an information charge according to an image pattern. Driving means for transferring the generated information charges in the vertical direction for each horizontal line and transferring the information charges transferred in the vertical direction in the horizontal direction for each horizontal line, and the vertical transfer timing of the driving means. Timing control means for synchronizing with the horizontal scanning timing of the reproduction screen and shifting the horizontal scanning period by one horizontal scanning period between the odd-numbered vertical scanning period and the even-numbered vertical scanning period to set every other horizontal scanning period, The output side is provided with conversion means for converting the information charge into a voltage value for each pixel and outputting a video signal, and the information based on the video signal is displayed on the reproduction screen in an odd-numbered vertical scanning period. An image pickup apparatus which reproduces an image received by the solid-state image pickup device by displaying on the same horizontal scanning line during an even number of vertical scanning periods. 2. The image pickup apparatus according to claim 1, wherein the solid-state image pickup element is interlaced to invert the pixels storing the information charges in an odd field and an even field.