JPS61150489A - Color video camera - Google Patents

Abstract

PURPOSE:To execute faithfully color image pick-up of an object image by adjusting automatically the white balance of the chrominance components processing system to correct the error of color reproducibility and luminance reproducibility of the reproducing picture which occur due to the difference of a color temperature of the light source for image pick-up, and adjusting the level balance of a luminance signal processing system. CONSTITUTION:In a color signal processing system, a red primary color signal Er is formed by a matrix circuit 11 from the first and second image pick-up color signals S1 and S2 supplied from an output terminal 20 of a separating circuit 3, a green primary color signal Eg is formed by a matrix circuit 21 from the second image pick-up color signal S2 and further, a blue primary color signal Eb is formed by the third matrix circuit 31 from the second and the third image pick-up color signals S2 and S3. For respective primary color signals Er, Eg and Eb, the white balance is automatically adjusted by voltage control type variable gain amplifiers 14, 24 and 34 for adjusting the white balance. Further, respective image pick-up color signals S1-S3 are supplied to respective voltage control type variable gain amplifier 44, 54 and 64, and the level balance is adjusted automatically.

Description

[Detailed Description of the Invention] [Field of Industrial Application] 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 an image pickup tube or a solid-state image sensor, and the color coding filter converts imaging light into three primary color components R, G, and H. Color separation is performed to capture color images, and primary color signals and luminance signals are generated from the image capture 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 white balance must be adjusted according to the color temperature of the imaging light source. must be adjusted 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 R5 of the red component of the imaging output, the signal level B of the green component, and the signal level B of the blue component. The ratio of R:G:B=l
This was done by setting the level adjustment circuits provided for each color signal line so that: 1:L. Further, for example, as disclosed in Japanese Patent Publication No. 56-4993, the color temperature of the imaging light source is constantly detected,
A white balance adjustment device has also been proposed that automatically follows the change in color temperature over time.

In addition, conventionally, a complementary color coding filter that separates the imaging light into complementary color components such as yellow Y e + cyan Cy and magenta Mg has been disposed in front of the imaging surface of the image sensor to perform color imaging. A color video camera using complementary color coding has been proposed in which a primary color signal and a luminance signal are formed from the output.

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 in a state where multiple primary color components obtained by the image sensor are mixed. , it is possible to improve imaging sensitivity, S/N, etc.

By the way, as mentioned above, in a color video camera using 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 a plurality of primary color components obtained by an image sensor are mixed. For example, when forming luminance signals and color signals compatible with the NTSC system, differences in the color temperature of the imaging light source will cause errors in the luminance reproducibility of the reproduced image, so when R=
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 the brightness signal is G-B. It is also necessary to perform level balance adjustment for the captured color signals.

[Problem that the invention seeks to solve]

By the way, as mentioned above, in a color video camera using a complementary color coding filter, a color signal is obtained by performing signal processing corresponding to the separation luminance method on the imaged color signal output, which is a mixture of multiple primary color components obtained by an image sensor. When forming a luminance signal and a color signal processing system, 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 were to be automatically controlled, the configuration would become extremely complicated. There was a problem with it being put away.

Therefore, in view of the above-mentioned problems, the present invention obtains an imaged color signal output in a state in which two or more primary color signal components are mixed together from a color image sensor, performs signal processing using a so-called separated luminance method, and converts the signal into a desired method. White balance adjustment and brightness signal processing in the color signal processing system that corrects 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 that output standard television signals. An object of the present invention is to provide a color video camera with a new configuration that realizes a function of automatically adjusting the level balance of the system with a simple configuration and can perform faithful color imaging of a subject image.

[Means for solving problems]

In order to solve the above-mentioned problems, a color video camera according to the present invention includes a color image sensor that outputs a plurality of captured color signals in a state where two or more primary color signal components are mixed, and a color image sensor output from the color image sensor. a color signal processing system that forms each primary color signal from each imaged color signal; a first level control means provided in the color signal processing system that controls the signal level ratio of each of the primary color signal components; and each of the imaged color signals a luminance signal processing system for forming a luminance signal; a second level control means provided in the luminance signal processing system for controlling a signal level ratio of the plurality of imaging color signal outputs; and a control signal for one of the level control means. and control signal forming means for forming a control signal for the other level control means based on the level control means.

[Effect]

The color video camera according to the present invention includes a first level control means for controlling the signal level ratio of each primary color signal component in the color signal processing system, and a signal level of each imaging color signal for forming a luminance signal in the luminance signal processing system. The second level control means for controlling the ratio is automatically operated by the control signal forming means for forming the 'M multiplier signal of the other level control means based on the control signal of one level control means. Each primary color signal and a luminance signal are formed from a plurality of imaged color signal outputs in a state where two or more primary color signal components obtained by the sensor are mixed.

〔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.
A CCD (Charge) is placed in front of the imaging surface.
(Coupled Device) includes a solid-state image sensor 2, and three types of imaged color signals S, which are a mixture of two or more primary color signal components color-coded by the complementary color coding filter 1;

S2. S, for example, white signal S w + cyan signal S
c.

A yellow signal Sy is output point-by-point from the solid-state image sensor 2.

Point-sequential image color signals obtained by capturing an object image with the solid-state image sensor 2 5lls, , S
j are color separated and converted into simultaneous signals by the color separation circuit 3, and the first . Each primary color signal E r + from the second and third output terminals 10, 20.30
Color signal processing system for forming E g + E b and luminance signal E
The signal is supplied to a luminance signal processing system for forming 31.

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. Color signal S, , S.

A red primary color signal Er is formed in the first matrix circuit 11, and a red primary color signal Er is formed in the second output terminal 2 of the color separation circuit 3.
A green primary color signal Eg is formed in the second matrix circuit 21 from the second imaged color signal S7 supplied from 0, and is further connected to the second and third output terminals 20 of the color separation circuit 3.
The second and third imaged color signals SJL+ supplied from
From S3, a red primary color signal Eb is formed in the third matrix circuit 11. Each of the primary color signals E r + E g + and E b obtained by the first to third matrix circuits 11, 21.31 is
to the third signal synthesis circuit 12, 22.32 via the buffer amplifier 13°23.33 to the first to third voltage-controlled variable gain amplifier 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. Furthermore, each of the voltage controlled variable gain amplifiers 14.24.3
The white balance-adjusted primary color signals Er+Eg+Eb obtained from 4 are supplied to the matrix circuit 40 via process circuits 15, 25, and 35, respectively. The matrix circuit 40 receives each of the primary color signals E.
Color difference signal E (B-Y) from r, Eg, Eb,
E (1?~Y) is formed and supplied to the NTSC encoder 80.

Further, in this embodiment, the luminance signal processing system is connected to the first to third output terminals 10.20.3 of the color separation circuit 3.
Each imaged color signal S, supplied from 0.

S, S, are buffer amplifiers 43, 53゜63, respectively.
is supplied to the first to third voltage-controlled variable gain amplifiers 44.54.64 for level balance adjustment, and the voltage-controlled variable gain amplifiers 44.54.64 automatically output the voltage as described below. The signal is level balanced and supplied to the signal synthesis circuit 70. Then, the signal synthesis circuit 70 receives the level-balanced imaged color signals S, SL, S, obtained from the voltage-controlled variable gain amplifiers 44, 54, and 64.
A brightness signal Ey is formed by adding and combining them at a predetermined combination ratio, and this brightness signal EV is sent to the process circuit 75.
The signal is supplied to the NTSC encoder 8° through the NTSC encoder 8°.

The NTSC encoder 80 receives the color difference signal E supplied from the matrix circuit 40 of the color signal processing system.
(B-Y), E (R-Y), and the process circuit 7 from the signal synthesis circuit 70 of the luminance signal processing system.
A composite color television signal 5out conforming to the NTSC system is formed from the luminance signal Ey supplied through the NTSC system, and this composite color television signal 5out is outputted from a 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 photosensor 110 for detecting red light, which is constantly illuminated with light from the imaging light source scattered by a white filter 100; Photosensor 120 for detecting green light and photosensor 1 for detecting blue light
30, each of these photosensors 110, 12
Each color light detection output signal Er" obtained at 0.130,
Eg'.

Eb' is now supplied as a reference level signal for white balance adjustment to the first to third signal synthesis circuits 12, 22, and 32 of the color signal processing system via the buffer amplifiers 111, 121, and 131. ing.

First to third signal synthesis circuits 12 of the color signal processing system
, 22.32 are the respective color light detection output signals Er'+E
g'+Eb' is superimposed on each blanking portion of the primary color signals Er, Eg, and Eb supplied from the first to third matrix circuits It, 21.31.

The color signal processing system is provided with sample and hold (S/H) outputs from the voltage-controlled variable gain amplifiers 14, 24, and 34 at each blanking timing.
) first to third S/H circuits 211, 221, 2
31 to which each hold output is supplied.
signal level detection circuits 212, 222, and 232 are provided, and each color light detection output signal Er' superimposed on each blanking portion of each of the primary color signals Er, Eg, and Eb is provided.
.

The signal levels of Eg' and Eb" are detected by the signal level detection circuits 212, 222, and 232.
It has become ゛. Further, each signal level of each of the color light detection output signals Er', Eg'+Eb' detected by each of the signal level detection circuits 212, 222, 232 is detected by a first and a second level comparator 213.
．． 233, the signal level of the color light detection output signal Eg' from the above-mentioned green light detection photosensor 120 is compared with each other color light detection output signal E r',
A level difference between each signal level of E b' is detected. The level difference outputs obtained from each of the level comparators 213 and 233 are used as gain control signals for the first and third voltage-controlled variable gain amplifiers 14.3, respectively.
4, the white balance adjustment of the primary color signals Er, Eg, and Eb formed by the color signal processing system is automatically performed.

Furthermore, each of the signal level detection circuits 212, 222.2
The above-mentioned color light detection output signal detected at 32 "4 Er'
, Eg'+Eb' each signal level is a reference signal level for level balance adjustment E S+ + E 311
First to third matrix circuits 31 for ESJ formation
o.

320 and 330, and each signal level of each reference signal level Es7° + E5JI E% obtained in each of the matrix circuits 310, 320, 330 is the first
and the respective reference level signals from the other matrix circuits 112 and 132 are compared with each other by the second level comparators 343 and 363, and the signal level of the reference level signal Es provided by the second matrix circuit 122 is compared with the reference level signal Es provided by the second matrix circuit 122. Es;.

A level difference between the signal levels of E 33 is detected. By supplying the level difference outputs obtained by the level comparators 343 and 363 to the first and third voltage-controlled variable gain amplifiers 44 and 64 as gain control signals, respectively, the luminance signal processing system Each imaged color signal S, 1S2 used for forming the luminance signal EV in
．． The signal level ratio of S3 is automatically controlled to adjust the level balance.

In the above-described embodiment, the respective color light detection output signals ErZ Eg for white balance adjustment of the color signal processing system are
Based on the signal levels of ', Eb', level balance adjustment reference signals Es, ``+E sl+E s
, + is used to adjust the level balance of the luminance signal processing system. However, the present invention is not limited to the above-described embodiments, and can be applied to, for example, color coding of a color image sensor. Each corresponding complementary color component is detected by a photosensor for detecting color temperature change of the imaging light source, and the level balance of the luminance signal processing system is adjusted based on the detection output, and the white balance is adjusted based on the detection output. The white balance adjustment control of the color signal processing system may be automatically performed by forming a level control signal for the color signal processing system. The level control signal used for white balance adjustment and level balance adjustment of the luminance signal processing system may be formed by digital processing.

In the second embodiment shown in the block diagram of FIG.
Components that are the same as those in the first embodiment described above are designated by the same numbers in the drawings, and detailed description thereof will be omitted.

The color video camera of this embodiment uses a color image sensor to capture a white subject when adjusting white balance, thereby omitting the photo sensor for detecting changes in color temperature of the imaging light source. , each matrix circuit 1 from each imaged color signal S, , S, sj obtained by photographing a white object with a solid-state image sensor 2 provided with a complementary color coding filter I.
1, 21. Primary color signals E r, E g+ formed at 31
Each output of each voltage-controlled variable gain amplifier 14, 24, and 34 of the color signal processing system that performs white balance adjustment on Eb is connected to the first to third gate circuits 210, 220, 230.
via the first to third signal level detection circuits 212,
222.232.

Each of the above signal level detection times 1i11212, 222.23
Each of the above primary color signals E r+ E g+ detected at 2
E b Each signal level is increased by bumper @8214
224.234 to the first and second level comparators 215.235, and the green primary color signal
and the signal levels of the other red and blue primary color signals qEr and Eb are compared by the respective level comparators 215 and 235. In addition, each level comparator 213
, 233 are outputted from the up/down counter 216,
235 as a count pulse, and the green primary color signal Eg is supplied to each of the up/down counters 216 and 235 as a count pulse.
Ike's red and blue primary color signals for the signal level Er +
The level difference between the signal levels of E b is calculated digitally. And each of the above up/down counters 216.2
Control data Dr and Db for white balance adjustment which digitally indicate the level difference between the signal level of the green primary color signal Eg obtained in step 35 and the signal level of the other red and blue primary color signals Er and Eb are respectively digital analog ( D
/A) The first and third ``voltage controlled variable gain amplifiers 14, 34 of the chrominance signal processing system are converted into analog signals by the converters 217 and 237 and converted into analog gain control signals.
The white balance adjustment of the primary color signals E r+E g+E b formed by the color signal processing system is automatically performed.

In addition, data Dr and Db digitally indicate the level difference between the signal level of the green primary color signal Eg obtained by each of the amplifier down counters 216 and 235 and the signal level of other red and blue primary color signals %Er and Eb. Level balance adjustment control data D 31. + DYs is supplied to each digital arithmetic processing circuit 346 and 366 for forming Ys. Each of the digital arithmetic processing circuits 346.
Control data Dy, Dy7 for level balance adjustment formed in 366 are digital analog (D
/A) The converter 347, 367 converts the signal into an analog gain control signal, and outputs the luminance signal as a gain control signal to the first and third voltage-controlled variable gain amplifiers 44.
64, each imaged color signal S is used to form the luminance signal Ey in the luminance signal processing system.
1. The signal level ratio of SL and SJ is automatically controlled by open loop control to 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 in which 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. In a color video camera, a control signal for a level control means for level balance adjustment in a luminance signal processing system is formed based on a control signal for a level control means for white balance adjustment in a color signal processing system, and a control signal for a level control means for adjusting a level balance in a luminance signal processing system is generated. The white balance adjustment of the color signal processing system and the level balance adjustment of the luminance signal processing system, which correct errors in the color reproducibility and luminance reproducibility of reproduced images caused by differences in color temperature, are automatically performed. With this configuration, it is possible to realize a color video camera that can capture a faithful color image of a subject.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, the color video camera according to the present invention includes a level control means for controlling the signal level ratio of each primary color signal component in the color signal processing system, and a luminance signal forming means in the luminance signal processing system. and a level control means for controlling the signal level ratio of each of the image color signals of tii to be automatically operated by a control signal forming means for forming a control signal for the other level control means based on a control signal for one level control means. , each primary color signal and a luminance signal are formed from a plurality of imaged color signal outputs that are a mixture of two or more primary color signal components obtained by a color image sensor, so that reproduced images caused by differences in color temperature of the imaging light source are A simple configuration realizes functions that automatically adjust the white balance of the color signal processing system and the level balance of the luminance signal processing system to correct errors in color reproducibility and brightness reproducibility. Color imaging can be performed, and the intended purpose can be fully achieved.

[Brief explanation of drawings]

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-state image sensor 11.21.31... Matrix circuit 14.24, 3
4, 44, 54.64...Voltage controlled variable gain amplification note 70...Signal synthesis circuit 80...NTSC encoder 212.222.232...Level detection circuit 213.
233, 215, 235, 343° 363... Level comparator 216.236... Up/down count 217.2
37,347,367...Digital analog converter

Claims (1)

[Claims] 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; a color signal processing system that forms each primary color signal from each imaged color signal output from the color image sensor; a first level control means provided in the signal processing system for controlling the signal level ratio of the respective primary color signal components; a luminance signal processing system for forming a luminance signal from each of the imaging color signals; and a first level control means provided in the luminance signal processing system. a second level control means for controlling a signal level ratio of the plurality of imaged color signal outputs; and a control signal forming means for forming a control signal for the other level control means based on a control signal for one level control means. A color video camera comprising: a color video camera configured to form 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.