JP3373359B2 - Imaging device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for obtaining a video signal with high image quality.

[0002]

2. Description of the Related Art Televisions are known that the degree of modulation of a video signal of the current broadcasting system obtained by system conversion of a video signal of a high-definition imaging device is better than that of a video signal obtained by the current broadcasting system of the imaging device. Academic Technical Report vol.19, No.
26, PP65-69, the integrated production of high-definition television and the current broadcasting system using this technology has been put to practical use. In the conventional integrated production, the video signal format conversion is
This is done by connecting the imaging device and the format conversion device in series.

Hereinafter, a method for obtaining a video signal of a current broadcasting system using a conventional image pickup device and a system conversion device will be described with reference to FIGS.
Will be explained. In FIG. 3, reference numeral 30 shows a configuration of a video signal processing system of a conventional general high-definition image pickup apparatus. Reference numeral 301 denotes a solid-state image pickup device that picks up an image of a subject and performs photoelectric conversion. The obtained video signal is subjected to noise reduction and amplification processing by an analog signal processing circuit 302, and then a gamma correction circuit 303 changes the light emission characteristics of the monitor. Non-linear processing is performed for matching, and the color correction circuit 304 reproduces faithful colors. The contour correction circuit 305 filters the output of the gamma correction circuit 303 to extract high frequency components and generate a contour correction signal. The addition circuit 306 adds the color-corrected main line signal and the contour correction signal. Then, in order to generate the waveform of the video signal that can be displayed on the monitor, the blanking processing is performed by the blanking processing circuit 307,
The black clipping process and the white clipping process are performed by the clipping circuit 308, and the post-processing circuit 309 adds a synchronization signal to generate and output a high definition video signal.

Reference numeral 31 shows the configuration of a conventional system converter. The system conversion circuit 311 converts the high-definition video signal generated by the imaging device 30 into the current broadcasting system.
The conventional system conversion circuit 311 is known from the above-mentioned Television Society Technical Report vol. 19, No. 26, PP65-69 as an example of conversion from high-definition to the current broadcasting system. FIG. 4 shows a structure of a conventional system conversion circuit 311 based on such a case. A vertical direction interpolation processing circuit for generating 7 scanning lines from 15 scanning lines as vertical scanning lines. 40
1 converts 1035 to 483. The horizontal direction time axis conversion circuit 402 cuts the left and right regions in the edge crop mode, for example, and time-axis converts 1920 pixel samples into 754 pixel samples.
As a result, the aspect ratio of 16: 9 is converted to 4: 3. In these vertical and horizontal processes, the band is limited by the filter in order to reduce the aliasing noise, but the band limitation causes attenuation of the contour correction signal for high-definition. Therefore, the contour correction circuit 312 filters the output of the method conversion circuit 311 to extract high frequency components and generate a contour correction signal. Adder circuit 313
Adds the system-converted main line signal and the contour correction signal. In this way, the contour correction signal attenuated by the system conversion circuit 311 can be compensated. Then, in order to generate a video signal waveform that can be displayed on the monitor, blanking processing is performed by the blanking processing circuit 314, and black clipping processing and white clipping processing are performed by the clipping circuit 31.
5, the post-processing circuit 316 adds a synchronization signal to generate and output a video signal of the current broadcasting system. By converting the method of the output of the image pickup apparatus with such a configuration, it is possible to obtain a video signal having a larger degree of modulation than the image pickup apparatus of the current method.

The above principle will be described with reference to FIG. 5 showing the modulation characteristic of the image pickup apparatus and the method converter. FIG. 5 (a)
Shows the degree of modulation with respect to the horizontal resolution of the high-definition imaging device 30 and the current broadcasting system imaging device. According to this, the modulation degree of the high-definition imaging device at the same frequency is higher than that of the imaging device of the current broadcasting system. Further, FIG. 5B shows the degree of modulation with respect to the horizontal resolution of the system conversion device 31, and the system conversion device 3
In No. 1, since the contour correction is performed after the system conversion, the operation for increasing the modulation degree at the contour correction frequency is performed. Therefore, by multiplying the modulation degree characteristics of the high-definition imaging device and the format conversion device, it is possible to obtain a signal of the current broadcasting system having a large modulation degree.

[0006]

As described above, since the video signal which has been subjected to the gamma correction processing and the contour correction processing in the image pickup device is input to the system conversion device, the output signal of the system conversion device is It depends on gamma correction processing, color correction, and contour correction processing of the image pickup apparatus. Therefore, it is impossible to change the video signal waveform of the image pickup unit in a state where the video signal waveform of the system converter output is unchanged, and it becomes impossible to control the image quality independently of the high-definition and the current broadcasting systems. In actual operation, depending on the compatibility between the imaging device and the format conversion device, the knee and pedestal are adjusted in the high-definition imaging device so that the output of the format conversion device is not noticeable as white or black. Therefore, if the high-definition image pickup device is adjusted so that the output of the system conversion device is optimum, it becomes difficult to simultaneously achieve the image quality in both video signal formats. In such an image pickup device, it is necessary that a system converter is built-in so that output signals of high-definition and current broadcasting systems can be output at the same time, and image quality can be controlled independently.

In view of such a problem, the present invention provides an image pickup apparatus in consideration of the configuration of a system conversion apparatus, and realizes a wide range of image quality control by making the image quality of both video signal formats compatible with each other. It is an object.

[0008]

In order to achieve the above object, the image pickup apparatus of the present invention is provided with a means for performing video signal processing without system conversion in the video signal processing after photoelectric conversion, and a video signal after system conversion. When a processing means is provided, the processing method of both video signals can be selected as serial processing or parallel processing. Accordingly, both the video signal processing format without format conversion and the video signal format after format conversion can be output at the same time, and the image quality can be controlled independently, so that an image pickup apparatus capable of controlling a wide range of image quality can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is one in which a solid-state image pickup device or an image pickup tube is used to perform image pickup by photoelectric conversion, and gamma correction and color are performed without converting a video signal into another format. Means for performing video signal processing for correction and contour correction, means for performing video signal processing for gamma correction, color correction, and contour correction by converting the video signal into another format, and when not converting the video signal into another format And a means for selecting either serial processing or parallel processing of the video signal processing of 1) and the video signal processing performed by converting the video signal into a different format, and an image pickup apparatus according to claim 2 of the present invention. Of the present invention, means for performing analog signal processing on the signal output from the solid-state image sensor or the image pickup tube, means for quantizing the output signal of the analog signal processing means, and video signal for performing gamma correction, color correction and contour correction. A processing means, a means for selecting one of a signal before the video signal processing and a signal after the video signal processing, and a means for converting the output of the selection means. The image pickup apparatus according to claim 1, wherein in addition to conventional video signal processing, image quality can be made compatible by independent control of image quality of both video signal formats, so that a wide range of image quality control is realized. Have an effect.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

(Embodiment) FIG. 1 shows a configuration of an image pickup apparatus according to an embodiment of the present invention. In FIG. 1, 101 is a solid-state image pickup device that picks up an image of a subject and performs photoelectric conversion, 102 is an analog signal processing circuit that performs noise reduction and amplification processing of the obtained video signal, and 103 is video signal processing without system conversion. It is a preprocessing circuit as means for selecting either serial processing or parallel processing in the means and means for performing video signal processing after system conversion.
Reference numerals 104 to 110 constitute means A for performing video signal processing without format conversion, and 111 to 117 constitute means B for performing video signal processing after format conversion, respectively, similarly to the conventional example, the gamma correction circuits 104, 111. , Color correction circuits 105 and 112, contour correction circuits 106 and 113, addition circuits 107 and 114, and blanking processing circuit 10.
8 and 115, clip circuits 109 and 116, and post-processing circuits 110 and 117.

2A and 2B show different examples of the preprocessing circuit 103 in the above embodiment. In FIGS. 2A and 2B, 201 is the claim 2
Prinny circuit as an analog signal processing means in
Reference numeral 202 is an A / D conversion circuit as a quantization means, 203 is a switch circuit as a selection means for serial processing or parallel processing of video signals, and 204 is a system conversion circuit as a system conversion means. In FIG. 2A, since the input of the switch circuit 203 is a digital signal, an integrated circuit capable of simultaneously switching digital signals of a plurality of bits is preferable as the switch means in terms of downsizing.

The operation of this embodiment will be described below. In FIG. 1, the solid-state image sensor 101 images a subject, performs photoelectric conversion, and outputs a video signal. The obtained video signal is subjected to noise reduction and amplification processing in the analog signal processing circuit 102, and its output signal 102a is sent to the preprocessing circuit 103. The pre-processing circuit 103 can have two types of configurations shown in FIGS. 2A and 2B.
Is a gamma correction circuit A104 to a clipping circuit A109 as a video signal processing means and a gamma correction circuit B111.
In the case where the digital signal processing is performed from the clip circuit B116 to the clip circuit B116, (b) shows the gamma correction circuit B111 to the clip circuit B116 as the video signal processing means.
Up to digital signal processing. In FIG. 2A, the prinny circuit 201 performs an operation of compressing the video signal within the range of the number of input bits of the A / D conversion circuit 202. Output signal 103a of A / D conversion circuit 202
Is input to the gamma correction circuit A 104 and the switch circuit 203. The gamma correction circuit A104 performs non-linear processing for display on the monitor, and the color correction circuit A105 faithfully reproduces the main line color. Contour correction circuit A10
Reference numeral 6 filters the output of the gamma correction circuit A104 to extract high frequency components and generate a contour correction signal. The adder circuit 107 adds the color-corrected main line signal and the contour correction signal. Then, in order to generate a high-definition video signal waveform that can be output to the monitor, blanking processing is performed by the blanking processing circuit A108, and black clipping and white clipping processing is performed by the clipping circuit A109. The above processing is the same as that of the conventional image pickup apparatus, but the video signal 10 of the clip circuit A109 is changed.
By inputting 9a into the pre-processing circuit 103, the system conversion is performed after the conventional high-definition video signal processing, and the system conversion process is performed before the high-definition video signal processing to perform the video signal processing by the current broadcasting system. You can choose either.

The switch circuit 203 as a video signal selection means in FIG. 2A selects the video signal 109a output from the clip circuit A109 in the state shown in the figure, and after performing the high-definition video signal processing. The system conversion circuit 204 converts the video signal format to the current broadcasting system and performs video signal processing. The video signal processing for the output signal 103b of the system conversion circuit 204 is performed from the gamma correction circuit A104 to the clipping circuit A.
The operation is the same as that up to 109. That is, gamma correction circuit B
In 111, a non-linear process for displaying on a monitor is performed, and in the color correction circuit B112, the color of the main line system is faithfully reproduced. The contour correction circuit B113 is a gamma correction circuit B11.
By filtering the output of 1, the high frequency component is extracted and the contour correction signal is generated. The adder circuit 114 adds the color-corrected main line signal and the contour correction signal. Then, in order to generate the waveform of the video signal of the current broadcasting system which can be displayed on the monitor, the blanking process is performed by the blanking process circuit B115, and the black clip process and the white clip process are performed by the clip circuit B116. This video signal processing also has a processing procedure similar to that of the conventional technique, and it is possible to output a video signal of the current broadcasting system after adding a high-definition contour correction signal.

On the other hand, when the switch circuit 203 as a video signal selecting means operates so as to directly input the output signal of the A / D conversion circuit 202 to the system conversion circuit 204, the video signal processing without system conversion is performed. The processing system from the gamma correction circuit A104 to the post-processing circuit A110 as means and the processing system from the gamma correction circuit B111 to the post-processing circuit B117 as the video signal processing means after system conversion are independent processing. The video signals processed by both systems are processed in parallel. Therefore, since the signal waveform of the current broadcasting system whose format has been converted does not depend on the signal waveform of high-definition television without system conversion, it is possible to achieve both high-definition and current broadcasting image quality, and independent image quality control is also possible. .

In the case where the preprocessing circuit 103 has the configuration shown in FIG. 2A, the postprocessing circuit A110 and the postprocessing circuit B11.
7 is D / A conversion for both digital video signals,
Add a sync signal. In addition, the preprocessing circuit 103 is shown in FIG.
In the case of the configuration of (b), since the input of the post-processing circuit A110 is an analog signal, only the operation of adding the synchronizing signal to the input signal is performed, and the post-processing circuit B117 receives the digital signal, so that the D / A conversion is performed. And add sync signal. The configuration of FIG. 2B is a case where the signal input to the switch circuit 203 as the signal selecting unit is analog, and the operation is the same as that of FIG. 2A. Further, the above-described embodiment is a case where the high-definition video signal is system-converted into the current system, but the present invention is not limited to this and can be applied to other video signal formats.

[0017]

As described above, according to the present invention, the video signal processing in the video signal format without system conversion and the video signal processing after system conversion can be selected as either serial processing or parallel processing. Therefore, in serial processing, video signal processing without system conversion can be reflected to perform video signal processing after system conversion, and in parallel processing, image quality can be controlled independently for each video signal format. It is possible to achieve both of them, and it is possible to obtain an advantageous effect that a wide range of image quality can be controlled.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an imaging device according to an embodiment of the present invention.

2A and 2B are block diagrams showing details of a preprocessing circuit in the same apparatus.

FIG. 3 is a block diagram showing a configuration of a video signal processing system according to a conventional technique.

FIG. 4 is a block diagram showing a configuration of a conventional system converter.

5A and 5B are characteristic diagrams showing modulation degree characteristics of an imaging device and a system converter.

[Explanation of symbols]

101 Solid-state image sensor 102 analog signal processing circuit 103 Pre-processing circuit 104 Gamma correction circuit A 105 Color correction circuit A 106 contour correction circuit A 107 adder 108 Blanking processing circuit A 109 Clip circuit A 110 Post-processing circuit A 111 Gamma correction circuit B 112 Color correction circuit B 113 Contour correction circuit B 114 adder 115 Blanking processing circuit B 116 Clip circuit B 117 Post-processing circuit B 201 Pliny circuit 202 A / D conversion circuit 203 switch circuit 204 system conversion circuit

Claims (2)

(57) [Claims] 1. A means for performing video signal processing of gamma correction, color correction and contour correction without performing conversion of a video signal into another format by performing imaging by photoelectric conversion using a solid-state imaging device or an image pickup tube, and a video. A means for performing video signal processing such as gamma correction, color correction, and contour correction by converting the signal to another format, and video signal processing when the video signal is not converted to another format and the video signal to another format. An image pickup apparatus having means for selecting either serial processing or parallel processing as the video signal processing to be performed. 2. A means for performing analog signal processing on a signal output from a solid-state image sensor or a pickup tube, means for quantizing an output signal of the analog signal processing means, and video for performing gamma correction, color correction and contour correction. A signal processing means, means for selecting one of a signal before performing the video signal processing and a signal after performing the video signal processing, and means for converting the output of the selecting means. Claim 1
The imaging device described.