JPH07131815A - Video camera - Google Patents

Abstract

PURPOSE:To automatically improve color reproducibility by discriminating a discharge lamp light source which is inferior in color deduction such as a mercury vapor lamp and a low-pressure sodium lamp. CONSTITUTION:A photosensor 11 photodetects light which is inputted through a camera lens 1 and the photodetected light is photoelectrically converted and outputted to an AC decision part 12. The AC decision part 12 outputs a decision result showing whether the input signal is AC to a color compensation control part 13, which decides that the light source is not a discharge lamp when the decision result indicates DC and performs no special color compensation, but decides that the light source is the discharge lamp when the decision result indicates the AC and outputs a hue and saturation degree control signal for color compensation to a matrix circuit 6, thereby improving the color reproducibility in case of the discharge lamp light source which is inferior in color deduction such as the mercury vapor lamp and low-pressure sodium lamp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to stores, factories, buildings,
The present invention relates to a video camera for video monitoring that monitors a station, a road, etc. by video, and particularly to improvement of color reproducibility in a discharge lamp light source.

[0002]

2. Description of the Related Art Conventionally, there is an example shown in Japanese Patent Laid-Open No. 7369/1993 as a light source discrimination for improving the color reproducibility of a video camera in a discharge lamp light source such as a fluorescent lamp or a mercury lamp. The illumination light source is determined based on the value of the balance control signal that has converged. FIG. 11 is a configuration diagram showing a conventional video camera. In the figure, 1 is a camera lens for forming an image of an object on an image forming surface, 2 is an image pickup device for photoelectrically converting an image formed by the camera lens 1, Reference numeral 3 denotes a video signal from the image sensor 2 and a luminance signal Y and red, blue,
A color separation circuit for separating the green color signals R, G, and B, a luminance signal processing circuit 4 for performing aperture correction and gamma correction on the luminance signal Y, and a reference numeral 5 for changing the gains of the red signal R and the blue signal B. A white balance circuit, 6 represents white-balanced color signals R, G, B and color difference signals RY, BY
The matrix circuit 7 converts the luminance Y and the color difference signal R-
An encoding circuit for converting Y and BY into a composite color video signal, 8 an integrating circuit for integrating the color difference signals RY and BY, and 9 based on an integrated value of the color difference signals RY and BY. The white balance control unit 10 for calculating the gain control values of red and blue in the white balance circuit 5 determines the type of illumination light source from the white balance convergence value from the white balance control unit 9 to determine the color difference R of the matrix circuit 6.
It is a color compensation control unit that controls the hue and saturation of -Y and BY.

Next, the operation will be described. The subject imaged on the photoelectric conversion surface of the image sensor 2 by the camera lens 1 is photoelectrically converted by the image sensor 2 to be a video signal. Image sensor 2
A luminance component and a color component are superimposed on the output video signal, and are separated into a luminance signal Y and color signals R, G, B by the color separation circuit 3. The brightness signal Y is subjected to processing such as aperture correction and gamma correction in the brightness signal processing circuit 4. Color signal R,
G and B are white-balanced by adjusting the gains of red and blue by the white balance circuit 5, and converted into color difference signals RY and BY by the matrix circuit 6. The luminance signal Y from the luminance signal processing circuit 4 and the matrix circuit 6
The color difference signals R-Y and B-Y from are converted by the encoding circuit 7 and output as a composite color video signal. Matrix circuit 6 output color difference signals RY and BY
Are integrated by the integrating circuit 8 in units of one field. The white balance control unit 9 adjusts the red and blue signal gains so that the colors of the entire screen are averaged from the integrated color difference signals R-Y and B-Y from the integration circuit 8 so as to be achromatic. When the white balance control unit 9 performs white balance, the color compensation control unit 10 determines the type of the illumination light source from the white balance convergence value of the white balance control unit 9, that is, the color temperature, and determines the color difference RY, B of the matrix circuit 6. Control the hue and saturation of Y.

Further, as an example in which a photo sensor is used to determine an illumination light source, there are examples shown in Japanese Patent Application Laid-Open No. 2-46090 and Japanese Patent Application Laid-Open No. 2-30287. If the converted electric signal contains an AC component, it is determined that the illumination light source is a discharge lamp.

[0005]

Since the conventional video camera is constructed as described above, it is disclosed in JP-A-5-7369.
In the case of the example of the publication, since the type of the illumination light source is determined only by the color temperature of the illumination light source, even if the emission spectra are different, if the color temperatures are similar, it cannot be correctly determined and the color compensation Can't be right. In addition, Japanese Patent Laid-Open No. 2-4
In the case of the examples of JP-A-6090 and JP-A-2-30287, there is a problem that a photo sensor must be provided at each subject when a zoom camera lens or a turntable is attached to the camera.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a video camera capable of accurately performing illumination light source determination and appropriate color compensation.

[0007]

A video camera according to the present invention is a camera lens for forming an image of an object on an image forming surface,
An image sensor that photoelectrically converts the imaged subject, a color separation unit that separates the signals of the three primary colors of red, blue, and green and luminance from the output signals of the image sensor, white balance by controlling the gain of the red and blue signals. White balance adjusting means for adjusting, color difference signal calculating means for calculating and outputting a color difference signal from the three primary colors output with white balance, integrating means for integrating the output of the color difference signal calculating means, and controlling the white balance adjusting means by the output of the integrating means In a video camera equipped with white balance control means, a photosensor for photoelectrically receiving light that has passed through the camera lens, an AC discrimination means for discriminating the presence or absence of an AC component of the light received from the output of the photosensor, and an AC discrimination means Color compensation for controlling at least one of the hue and the color saturation of the color difference of the color difference signal calculation means by the output It is those with a control means.

In the AC discrimination means, the output signal of the photosensor is sampled at a cycle sufficiently shorter than the power supply cycle of the illumination light source, the cycle being close to half the power supply cycle, and the maximum sampling value. When the difference between the minimum value and the minimum value is larger than the threshold value, the illumination light source determines the AC component as including the AC component.

Further, in the above video camera, a photo sensor is provided between the lens groups of the camera lenses.

Further, a plurality of photoelectric conversion units, each of which has a plurality of photoelectric conversion elements arranged in a fixed direction in the image pickup pixel unit, and a vertical register unit which receives the output of the photoelectric conversion unit and shifts the image pickup pixel unit, are arranged in pairs. A photosensor is integrated with an image pickup device having a horizontal register unit that is input in parallel from the vertical register unit and is shifted in image pickup pixel units, and a voltage is always output according to the amount of light received by the image pickup device.

Further, the video camera is provided with a timing generating means for causing the image pickup device to perform a high-speed shutter operation at the time of determining the illumination light source, and determines whether or not there is an AC component of the light received from the output when the high-speed shutter operation is performed. It is to determine.

[0012]

In the video camera according to the present invention, the AC discriminating unit detects the AC component from the light received by the photosensor through the camera lens, and if there is the AC component, the illumination light source is discriminated as a discharge lamp, and the illumination light source is determined. If it is a discharge lamp, it is a matrix circuit that converts red, blue, and green signals into color difference signals, and one or both of hue and saturation is adjusted by the control of the color compensation control unit to perform color compensation. is there.

Further, the output signal of the photosensor is sampled at a cycle sufficiently shorter than the power supply cycle of the illumination light source, and the presence or absence of the AC component of the illumination light source is surely determined.

Further, since the photo sensor is built in the camera lens, the subject itself being imaged can be measured, so that the illumination light source at the place where the image is taken can be more accurately determined.

Further, since the solid-state image pickup device and the photosensor are integrally formed, the solid-state image pickup device is always operated in accordance with the amount of received light.
The AC component of the illumination power supply can be accurately determined.

Further, at the time of determining the illumination light source, the image pickup device performs a high-speed shutter operation under the control of the timing generation means, and the presence or absence of the AC component of the illumination light source is determined by sampling the received light.

[0017]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to FIG.
Will be described. In the figure, 1 is a camera lens for forming an image of a subject on an image forming surface, 2 is an image pickup device for photoelectrically converting an image formed by the camera lens 1, and 3 is a video signal from the image pickup device 2 as a luminance signal Y. A color separation circuit for separating red, blue, and green color signals R, G, and B, 4 is a brightness signal processing circuit for performing aperture correction and gamma correction on the brightness signal Y, and 5 is a red signal R and a blue signal B. White balance circuit that adjusts the white balance by changing the gain of 6
Is a matrix circuit which is a color difference signal calculating means for converting the white-balanced color signals R, G, B into color difference signals RY, BY, and 7 is a composite color of the luminance Y and the color difference signals RY, BY. Encoding circuit that converts to video signal,
8 is an integrating circuit for integrating the color difference signals R-Y and BY, and 9 is a gain control value for red and blue in the white balance circuit 5 based on the integrated value of the color difference signals R-Y and BY. A white balance control unit, 11 is a photo sensor that receives light that has passed through the camera lens 1 and photoelectrically converts it, and 12 inputs the output from the photo sensor 11 and determines the presence or absence of an AC component and outputs an AC discrimination signal. An AC discriminating unit 13 discriminates the discharge lamp component of the illumination light source from the AC discriminating signal from the AC discriminating unit 12 to control the hue and saturation of the color differences RY and BY of the matrix circuit 6 and a color compensation control unit. Is.

FIG. 2 is a diagram showing a place where the photo sensor 11 is arranged. The figure shows the image sensor 2 from the camera lens 1 side.
2 is an image sensor, 14 is a package for holding the image sensor 2, 15 is a window for allowing light to pass through the image sensor 2, and 16 is light incident through which light enters through the camera lens 1. Area. The photo sensor 11 has a light entering area 1
It is located within 6 and does not create a shadow on the image sensor 2.

Next, the operation will be described. The subject imaged on the photoelectric conversion surface of the image sensor 2 by the camera lens 1 is photoelectrically converted by the image sensor 2 to be a video signal. Image sensor 2
The luminance signal and the color component are superimposed on the video signal which is the output of the luminance signal Y, the color signals R, G and B in the color separation circuit 3.
Is separated into The brightness signal Y is subjected to processing such as aperture correction and gamma correction in the brightness signal processing circuit 4. For the color signals R, G, B, the white balance circuit 5 adjusts the red and blue gains to obtain white balance,
The matrix circuit 6 converts the color difference signals RY and BY. The luminance signal Y from the luminance signal processing circuit 4 and the color difference signals RY and BY from the matrix circuit 6 are converted by the encoding circuit 7 and output as a composite color video signal. The color difference signal RY of the matrix circuit 6 output,
BY is integrated by the integrating circuit 8 in units of one field. The white balance control unit 9 adjusts the red and blue signal gains so that the colors of the entire screen from the integrated color difference signals R-Y and B-Y from the integrating circuit 8 are achromatic. Based on the output from the photo sensor 11, the AC determination unit 12 determines the presence or absence of an AC component in the illumination light source.

The color compensation control unit 13 does not perform color compensation when the light source is not a discharge lamp. Hue control values and saturation control values of color differences RY and BY, and color when the light source is a discharge lamp. When the determination result from the AC determination unit 12 includes the hue control value and the saturation control value of the color differences RY and BY for performing the compensation and the AC component does not exist, the color compensation is not performed. R
The hue control values and saturation control values of −Y and BY are output to the matrix circuit 6, and when the determination result indicates that there is an AC component, the color differences RY and BY for performing color compensation are calculated. The hue control value and the saturation control value are output to the matrix circuit 6.

The operation of the AC discriminating unit 12 will be described. FIG. 3 is a diagram showing how the photosensor 11 receives light. The horizontal axis represents time, the vertical axis represents the amount of light incident on the photosensor 11,
The output voltage of the photo sensor 11 is proportional to the amount of incident light. The output voltage of the photo sensor 11 has a cycle that is 0.5 times the power cycle of the illumination light source. In the AC determination unit 12, the output signal of the photo sensor 11 is sampled at a cycle sufficiently shorter than the power supply cycle, the cycle is close to half the power supply cycle, and the difference between the maximum value and the minimum value of the sampling values is the threshold value. Since the illuminating light source contains an AC component when the value is larger than that, it is determined that the illuminating light source is a discharge lamp. From the above,
The AC discrimination unit 12 determines the illumination light source based on the presence or absence of the AC component of the illumination light source, and the color compensation control unit 13 determines the color difference R− of the matrix circuit 6 based on the determination result of the AC determination unit 12.
It is possible to surely perform color compensation by controlling the hues and color saturations of Y and BY.

Example 2. FIG. 4 is a diagram illustrating an embodiment in which a photo sensor 11 for discriminating an illumination light source is provided inside a camera lens. In the figure, 17 is a camera lens equipped with a photo sensor, and 18 is a camera lens 1 respectively.
Reference numeral 11 is a lens that constitutes 7, a light path of an object, and 11 is a photo sensor. The photo sensor 11 is a camera lens 18
The light from the subject is received in the optical path 19 inside the. The configuration and operation of the video camera are the same as those in the first embodiment. Is the same as. As described above, since the camera lens has a built-in photo sensor, it is possible to measure the imaged subject itself, so that it is possible to more accurately determine the illumination light source and more reliably perform color compensation.

Example 3. A third embodiment of the solid-state image sensor including a photosensor that constantly outputs a photoelectric conversion voltage according to the amount of received light will be described. FIG. 5 is a diagram showing the structure of this solid-state image pickup device, in which 20 is a solid-state image pickup device including a photosensor, 21 is a photoelectric conversion device for each image pickup pixel arranged in a vertical direction for image pickup, and a horizontal direction is shown. Further, a photoelectric conversion unit 22 is further arranged, a vertical shift register unit 22 that inputs the output of the photoelectric conversion unit 21 in parallel for each column, and shifts in an image pickup pixel unit, and a vertical shift register unit 2 23.
A horizontal shift register unit for parallel input from 2 and shifting for each imaging pixel unit, a photosensor unit for constantly outputting a photoelectric conversion voltage according to the amount of received light, and a light incident unit for receiving light through the camera lens 1. Area.

The operation will be described. In the operation for imaging, the light formed by the camera lens 1 in the photoelectric conversion unit 21 is accumulated for one field. The charges accumulated in the photoelectric conversion unit 21 during the vertical blanking period are moved to the vertical shift register unit 22 in parallel. The charges in the vertical shift register unit 22 are moved in parallel to the horizontal shift register 23 by one row in each horizontal period within the horizontal blanking period. The horizontal shift register 23 outputs charges in pixel units. on the other hand,
The photo sensor unit 24 always photoelectrically converts the incoming light and outputs a voltage proportional to the incoming light without accumulating.

FIG. 6 is a diagram showing a structure of a video camera using a solid-state image pickup device having a photosensor which always outputs a photoelectric conversion voltage according to the amount of the received light. It is a solid-state image sensor including a sensor, and other configurations are the same as those in the first embodiment. Is the same as. Also, regarding the operation, the first embodiment will be described. Is the same as. As described above, by integrating the photo sensor with the image sensor,
It is not necessary to provide it separately from the image pickup element, and the video camera can be downsized, which is advantageous in terms of cost.

Example 4. A fourth embodiment in which the illumination light source is determined by changing the operation of the image sensor will be described. FIG. 7 is a view showing this structure. In the figure, 1 is a camera lens for forming an image of a subject on an image forming surface, 2 is an image pickup element for photoelectrically converting an image formed by the camera lens 1, and 3 is an image pickup element. A color separation circuit 4 for separating a video signal from the image pickup device 2 into a luminance signal Y and red, blue, and green color signals R, G, and B is a luminance signal Y.
A luminance signal processing circuit for performing aperture correction and gamma correction, 5 is a white balance circuit for changing the gains of the red signal R and the blue signal B, and 6 is a color difference signal R for the white-balanced color signals R, G, B A matrix circuit for converting into -Y and BY, 7 is a luminance Y and color difference signals RY and B-
An encoding circuit for converting Y into a composite color video signal, 8 an integrating circuit for integrating the color difference signals RY and BY, and 9 a white balance circuit 5 based on the integrated value of the color difference signals RY and BY. White balance control section for calculating the red and blue gain control values, 25 is a timing generation circuit for controlling the operation of the image sensor 2, and 26 is the image sensor 2.
An AC discriminating unit for inputting the output from the discriminating unit and discriminating the presence or absence of an AC component and outputting an AC discriminating signal, 13 discriminates the discharge lamp component of the illumination light source from the AC discriminating signal from the AC discriminating unit 12, and determines the matrix circuit 6 Is a color compensation control unit that controls the hue and saturation of the color differences R-Y and B-Y.

The operation will be described. During image pickup, the image pickup element 2 operates normally under the control of the timing generation circuit 25. Timing determination circuit 25 for illumination light source determination
The image sensor 2 performs a high-speed shutter operation under the control of.
The received light is sampled by performing the high-speed shutter operation, and the presence / absence of the AC component of the illumination light source is determined by this. Others are the same as in Example 1. It is the same operation as. As described above, the photosensor is not necessary, and the solid-state imaging device receives light by the high-speed shutter operation, and the light is sampled, whereby the illumination light source can be determined.

Example 5. FIG. 8 is a diagram for explaining another embodiment of mounting the photo sensor 11 for discriminating the illumination light source. The figure is a view of the image sensor 2 from the camera lens 1, in which 2 is an image sensor and 14 is an image sensor 2.
, 15 is a window for allowing light to pass through the image pickup element 2, and 16 is a light incident area where light is incident through the camera lens 1. Reference numeral 27 denotes an optical fiber cable having an incident light port in the light incident area 16 and arranged at a position where no shadow is formed on the image pickup element 2. The photo sensor 11 is attached to the emission light port of the optical fiber cable 27. The light of the light incident area 16 guided by the optical fiber cable 27 is incident on the photo sensor 11. Example 1 except that the light is guided to the photo sensor 11 by the optical fiber cable 27. Is the same as.

Example 6. FIG. 9 is a diagram for explaining another embodiment in which the photo sensor 11 for discriminating the illumination light source is attached. The figure is a view of the camera lens 1 and the image pickup device 2 as seen from the side. In the drawing, 1 is a camera lens, 2 is an image pickup device, 14 is a package for holding the image pickup device 2, and 15 is light passing through the image pickup device 2. Window 28 for camera lens 1
Is an incident optical path through which light is incident. Reference numeral 29 is a mirror which is located in the incident optical path 28 and is arranged at a position where it does not form a shadow on the image sensor 2. The photo sensor 11 is attached to the reflection optical path of the mirror 29. Part of the light of the incident light path 28 guided by the mirror 29 is incident on the photosensor 11. Other than mounting the photo sensor 11,
This is the same as in the first embodiment.

Example 7. FIG. 10 is a diagram for explaining another embodiment of mounting the photo sensor 11 for discriminating the illumination light source. The figure is a side view of the camera lens 1 and the image sensor 2. In the figure, 1 is a camera lens, 2 is an image sensor, 14 is a package for holding the image sensor 2, and 1 is a package.
Reference numeral 5 is a window for allowing light to pass through the image sensor 2, and 28 is an incident optical path on which light is incident through the camera lens 1. Reference numeral 30 is a half mirror that is in the incident optical path 28 and covers the entire surface of the image pickup element 2. The photo sensor 11 is attached to the reflection optical path of the half mirror 30. The light on the entire surface of the incident optical path 28 guided by the half mirror 30 is incident on the photosensor 11. The reflectance and the transmittance of the half mirror 30 are set sufficiently high so that the sensitivity of the video camera does not deteriorate. The procedure is the same as that of the first embodiment except that the photo sensor 11 is attached.

Example 8. Example 2. Then, the photo sensor was directly inserted in the optical path of the camera lens, but in Example 5,
As in 6 and 7, an optical fiber cable, a mirror or a half mirror may be used.

Example 9. Example 3. In the solid-state image sensor, a photosensor for detecting the AC component of the illumination light source is provided adjacent to the photoelectric conversion unit for imaging, but the AC of the illumination light source is included in the region of the photoelectric conversion unit for imaging. Photosensors for detecting the components may be scattered.

[0033]

As described above, according to the present invention, the light passed through the camera lens is received by the photo sensor, and it is determined whether the illumination light source is a discharge lamp or not based on the presence or absence of the AC component of the output of the photo sensor. With this configuration, it is possible to accurately determine the illumination light source at the place where the image is captured, and to reliably perform color compensation.

Further, since the camera lens has a built-in photo sensor, it is possible to measure the subject itself being imaged, so that the illumination light source at the place where the image is captured can be determined more accurately, and color compensation can be performed more reliably. effective.

Further, since it is not necessary to integrate the photosensor with the image pickup element and separately provide the photosensor, the video camera can be downsized and the cost can be reduced.

Further, there is an effect that the photoelectric conversion function of the image pickup device can be operated by the high-speed shutter to correctly determine the illumination light source without providing the photo sensor, and the color compensation can be surely performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video camera according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of photosensors according to the first embodiment of the present invention.

FIG. 3 is a diagram showing output waveforms of a discharge lamp illumination light source and a photo sensor.

FIG. 4 is a block diagram showing a configuration of a camera lens of a video camera according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a solid-state image sensor according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a video camera according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a video camera according to a fourth embodiment of the present invention.

FIG. 8 is a view showing the arrangement of photosensors when an optical fiber cable according to another embodiment 5 of the present invention is used.

FIG. 9 is a diagram showing an arrangement of photosensors when a mirror according to a sixth embodiment of the present invention is used.

FIG. 10 is a diagram showing an arrangement of photosensors when a half mirror according to a seventh embodiment of the present invention is used.

FIG. 11 is a block diagram showing a configuration of a conventional video camera.

[Description of Reference Signs] 1, 17 Camera lens 2 Image sensor 3 Color separation circuit 4 Luminance signal processing circuit 5 White balance circuit 6 Matrix circuit 7 Encoding circuit 8 Integration circuit 9 White balance control unit 10, 13 Color compensation control unit 11 Photo sensor 12, 26 AC determination unit 14 Package 15 Window 16 Light incident area 18 Lens 19 Optical path 20 Solid-state image sensor 21 Photoelectric conversion element 22 Vertical shift register section 23 Horizontal shift register section 24 Photosensor section 25 Timing generation circuit 27 Optical fiber cable 28 Incident optical path 29 Mirror 30 Half mirror

Claims (5)

[Claims] 1. A camera lens for forming an image of an object on an image forming surface, an image sensor for photoelectrically converting the imaged object, and a red, blue, and green primary color signal and a luminance signal are separated from output signals of the image sensor. Color separation means, white balance adjustment means for controlling white balance by controlling gains of red and blue signals, color difference signal calculation means for calculating and outputting color difference signals from the three primary colors output after white balance, and output of color difference signal calculation means In a video camera equipped with an integrating means for integrating the white balance adjusting means for controlling the white balance adjusting means by the output of the integrating means, a photo sensor for photoelectrically receiving light passing through the camera lens, and a light received from the output of the photo sensor. An AC discrimination unit that discriminates the presence or absence of an AC component of light, and the color of the color difference of the color difference signal calculation unit by the output of the AC discrimination unit A video camera comprising color compensation control means for controlling at least one of phase and color saturation. 2. The AC discriminating means samples the output signal of the photosensor at a cycle of the received light which is sufficiently shorter than the power cycle of the illumination light source, and the cycle is close to half of the power cycle and the maximum sampling value is obtained. The video camera according to claim 1, wherein when the difference between the minimum value and the minimum value is larger than a threshold value, the illumination light source determines the AC component as including the AC component. 3. The video camera according to claim 1, wherein a photo sensor is provided between the lens groups of the camera lenses in the video camera. 4. A plurality of photoelectric conversion elements, each of which has a plurality of photoelectric conversion elements arranged in an image pickup pixel unit in a fixed direction, and a vertical register section which receives the output of the photoelectric conversion section and shifts the image pickup pixel unit. A photosensor is integrated with an image pickup device having a horizontal register unit that is input in parallel from the vertical register unit and shifts in image pickup pixel units, and a voltage is constantly output according to the amount of light received by the image pickup device. The video camera according to claim 1. 5. The video camera includes timing generation means for causing an image sensor to perform a high-speed shutter operation when determining an illumination light source, and determines whether or not there is an AC component of light received from an output when the high-speed shutter operation is performed. The video camera according to claim 1, wherein the video camera discriminates.