JPH0546759B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention obtains an imaged color signal output in a state in which two or more primary color signal components are mixed and performs signal processing using a so-called separate luminance method. The present invention relates to a color video camera that outputs a standard television signal of a desired format.

[Conventional technology]

Generally, in a color video camera, a stripe-like or mosaic-like color coding filter is arranged in front of the imaging surface of the image pickup tube or solid-state image sensor, and the color coding filter converts the imaging light into three primary color components R. , G, and B to perform color imaging, and a primary color signal and a luminance signal are generated from the imaging output.

In color video cameras, the color tone of the reproduced image changes depending on the color temperature of the imaging light source, so in order to obtain color imaging output with good color reproducibility, the color tone of the reproduced image changes depending on the color temperature of the imaging light source. It is necessary to adjust the white balance accurately.

Conventionally, white balance adjustment has been carried out by photographing a reference white subject under the color temperature of a certain imaging light source, and adjusting the signal level R of the red component, the signal level R of the green component, and the signal level of the blue component of the imaging output. This was done by setting level adjustment circuits provided for each color signal line so that the ratio of B was R:G:B=1:1:1. For example, as disclosed in Japanese Patent Publication No. 56-4993, there is also a white balance adjustment device that constantly detects the color temperature of an imaging light source and follows changes in the color temperature over time. Proposed.

In addition, conventionally, imaging light has been changed to yellow, e.g.
A complementary color coding filter that separates colors into complementary color components such as cyan Cy and magenta Mg is arranged in front of the imaging surface of the image sensor to perform color imaging and form a primary color signal and a luminance signal from the imaging output obtained. A color video camera using complementary color coding has been proposed. In this color video camera using complementary color coding, signal processing corresponding to the so-called separated luminance method is performed to directly form a luminance signal from the imaged color signal output which is a mixture of a plurality of primary color components obtained by the image sensor. Accordingly, it is possible to improve imaging sensitivity, S/N, etc.

By the way, as mentioned above, in a color video camera that uses a complementary color coding filter, signal processing corresponding to the so-called separation brightness method is performed to output an imaged color signal in a state in which multiple primary color components obtained by an image sensor are mixed. For example, when forming luminance signals and color signals compatible with the NTSC system, errors occur in the luminance reproducibility of reproduced images due to differences in the color temperature of the imaging light source, so R = G when achromatic.
It is not possible to capture a faithful color image of the subject image simply by adjusting the white balance of the color signal processing system so that =B. It is also necessary to perform level balance adjustment on the imaging color signals.

[Problem that the invention seeks to solve]

By the way, as mentioned above, in a color video camera that uses a complementary color coding filter, the image sensor outputs a color signal that is a mixture of multiple primary color components, and performs signal processing that corresponds to the separation brightness method. When forming signals and luminance signals, it is necessary to provide level balance adjustment means for each of the color signal processing system and the luminance signal processing system, and if each adjustment means is automatically controlled, the configuration becomes extremely complicated. I had a problem with it getting hot.

Therefore, in view of the above-mentioned problems, the present invention has been made to
In a color video camera that obtains an imaged color signal output in a state where two or more primary color signal components are mixed from a color image sensor, performs signal processing using a so-called separate luminance method, and outputs a standard television signal of a desired method. A function that automatically adjusts the white balance of the color signal processing system and the level balance of the brightness signal processing system to correct errors in color reproducibility and brightness reproducibility of reproduced images caused by differences in color temperature of the light source used. It is an object of the present invention to provide a color video camera with a new configuration that is realized with a simple configuration and can capture a faithful color image of a subject.

[Means for solving problems]

In order to solve the above-mentioned problems, a color video camera according to the present invention includes a color temperature detection means that constantly detects the color temperature of an imaging light source, and an imaging color signal that is a mixture of two or more primary color signal components. a color image sensor that outputs a plurality of images; a color signal processing system that forms each primary color signal from each captured color signal output from the color image sensor; a first level control means for controlling the signal level ratio of each of the primary color signal components based on the above-mentioned color temperature; a luminance signal processing system for forming a luminance signal from each of the imaging color signals; and second level control means for controlling the signal level ratio of the plurality of imaged color signal outputs based on the detection output by the detection means.

[Effect]

In the color video camera according to the present invention, the color temperature of the imaging light source is constantly detected by the color temperature detection means,
A first level control means for controlling the signal level ratio of each primary color signal component of the color signal processing system, and a second level control means for controlling the signal level ratio of each imaged color signal for forming a luminance signal of the luminance signal processing system. The means is automatically operated based on the detection output by the color temperature detection means, and each primary color signal and luminance are detected from a plurality of imaged color signal outputs in a state where two or more primary color signal components obtained by the color image sensor are mixed. form a signal.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color video camera according to the present invention will be described in detail below with reference to the drawings.

The embodiment shown in the block diagram of FIG. 1 is a color image sensor that outputs a plurality of imaged color signals in a state where two or more primary color signal components are mixed, and a complementary color coding filter 1 is disposed in front of the imaging surface.
Equipped with a CCD (Charge Coupled Device) solid-state image sensor 2, three types of imaged color signals _S1 , which are a mixture of two or more primary color signal components color-coded by the complementary color coding filter 1, are provided.
S ₂ , S ₃ For example, white signal Sw, cyan signal Sc,
The yellow signal Sy is output point-by-point from the solid-state image sensor 2.

A point-sequential image color signal S ₁ obtained by capturing an object image with the solid-state image sensor 2,
S ₂ and S ₃ are color separated and converted into simultaneous signals by the color separation circuit 3, and the first and second signals of this color separation circuit 3 are
The signals are supplied from third output terminals 10, 20, and 30 to a color signal processing system for forming each primary color signal Er, Eg, and Eb and a luminance signal processing system for forming a luminance signal Ey.

In this embodiment, the color signal processing system includes three matrix circuits 11, 21, and 31, and has first and second imaging signals supplied from the first and second output terminals 20 of the color separation circuit 3. The red primary color signal Er is sent from the color signals S ₁ and S ₂ to the first matrix circuit 1.
1 and is supplied from the second output terminal 20 of the color separation circuit _3.
A green primary color signal Eg is formed in the second matrix circuit 21, and a second green primary color signal Eg supplied from the second and third output terminals 20 of the color separation circuit 3 is
and the red primary color signal from the third imaging color signals S ₂ and S ₃
Eb is formed by the third matrix circuit 11. Each primary color signal Er obtained by the first to third matrix circuits 11, 21, 31,
Eg and Eb are connected to buffer amplifiers 13 and 2 from the first to third signal synthesis circuits 12, 22, and 32, respectively.
3 and 33, the first to third voltage-controlled variable gain amplifiers 14 for white balance adjustment;
24, 34, and the voltage controlled variable gain amplifiers 14, 24, 34 automatically adjust the white balance as described later. Further, each of the primary color signals Er, Eg, and Eb, which are white-balance adjusted and obtained from each of the voltage-controlled variable gain amplifiers 14, 24, and 34, is
are supplied to the matrix circuit 40 via process circuits 15, 25, and 35, respectively. The matrix circuit 40 receives the primary color signals Er, Eg, Eb.
From there, color difference signals E(B-Y) and E(RY) are formed and supplied to the NTSC encoder 80.

Further, in this embodiment, the luminance signal processing system includes each imaged color signal supplied from the first to third output terminals 10, 20, and 30 of the color separation circuit 3.
S ₁ , S ₂ , and S ₃ are connected to the buffer amplifier 4 from the first to third signal synthesis circuits 42 , 52 , and 62 , respectively.
3, 53, and 63, first to third voltage-controlled variable gain amplifiers 4 for level balance adjustment.
The voltage control type variable gain amplifiers 44, 54, 64 automatically adjust the level balance as described later, and then supply the signals to the signal synthesis circuit 70. .
The signal synthesizing circuit 70 then outputs each of the imaged color signals obtained from the voltage-controlled variable gain amplifiers 44, 54, and 64 and whose level balance has been adjusted.
A brightness signal Ey is formed by adding and combining S ₁ , S ₂ , and S ₃ at a predetermined combination ratio, and this brightness signal
Ey is supplied to the NTSC encoder 80 via the process circuit 75.

The NTSC encoder 80 receives the color difference signals E(B-Y) and E(RY) supplied from the matrix circuit 40 of the color signal processing system and the signal synthesis circuit 70 of the luminance signal processing system. The luminance signal supplied via the process circuit 75
A composite color television signal Sout conforming to the NTSC system is formed from Ey and the composite color television signal Sout is outputted from the signal output terminal 90.

Furthermore, in this embodiment, as color temperature detection means for constantly detecting the color temperature of an imaging light source (not shown), a photo sensor 110 for detecting red light, which is always illuminated with light from the imaging light source scattered by a white filter 100, and a green It is equipped with a photo sensor 120 for light detection and a photo sensor 130 for blue light detection, and each of these photo sensors 110, 120, 1
Each color light detection output signal Er′, Eg′, obtained at 30
Eb' passes through the buffer amplifiers 111, 121, 131 to the first to third channels of the color signal processing system.
The signal is supplied to the signal synthesis circuits 12, 22, and 32 as a reference level signal for white balance adjustment. Furthermore, each of the above photo sensors 1
Each color light detection output signal Er', Eg', Eb' obtained at 10, 120, 130 is sent to a buffer amplifier 111,
121 and 131, a first signal for forming reference level signals Es ₁ ′, Es ₂ ′, Es ₃ ′ for level balance adjustment is provided.
or third matrix circuit 112, 122, 1
32, and each of the above matrix circuits 1
The respective reference level signals Es ₁ ′, Es ₂ ′, and Es ₃ ′ obtained at the terminals 12, 122, and 132 are sent to the first to third signal synthesis circuits 42, 52, and 6 of the luminance signal processing system.
2.

The first to third signal synthesis circuits 12, 22, and 32 of the color signal processing system output the color light detection output signal.
Er', Eg', and Eb' are superimposed on each blanking portion of the primary color signals Er, Eg, and Eb supplied from the first to third matrix circuits 11, 21, and 31, respectively. Further, the first to third signal synthesis circuits 42, 52, and 62 of the luminance signal processing system are configured to output each reference level signal for level balance adjustment.
Es ₁ ′, Es ₂ ′, and Es ₃ ′ are the imaged color signals S ₁ , S ₂ , and S 3 that are supplied from the first to third signal output terminals 10 , 20 , and 30 of the color separation circuit ₃ . It is designed to be superimposed on each blanking part of .

The color signal processing system includes first to third S, which sample and hold (S/H) each output from each voltage-controlled variable gain amplifier 14, 24, 34 at each blanking timing. First to third signal level detection circuits 212, 222, 232 are provided with respective hold outputs from the /H circuits 211, 221, 321, and blanking of each of the primary color signals Er, Eg, Eb is provided. Each of the above color light detection output signals superimposed on the
The signal levels of Er', Eg', and Eb' are detected by the signal level detection circuits 212, 222, and 232, respectively. Further, each signal level of each color light detection output signal Er', Eg', Eb' detected by each signal level detection circuit 212, 222, 232 is determined by a first and a second level comparator 2.
13 and 233, and the level difference between the signal level of the color light detection output signal Eg' by the photo sensor 120 for detecting green light and the signal level of each of the other color light detection output signals Er' and Eb' is detected. be done. And each level comparator 21
3 and 233 to the first and third voltage-controlled variable gain amplifiers 14 and 34 as gain control signals via buffer amplifiers 214 and 234, respectively. Primary color signals formed by color signal processing system
White balance adjustment for Er, Eg, and Eb is automatically performed.

Further, the luminance signal processing system includes first to third circuits that sample and hold (S/H) each output from each voltage-controlled variable gain amplifier 44, 54, 64 at each blanking timing. First to third signal level detection circuits 234, 352, and 362 are provided to which respective hold outputs from the S/H circuits 341, 351, and 361 are supplied, and each of the above-mentioned imaged color signals S ₁ , S ₂ , The signal levels of the reference level signals Es ₁ ′, Es ₂ ′, and Es ₃ ′ superimposed on each blanking portion of S ₃ are detected by the signal level detection circuits 342, 352, and 362. ing. Further, the signal levels of the reference level signals Es ₁ ′, Es ₂ ′, and Es ₃ ′ detected by the signal level detection circuits 342 , 352 , and 362 are transmitted to first and second level comparators 343 , 363, and the reference level signals ES 1 ′ and Es ₃ ′ by the other matrix circuits 112 and 132 are compared with each other at the signal level of the reference level signal Es ₂ ′ given by the second matrix circuit ₁₂₂ . The level difference between the signal levels is detected. And each level comparator 34
By supplying the level difference outputs obtained at 3 and 363 to the first and third voltage-controlled variable gain amplifiers 44 and 64 as gain control signals via buffer amplifiers 344 and 364, respectively. Each imaging color signal output S ₁ , S ₂ , Sm used to form the luminance signal Ey in the luminance signal processing system
The signal level ratio is automatically controlled to adjust the level balance.

In the above-described embodiment, the color signal processing system and the luminance signal processing system are each provided with a level control means using closed-loop feedback control to adjust the white balance of the color signal processing system and the level balance of the luminance signal processing system. I tried to do the adjustment, but
The present invention is not limited to the above-described embodiment, but for example, as in the second embodiment shown in FIG. may be provided to perform white balance adjustment of the color signal processing system and level balance adjustment of the luminance signal processing system.

In the second embodiment shown in the block diagram of FIG. 2, the same components as those in the first embodiment described above are designated by the same reference numerals in the drawings, and detailed explanations thereof will be omitted.

In this embodiment, light from an imaging light source (not shown) is scattered by a white filter 100 and constantly irradiated with a photo sensor 110 for detecting red light, a photo sensor 120 for detecting green light, and a photo sensor 130 for detecting blue light. The respective color light detection output signals Er', Eg', and Eb' are sent to the buffer amplifier 1.
11, 121, 131, the first and second
The signal levels of the above-mentioned color light detection output signals Er', Eg', and Eb' are sent to the level comparators 213 and 233 of
First and second level comparators 113,1
33, and the level difference between the signal level of the color light detection output signal Eg' by the green light detection photo sensor 120 and each signal level of each of the other color light detection output signals Er' and Eb' is detected. and,
Based on the level difference output of each signal level obtained from each level comparator 113, 133,
The digital arithmetic processing circuit 140 forms control data Dr, Db for white balance adjustment of the color signal processing system and control data Dy ₁ , Dy ₃ for level balance adjustment of the luminance signal processing system. Control data Dr and Db for white balance adjustment formed by the digital arithmetic processing circuit 140 are converted into analogs by digital-to-analog (D/A) converters 114 and 134, respectively, and are used as gain control signals for the color signal processing system. The white of the primary color signals Er, Eg, and Eb formed in the color signal processing system by being supplied to the first and third voltage-controlled variable gain amplifiers 14 and 34 Balance adjustment is automatically performed using open-loop control. Similarly, control data Dy ₁ for level balance adjustment formed by the digital arithmetic processing circuit 140,
Dy ₃ is converted into an analog signal by digital-to-analog (D/A) converters 144 and 164, respectively, and used as a gain control signal in the first and third voltage-controlled variable gain amplifiers of the luminance signal processing system. 4
4 and 64, the signal level ratio of each imaged color signal S ₁ , S ₂ , and S ₃ used to form the luminance signal Ey in the luminance signal processing system is automatically adjusted by open-loop control. It is designed to control and adjust the level balance.

In each of the embodiments described above, the color image sensor 2 obtains an imaged color signal output in a state where two or more primary color signal components are mixed, performs signal processing using a so-called separate luminance method, and outputs a standard television signal of the NTSC method. White balance adjustment of the color signal processing system and level balance adjustment of the luminance signal processing system to correct errors in color reproducibility and brightness reproducibility of reproduced images caused by differences in color temperature of the imaging light source in color video cameras. A common photo sensor 110, 120, 13 detects the color temperature change of the imaging light source.
Since the detection is performed automatically at 0, it is possible to realize a color video camera that can capture a faithful color image of a subject with a simple configuration.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, in the color video camera according to the present invention, the color temperature of the imaging light source is constantly detected by the color temperature detection means, and the signal level ratio of each primary color signal component in the color signal processing system is and a second level control means that controls the signal level ratio of each imaged color signal for forming the luminance signal of the luminance signal processing system based on the detection output of the color temperature detection means. to operate automatically,
Each primary color signal and a luminance signal are formed from a plurality of imaging color signal outputs that are a mixture of two or more primary color signal components obtained by a color image sensor, so that reproduction caused by differences in color temperature of the imaging light source is avoided. A function that automatically adjusts the white balance of the color signal processing system and the level balance of the luminance signal processing system to correct errors in image color reproducibility and brightness reproducibility is realized with a simple configuration, and the image of the subject is Faithful color imaging can be performed, and the intended purpose can be fully achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a color video camera according to the present invention, and FIG. 2 is a block diagram showing a first embodiment of a color video camera according to the present invention. 1...Complementary color coding filter, 2...Solid image sensor, 11, 21, 31, 112,
122, 132...matrix circuit, 12, 2
2, 32, 42, 52, 62, 70...signal synthesis circuit, 14, 24, 34, 44, 54, 64...
Voltage controlled variable gain amplifier, 80... NTSC encoder, 110, 120, 130... Photo sensor, 113, 133, 213, 233, 343,
363... Level comparator, 114, 13
4,144,164...Digital analog converter, 140...Digital arithmetic circuit, 212,22
2,232,342,352,362...Level detection circuit.

Claims (1)

[Claims] 1. A color temperature detection means that constantly detects the color temperature of an imaging light source, a color image sensor that outputs a plurality of imaging color signals in a state where two or more primary color signal components are mixed, and each imaging unit output from the color image sensor. a color signal processing system that forms each primary color signal from the color signal; and a first level provided in the color signal processing system that controls the signal level ratio of each of the primary color signal components based on the detection output of the color temperature detection means. a control means, a brightness signal processing system that forms a brightness signal from each of the imaged color signals, and a signal level of the plurality of imaged color signal outputs based on the detection output of the color temperature detection means provided in the brightness signal processing system. a second level control means for controlling the ratio, and forms each primary color signal and a luminance signal from a plurality of imaged color signal outputs in a mixed state of two or more primary color signal components obtained by the color image sensor. A color video camera.