JPH0473356B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a color temperature compensation device for a color television camera, which detects the color temperature of a shooting screen or a plurality of areas around the shooting screen, and performs color temperature compensation according to color temperature information of each area. The present invention relates to a color temperature compensation device for a color television camera. Prior Art (Figs. 1 to 6) Fig. 1 is a block diagram of a color temperature compensation circuit of a conventional color television camera, Fig. 2 is a configuration diagram of a color filter, and Fig. 3 is a diagram of another conventional color television camera. A block diagram of the color temperature compensation circuit of a digital camera. Figure 4 is a spectral characteristic diagram depending on color temperature. Figure 5 is a spectral characteristic diagram of red and blue signals depending on color temperature. Figure 6 is a gain correction of red and blue signals depending on color temperature. A diagram showing the amount is shown. If the color temperature of the light illuminating the subject changes, the color temperature of the color television camera will change, and even if a white subject is photographed, it will not be photographed as white. Therefore, adjust the color temperature of the color television camera to be higher or lower. , it is necessary to perform color temperature compensation and white balance. A conventional general configuration of this type of color temperature compensation circuit is shown in FIG. In the figure, a striped color filter 1 is arranged in front of an image pickup tube 2. As shown in FIG.
Cross the W filter and Y _E -W filter,
The Cy-W filter has the same phase for each horizontal scan, and Y _E
-W filters are arranged so that the phase is inverted every horizontal scan. The output of the image pickup tube 2 is amplified by a preamplifier 3 and applied to low-pass filters 4 and 5 that separate the luminance signals Y _H and Y _L and a bandpass filter 6 that separates the color modulation signal. A red signal R modulated by the Cy-W filter for each horizontal scan and a blue signal inverted for each horizontal scan by the Y _E -W filter are delayed by a delay line 7 for one horizontal period. The output signal from the bandpass filter 6 and the output signal from the one horizontal period delay line 7 are added to an adder 8 and a subtracter 9, respectively, and a red signal R and a green signal B are output from the adder 8 and the subtracter 9, respectively. . These output signals are sent to detectors 10 and 1.
1 and outputs a low-frequency red signal R and a blue signal B. Next, in order to match the gains of the red signal R and the blue signal B according to the color temperature information obtained based on the low frequency signal for color signals, the gains are adjusted by variable gain amplifiers 12 and 13, and the color difference signal R is output from subtractors 14 and 15. _-YL ,B
−Y _L is obtained and sent to the encoder 16 along with the luminance signal Y _H.
plus a standard television signal. The automatic color temperature compensation circuit in this color television camera is comprised of blocks 17-22. Before pointing a color television camera at the subject and photographing it, a white subject is photographed, and the color difference signals R- _YL and B- _YL output at this time are adjusted so that they become zero. That is, the comparison circuits 17 and 18 use the reference signal set so that the color difference signals R-Y _L and B-Y _L become zero, and the output color difference signals R-Y _L , B
−Y _L is compared. Switches 19 and 20 are closed while photographing a white object, and the signals obtained at this time are held in hold circuits 21 and 22. This held signal is transferred to variable gain amplifier 1.
In addition to external voltage control terminals 2 and 13, the gain is controlled. When switches 19 and 20 are closed, a closed loop is formed by variable gain amplifiers 12 and 13, subtracters 14 and 15, comparison circuits 17 and 18, switches 19 and 20, and hold circuits 21 and 22, and the color difference signal is It acts so that R−Y _L and B−Y _L become zero. When the color difference signal becomes zero, switches 19 and 20 are opened, and hold circuits 21 and 22 hold the voltage so that the color temperature does not change. This color television camera has the disadvantage that it cannot be used continuously because it is necessary to reset (redetect) color temperature information each time the color temperature of illuminating the subject changes. A color television camera that eliminates the above-mentioned drawbacks and is equipped with a color temperature compensator that automatically adjusts the color temperature at all times has been known. The outline will be explained based on FIG. 3. The blocks designated with reference numerals 1 to 16 shown in the figure are the same as the blocks shown in FIG. 1, and therefore their explanation will be omitted. 31 and 32 are color detectors that detect different colors emitted by a light source, and 33 is a color temperature detector that obtains color temperature information from the ratio of two different color signals detected by the color detectors. Color temperature compensators 34 and 35 generate gain control voltages for the variable gain amplifiers 12 and 13 for red and blue signals using the signals output from the color temperature detector 33. As seen in the spectral characteristic diagram based on color temperature shown in FIG. 4, the color temperature of illumination changes at each wavelength. Therefore, the values of the red and blue signals applied to the detectors 10 and 11 change depending on the color temperature.
The reason is that, as shown in FIG. 5, the spectral characteristics of the red signal and the green signal change. The color temperature detector 33 detects the color temperature represented by the ratio of the values of two colors by utilizing the property that the spectral characteristics change when the color temperature changes. Therefore, when the output ratio of the variable gain amplifiers 12 and 13 changes from 3200 to 6000 as shown in FIG. 5, it becomes about 1/2 for a red signal and about 2 times for a green signal. here,
The gains of the variable gain amplifiers 12 and 13 at the time of 4500〓 must be approximately 0.75 times for the red signal variable gain amplifier 12 and 1.5 times for the blue signal variable gain amplifier 13 in order to make the color difference signal zero. Next 6000〓
In order to make the color difference signal zero in this case, the variable gain amplifier 12 for the red signal must be set to 1.5 times, and the variable gain amplifier 13 for the blue signal must be set to 0.75 times. Therefore,
As shown in FIG. 6, the gains of the variable gain amplifiers 12 and 13 for red and blue signals must be changed depending on the color temperature. Color temperature compensators 34 and 35 generate control voltages for changing this gain. The color temperature compensators 34 and 35 compensate for color temperature by applying a control voltage that changes the gain to the red signal variable gain amplifier 12 and the blue signal variable gain amplifier 13. In color television cameras equipped with this conventional color temperature compensation device, in order to perform proper color temperature compensation, light with the same color temperature as the light illuminating the subject must be incident on the color detector. Under conditions that violate this assumption, it becomes difficult to perform appropriate color temperature compensation. For example, if the subject is a person bathed in the light of the setting sun, the photographer turns his back to the setting sun, but the light that enters the color detector is still mostly unfaded light from the blue sky. Since the color detector detects the color temperature of the blue sky when It acts to lower the gain of the gain amplifier and increase the gain of the red signal variable gain amplifier. Therefore, the blue video signal becomes weak and the red video signal is made strong for color temperature compensation, so that the person being photographed appears abnormally reddish on a display device or the like. Furthermore, when photographing the outdoors from indoors, there is a high possibility that light from inside the room will enter the color detector of the color television camera, rather than light from the object outdoors. Therefore, the color temperature detector outputs the color temperature of the indoor light, and does not compensate for the color temperature for the outdoor subject, but compensates for the indoor light, so the subject may appear unnatural. There is a drawback that the image is displayed on a display device, etc. in a color-tinged state. The reason for this is that with the conventional external sensor method, in which the color detector is placed in a housing other than the camera's lens system, the light detection area is at the base angle, so light with the same color temperature as the reflected light from the subject is colored. This is because the light is not incident on the detector, making it impossible to perform proper color temperature compensation. Purpose of the Invention The present invention solves the drawbacks of conventional color temperature compensation devices for color television cameras, and is designed to detect the color temperature of incident light from a shooting screen or a plurality of areas around the shooting screen. A further object of the present invention is to provide a color temperature compensation device for a color television camera that can perform more appropriate color temperature compensation. Structure of the Invention A color temperature compensation device for a color television camera according to the present invention includes an imaging means for converting subject light through an imaging lens into a color image signal, and a gain of at least two or more color signals in the color image signal. a plurality of color temperature detection means for respectively detecting the color temperature of incident light from a photographing screen by the imaging means or a plurality of areas around the photographing screen; illuminance detection means for detecting illuminance information corresponding to the illuminance of at least a portion of the screen; and outputs of the plurality of color temperature detection means to be weighted and combined to perform color temperature compensation of the color signal, and to perform color temperature compensation according to the color temperature. The color temperature compensation means generates a control signal and supplies it to the gain control means, and the weighting of the plurality of color temperature detection means is changed according to the illuminance information. . The color temperature compensation device for a color television camera of the present invention can be applied to a three-tube (plate) type, a two-tube (plate) type, and a single-tube (plate) type color television camera, and the color temperature The number of pairs of color detectors for detecting color detectors can be increased or decreased as necessary, and the implementation thereof can be changed as appropriate within the scope of the above-described claims. DESCRIPTION OF EMBODIMENTS Embodiments of the color temperature compensation device for a color television camera according to the present invention will be described in detail below with reference to FIGS. 7a-e, 8a-h, and 9a-g. . First, with reference to FIGS. 7a to 7e, the basic concept of the color temperature detection method used in the embodiment of the present invention will be explained. In Fig. 7a, 51 is the subject flower, 5
Reference numeral 2 represents an imaging surface of the image pickup tube, 36 represents a photographing lens, and 31 and 32 represent color detectors. These color detectors 31 and 32
The detectors detect light with wavelengths corresponding to blue and red, respectively, but may also detect light with other wavelengths. FIG. 7b is a perspective view including the subject 51, the photographing lens 36, the vicinity of the subject 1, and the background.
This is shown in Figure c, where 37 is an image frame (photographing screen) of the image pickup tube. The color detectors 31 and 32 are arranged on the periphery behind and below the photographing lens 36. Because of this arrangement, unlike the conventional external sensor method in which a color detector is placed in a housing other than the camera lens system, the light incident through the photographic lens 36 is reflected from the subject itself. Since it is light, the color detectors 31 and 32 can not only detect the color temperature of the reflected light from the subject itself, but also because the color detectors 31 and 32 are arranged around the back of the photographic lens 36, they can detect the light. The area has been expanded, and the color temperature of the light surrounding the subject can also be detected. The photodetection areas are the shaded area 38 in FIG. 7a and the area 38 shown in FIG. 7c. When performing color temperature compensation using such color detectors 31 and 32, it can be configured as shown in FIG. 7d, for example. That is, the reflected light of the object and its surrounding light detected by the color detectors 31 and 32 are converted into electrical signals, which are applied to the color temperature detector 33 to output a color temperature signal. This color temperature output signal is applied to color temperature compensators 34 and 35, and then added to the variable gain amplifier 12 for the red signal and the variable gain amplifier 13 for the blue signal to adjust the gain and perform appropriate color temperature compensation. FIG. 7e shows an example in which the above-described color detector is applied to a zoom lens system. In FIG. 7e, 39 is a focusing lens, 40 is a variator lens, 41 is a compensator lens, 42 is a focal lens, and 43 is a relay lens, and these lenses constitute a zoom lens system. Focusing lens 39
has a focus adjustment function to adjust the focal length, a variator lens 40 has a function to change the focal length, a compensator lens 41 has a function to correct the movement of the image point caused by changing the magnification, and a focal lens 42 has a relay lens 43. The relay lens 43 has a function of focusing the final image that comes through the lens system on the imaging plane of the image pickup tube 2 with a predetermined size and brightness. 2 is an image pickup tube. Further, reference numerals 31 and 32 indicate color detectors, which are arranged between the focusing lens 39 and the variator lens 40 and on the rear periphery of the focusing lens 39. In such an arrangement, the focusing lens 39, which has a focus adjustment function, moves only slightly when focusing, so even if the angle of view seen from the imaging plane changes due to zooming, The light detection areas of the color detectors 31 and 32 viewed through the focusing lens 39 do not change. Therefore, even in a zoom lens system, color detectors 31 and 32 are installed behind and around the photographic lens.
By placing the focusing lens 3
It is possible to detect the reflected light from the subject through the lens 9 and its surrounding light. As for the circuit device for performing color temperature compensation using the signals detected by the color detectors 31 and 32, it is sufficient to use exactly the same circuit device as shown in FIG. 7d, so a description thereof will be omitted. Next, a method for detecting color temperatures in a plurality of regions using such a color detector will be described below with reference to FIGS. 8a to 8h. In FIGS. 8a and 8b, 51 is a flower as a subject, 52 is an imaging tube, 36 is a photographic lens, 31
a and 32a, 31b and 32b, 31c and 32c,
31d and 32d are four pairs of color detectors, which are arranged behind the photographic lens 36 and at different angles of 90 degrees around the photographic lens 36 on the top, bottom, left and right, as shown in the figure. In FIG. 8C, 37 indicates the image frame of the imaging plane of the image pickup tube 2, and the color detectors 31a and 32a, 31b and 32b, 31
The photodetection areas of c and 32c, 31d and 32d are lower area D (44a), upper area U (44b), and left area L.
(44c) and the right region R (44d). These four light detection areas cover the subject and its entire surroundings. Therefore, the subject and its surrounding light in the light detection area covering the subject and its surroundings are detected by the four pairs of color detectors described above, and the output signals are shown in FIG. 8e, which will be described later.
is input to an evaluation calculation circuit 45 shown in FIG. In Fig. 8d, for example, the zoom lens system has four
An example in which a pair of color detectors are arranged will be described. Focusing lens 39, variator lens 4
0. The functions of the compensator lens 41, focal lens 42, and relay lens 43 have been explained in FIG. 7e, so their explanation will be omitted.
Behind the focusing lens 39, four pairs of color detectors 31a and 32 are installed around the focusing lens 39 on the upper, lower, left and right sides at different angles of 90 degrees.
a, 31b and 32b, 31c and 32c, and 31d and 32d are arranged. Next, an example of evaluation and judgment when performing color temperature compensation using these four pairs of color detectors is shown in Fig. 8e~
This will be explained using h. In FIG. 8e, four pairs of color detectors 31a and 3
2a, 31b and 32b, 31c and 32c, 31d
The output signal of 49 into an analog quantity and output to color temperature compensators 34 and 35. This output signal is applied to the red signal variable gain amplifier 12 and the blue signal variable signal gain amplifier 13 in FIG. 7d to effect proper color temperature compensation. In FIG. 8f to FIG. 8h, the lower region D,
A flowchart of evaluation determination in which color temperature values Dc, Uc, Lc, and Rc in the upper region U, left region L, and right region R are detected by four pairs of color detectors to obtain a color temperature compensation signal will be described. In this evaluation judgment flowchart, if the power is on as shown in the figure, color temperature signals Dc, Uc, Lc, and Rc from four pairs of color detectors are input, and among these color temperature detection signals, Comparisons between the two are performed one after another, and the output signal X of the comparison results (a total of 12 comparison results are obtained) is applied to the color temperature compensator. The principle of evaluation judgment for obtaining this output signal X is as follows:
The color temperature signal from a pair of color detectors is determined according to the principle of majority voting, and if the color temperature outputs of the four pairs of color detectors are all different, the output signal Since there is a high possibility that the light in the upper region U is achromatic, the signal applied to the color temperature compensator is set to the color temperature value Uc of the upper region U. Referring again to FIG. 8f to FIG. 8h, the color temperature output signals Uc, Dc, Lc,
Input Rc, first compare whether Uc and Dc are approximately equal or not, and if YES, then compare whether Uc and Lc are approximately equal or not, and if YES, Uc and
Compare whether Rc is approximately equal or not, and if YES (that is, UcDcLcRc), output signal
is set as X=(Uc+Dc+Lc+Rc)/4. Uc and
If the comparison result of Lc is NO, then compare whether Uc and Rc are almost equal or not, and if YES (i.e., UcDc, Uc/Lc, UcRc), the output signal X is X = (Uc + Dc + Rc) /3, but Uc and Rc
If the comparison result of is NO (i.e., UcDc,
Uc/Lc, Uc/Rc), the output signal X is
Dc)/2. Also, the comparison result of Uc and Rc is
If NO (i.e., UcDc, UcLc,
Uc/Rc), output signal X is X=(Uc+Dc+Lc)/
3. Compare whether Uc and Dc are almost equal or not
If (that is, Uc/Dc), compare whether Uc and Lc are approximately equal or not, and if YES, then compare whether Uc and Rc are approximately equal or not.
If YES (i.e., Uc/Dc, UcLc,
LcRc), the output signal X is X = (Uc + Lc + Rc) /
3. If the comparison result of Uc and Rc is NO (i.e., Uc/Dc, Uc/Lc), then a comparison is made to see if Uc and Rc are approximately equal, and if YES (i.e., Uc/Dc, Uc/Lc). Dc, Uc/Lc, UcRc), and the output signal X is X=(Uc+Rc)/2. If the comparison result of Uc and Rc is NO (i.e., Uc/Dc,
UcLc, Uc/Rc), the output signal X is
Lc)/2. Next, compare whether Dc and Lc are approximately equal.
If YES (i.e., Uc/Dc, Uc/Lc,
Uc/Rc, DcLc), then compare whether Dc and Rc are approximately equal or not, and if YES (i.e.,
Uc／Dc、Uc／Lc、Uc／Rc、DcLc、Dc
Rc), and the output signal X is X=(Dc+Lc+Rc)/3. Compare whether Dc and Lc are almost equal or not. YES
If (i.e., Uc/Dc, Uc/Lc, Uc/
Rc, DcLc), then compare whether Dc and Rc are approximately equal or not, and if YES (i.e., Uc/Dc,
Uc/Lc, Uc/Rc, Dc/Lc, DcRc), and the output signal X is X=(Dc+Rc)/2. If the comparison result of Dc and Rc is NO (i.e., Uc/Dc, Uc
/Lc, Uc/Rc, DcLc, Dc/Rc), and the output signal X is X=(Dc+Lc)/2. Compare whether Lc and Rc are approximately equal or not, and if YES (i.e., Uc/Dc, Uc/Lc, Uc/
Rc, Dc/Lc, Dc/Rc, LcRc), output signal
is set as X=(Lc+Rc)/2. If the comparison result of Lc and Rc is NO (i.e., Uc/Dc,
Uc/Lc, Uc/Rc, Dc/Lc, Dc/Rc, Lc/
Rc), and output signal X is assumed to be X=Uc. In the evaluation judgment example described above, the color temperature of the incident light from the shooting screen or the periphery of the shooting screen can be detected without being affected by the presence of a highly saturated subject, and it is possible to perform appropriate color temperature compensation. can. Next, an embodiment of the present invention will be described with reference to FIGS. 9a to 9g. In FIG. 9a, behind the focusing lens 39 of the zoom lens system, four pairs of color detectors 31a and 32a, 31b and 32b, 31c and 32 are arranged around the lens 39 at different angles of 90 degrees.
Place c, 31d and 32d. Furthermore, a pair of color detectors 36a and 36b are provided in the housing of the color television camera other than the lens system, and this is used as an external detector for detecting the color temperature of light other than the light incident through the lens system. use Color temperature information and illuminance information can be obtained from the outputs of the four pairs of color detectors described above, and this will be explained with reference to FIG. 9b. The signals detected by the pair of color detectors 31a and 32a are as follows. are input to an addition circuit 61 and a division circuit 62, respectively, and in the addition circuit 61, the color detector 31
The detection signals from a and 32a are added to obtain illuminance information, and in the division circuit 62, the color detector 3
Color temperature information can be obtained from the ratio of detection signals from 1a and 32a. In addition, the external detector 36
As for a and 36b, only color temperature information is obtained without illuminance information, so signal processing is performed to obtain four sets of illuminance information and four sets of color temperature information from the outputs of the four pairs of color detectors described above. conduct. Referring again to FIG. 9a, the focusing lens 39 adjusts the focus on a subject that is located near infinity, but when the focusing lens 39 is focused, the focusing distance information is the distance. The information is generated from an information generator 58. When photographing at the wide side (short focal length) or the telephoto side (long focal length), focal length information is generated from the focal length information generator 59 by adjusting the variator lens 40 and the compensator lens 41. The output signals from the four pairs of color detectors and the external detector, the focusing distance information from the distance information generator 58, and the focal length information from the focal length information generator 59 are determined by the evaluation judgment circuit 45. is input. Furthermore, in color television cameras,
Strobe mode information when shooting in strobe mode S, manual mode information when shooting in manual mode M by setting the color temperature setting knob on the color television camera housing, and color television camera. The evaluation determination circuit 45 receives information as to whether the image is to be photographed in the strobe mode S, the manual mode M, or the composite mode C, which will be explained later. A block diagram of the evaluation judgment circuit 45 to which the various information described above is input is shown in FIG. 9C. In the figure, R and B are red and blue filters, 31b and 32b are color detectors that detect the color temperature of light in the upper area U of the object, and 31d and 32d are the right area of the object. 31c and 32c are color detectors that detect the color temperature of light in the left region L of the field; 31a and 32a are color detectors that detect the color temperature of the light in the lower region D of the field; This is a color detector that detects the color temperature of. Reference numerals 36a and 36b are provided on the housing of the color television camera other than the lens system, and there is an output of an external detector for detecting the color temperature of light other than the light incident through the lens system, and a The outputs from the four pairs of color detectors are sent to the preamplifier PA
The signal is input to the switching circuit 71 via the switching circuit 71. Furthermore, focusing distance information from the distance signal generator 58;
focal length information from the focal length signal generator 59;
Strobe mode information, manual mode information, and mode selection information M/S/C are input to switching circuit 71. Switching circuit 71
The above-mentioned information sequentially detected by is converted into a digital quantity via an AD converter 72, and
3, performs a judgment evaluation to be described later, converts the obtained signal into an analog quantity by the DA converter 74, and outputs it as a color temperature compensation signal. FIG. 9d shows an arithmetic circuit 73 into which the various information described above is input. The information input to the arithmetic circuit 73 will be explained below. X ₁ is the output value of the external detector G, X ₂ is the output value of the color detector in the upper area U, X ₃ is the output value of the color detector in the left area L, and X ₄ is the output value of the color detector in the left area L. X ₅ is the output value of the color detector in the lower area D.
A is the focusing distance information generated from the distance information generator 58, the output value of which is indicated by l, and is set to 0 when the subject is located close to the subject, and 1 when the subject is located at infinity. , the distance value to the subject is expressed by compressing it into a value between 0 and 1. F
is the focal length information generated from the focal length information generator 59, and its output value is indicated by f. By setting it to 0 for wide and 1 for tele, the value of the focal length between them can be changed from 0 to It is expressed compressed to a value up to 1. B is illuminance information obtained by adding the outputs from four pairs of color detectors, where the illuminance value of the upper area U is L _U , the illuminance value of the left area L is L _L ,
The illuminance value of R in the right region is indicated by L _R , and the illuminance value of the lower region D is indicated by L _D . Manual mode M and strobe mode S are switched to either composite mode C and the input M/S/C mode information is indicated by W, and in the case of manual mode M, W = 00, and in the case of strobe mode S. In case of composite mode C, W=10. K is the color temperature information set by manually selecting the color temperature setting dial provided on the housing of the color television camera.
The value is denoted by K. FIG. 9e is a flowchart showing a specific example of the operation of inputting the various information described above to obtain a color temperature compensation signal. In the figure, when the power is on, the various pieces of information described above are sequentially read through switches in the arithmetic circuit. Loaded M/S/C mode information W
It is determined whether or not W=00, that is, manual mode M. If YES, manual mode M calculation described later is performed. Next, it is determined whether W is W=01, that is, strobe mode S,
If YES, the strobe mode S calculation described later is performed. If the determination of W=01 is NO, W is naturally W=10, which is the composite mode C, and therefore, the computation of the composite mode C, which will be described later, is performed. The arithmetic circuit shown in FIG. 9d is configured to calculate the following arithmetic expression. The arithmetic expression is X=XX. Determining the color temperature compensation signal in each mode using this equation by the arithmetic circuit will be described below. In addition, X indicates a color temperature compensation signal, indicates a value statistically considering the output of external detector G and four pairs of color detectors, and indicates a coefficient vector for manual mode and a focusing distance information vector. , represents the vector product of the focal length information vector, the strobe mode coefficient vector, and the illuminance information vector, and represents the instantaneous values of the external detector G and the four pairs of color detectors as vector quantities. Note that vector quantities are displayed by adding a - sign above the characters. Now, the above is = (1-g ₁ , 1-g ₂ , 1-g ₃ , 1-g ₄ , 1-
_g5 ). however, It is. is expressed as =x ₁ x ₂ x ₃ x ₄ x ₅ or =××××. The color temperature compensation signal X in this embodiment is expressed as a linear combination: X=h ₁ x ₁ + h ₂ x ₂ + h ₃ x ₃ + h ₄ x ₄ + h ₅ x ₅ (1). Note that h ₁ to _{h 5} are coefficients. By changing the coefficients h ₁ to _{h 5} according to various parameters, X is finally determined. Therefore, when formula (1) is expressed as a matrix calculation formula, it becomes: X=[ _{h 1} , _{h 2} , h _{3 , h 4 , h 5 ]} Here, if we set = [h ₁ , h ₂ , h ₃ , h ₄ , h ₅ ] = x ₁ x ₂ x ₃ x ₄ x ₅ , it can be expressed as X = × (3). Now, an external detector G and four pairs of color detectors U,
Since the output values of L, R, D, focusing distance information vector A, focal length information vector, illuminance information vector B, etc. are mutually independent, the coefficient matrix is calculated from the calculation of =×××. You can ask for it. Here, , , are vectors for coefficients formed according to the output of each color detector, subject distance, focal length, and illuminance, respectively. Furthermore, the coefficient vector for strobe mode and the coefficient vector for manual mode are also vector-multiplied. Therefore, =××××× (4). In equation (4), if we set =××××, it can be expressed as X=×× (5). Now, Then, g _i ′ represents the degree of abnormality of the output xi of the color detector. In other words, (xi-xj/xi-xj) ² falls within the range of 0 to 1, and the larger the level difference between the output value xi of the color detector and the output value of other color detectors, the closer it approaches 1. ,
If there is no level difference between the two, it will be 0. Therefore, (xi − xj / xi + xj) ² is calculated for all values of the output value xj of the color detector other than the output value xi of the color detector, and the value g _i ′ obtained by adding these is calculated from 0 to ( It represents the degree of abnormality of the output value xi of the color detector between N-1). Afterwards, indicates the degree of abnormality of the output value xi of the color detector within the range of 0 to 1. Therefore, the vectors mentioned above are = (1-g ₁ , 1-g ₂ , 1-g ₃ , 1-g ₄ , 1-
g ₅ ), the coefficient of the output value xi of the highly abnormal color detector approaches 0, and conversely, the output value x ₁ of the external detector G and the four pairs of color detectors When x ₅ are equal, the vector becomes = [1, 1, 1, 1, 1]. In this way, the vector is connected to the external detector G and 4
This is a vector for comparing the output value level of a paired color detector and reducing the weight of the output value level of an abnormal detector based on the principle of majority voting. Next, depending on the value of the distance information to the subject, let =1-l 0 0 0 0 0 1-l 0 0 0 0 0 l 0 0 0 0 0 l 0 0 0 0 0 α (in addition, α may be any appropriate value in the range of 0<α<1), and when the subject is located at a close distance, l=0 as mentioned above,
Substituting this, we get =1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 α, and if the distance to the subject is infinite, l = 1. Therefore, by substituting this, we get =0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 α. This means that the closer the distance to the subject, the greater the weight of the output from the external detector G and the color detector in the upper area U, and the closer the distance to the subject, the greater the weight of the output from the color detector in the upper area U. This means that the weights of the output values of the color detectors in the region L and right region R become larger. is a vector for performing weighting according to the distance to the subject in this way. Next, depending on the value f where the output value of the focal length information changes from the wide side to the telephoto side, =1-f 0 0 0 0 0 0 0 0 1 0 0 0 0 f 0 0 0 0 f 0 0 0 0 f As mentioned above, when it is on the wide side, f=0, so if we substitute this, =1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, and since f=1 when on the tele side, substituting this gives =0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1. This means that the closer the focal length information vector is to the wide-angle side, the more important the external detector G and the output of the color detector in the upper area U are. The output of G approaches 0, and the left region L, right region R, and upper region U
This means that the weights of the four pairs of color detector outputs, ie, lower region D, are equalized and averaged. In this way, the focal length information vector is a vector for weighting according to the focal length. Next, from the output values Lu, L _L , L _R , L _D of the illuminance information B, the formula indicating the brightness ratio of the upper area U is μ = 3Lu / L _L + L _R + L _D , and using this μ,

[Formula] When the illuminance value Lu of the upper area U increases, the output values of the external detector G and the color detectors of the left area L and right area R are emphasized, and the illuminance value Lu becomes intermediate. In the case of level, emphasis is placed on the output values of the color detectors in the left region L and right region R, and when the illuminance value Lu becomes small, the color detection in the upper region U, left region L, right region R, and lower region D is performed. Weighting is performed to emphasize the output value of the device. The illuminance information vector is a vector for weighting according to the illuminance from the object scene. Next, the calculation process for obtaining the color temperature compensation signal X in manual mode M, strobe mode S, and composite mode C will be explained. Regarding the calculation in manual mode M, let k be the setting value of the color temperature setting dial provided on the casing of the color television camera. The formula for calculating the color temperature compensation signal is given by formula (3).
It is indicated by X=XX. Here, =
Since it is represented by ××××, when substituted into the above equation (3), it becomes X=××××××. Since the color temperature value set manually is k, forming a diagonal matrix of manual mode vectors = k 0 0 0 0 0 k 0 0 0 0 0 k 0 0 0 0 0 k 0 0 0 It becomes 0 0 k. Next, form the vectors as follows: a = [1, 1, 1, 1, 1], = 1 1 1 1 1 . Next, create a matrix of focusing distance information vector A, focal length information vector, strobe mode vector, and illuminance information vector ====1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 is formed, , , , , , matrix multiplication is performed to obtain X=k, and this is output as a color temperature compensation signal. Regarding the calculation of strobe mode S, as in the case of manual mode M, X=×
Vector multiplication of M××××× is performed, and when a diagonal matrix of vectors for strobe mode is formed using the value C set in strobe mode, =C 0 0 0 0 0 C 0 0 0 0 0 C 0 0 0 0 0 C 0 0 0 0 0 C . Next, form the vectors as follows: =[1,1,1,1,1], =1 1 1 1 1 . Matrix of focusing distance information vector, focal length information vector, manual mode vector, illuminance information vector ====1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 Form 1. and,,,,,,,
Matrix multiplication of B is performed to obtain X=C, which is output as a color temperature compensation signal. Regarding the computation of complex mode C, using the distance value l of the focusing distance information A, =1-l 0 0 0 0 0 1-l 0 0 0 0 0 l 0 0 0 0 0 l 0 0 0 0 0 α Form a diagonal matrix. Further, using the focal length value f of the focal length information F, a diagonal matrix of =1-f 0 0 0 0 0 0 0 0 1 0 0 0 0 f 0 0 0 0 f 0 0 0 0 f is formed. Then, the values of illuminance information B Lu, L _L , L _R , L _D are
Substitute μ=3Lu/L _R +L _L +L _D to calculate μ, and from this value of μ,

Form a diagonal matrix of [Equation]. Since strobe mode S and manual mode M are not used, a diagonal matrix of ==1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 is formed. And X=×
A color temperature compensation signal is output by performing matrix multiplication of M×××××. In addition, to explain the calculation process for obtaining the color temperature compensation signal X in the case where illuminance information B is input to the calculation circuit in composite mode C and the values of focusing distance information A and focal length information F are not input, first, the illuminance information B
Substitute the values L _U , L _L , L _R , L _D into μ=3Lu/L _R +L _L +L _D to find μ, and from this value of μ,

Form a diagonal matrix of [Equation]. Strobe mode S
Since the manual mode M is not used, a diagonal matrix of ==1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 is formed. And X=×
A color temperature compensation signal X is output by performing matrix multiplication of M×××××. The output X obtained in this way for manual mode M, strobe mode S, and composite mode C is a color temperature compensation signal, but the output X is amplified and controlled by an adjustment circuit (not shown) so that it falls within a predetermined range. It is used after the system has undergone gain adjustment and offset adjustment. FIG. 9f is a flowchart showing another specific example of the operation for obtaining the color temperature compensation signal, and in this example,
Using four pairs of color detectors, excluding the external detector G, and other parameters such as focusing distance information A, focal length information F, and the illuminance value Lu obtained from the color detectors in the upper region U, I am looking for a color temperature compensation signal. If it is determined in step that the power is on, input information is read in by scanning the switch in step. If it is determined in step that the mode is manual mode M, the color temperature setting value of the color temperature setting dial provided on the casing of the color television camera is output in step. If it is determined that the manual mode is not M, it is determined in a step whether or not the strobe mode S is selected, and if the strobe mode S is selected, the color temperature value of the strobe used in the step is output. In the step, the illuminance value Lu of the upper area obtained by adding the outputs from the pair of color detectors of the upper area U is set in advance.
It is determined whether or not it is larger than L _M , and if Lu > L _M , in the step, emphasis is placed on the outputs Lc and Rc of the color detectors of the left region L and right region R, Outputs X=(Lc+Rc)/2. Lu＞L _M
If not, the distance to the subject is known in the step, and if the distance l is greater than the preset distance l _M , emphasis is placed on the outputs of the color detectors in the left region L and right region R, and X = ( Lc＋
Rc)/2 is output. After that, in a step, it is determined whether the distance l to the subject is smaller than a preset distance _ln , and if l< _ln , emphasis is placed on the output of the color detector in the upper region U, and in the step X= Output Uc. Note that the magnitude relationship between the previously set values l _M and l _n is l _M >l _n . If l<l _n , then in step
The value f of the focal length information F is the preset value f _M
If f>f _M , the average value X=(Dc+Uc+Lc+Rc)/4 of the outputs of the four pairs of color detectors is output in step. f
> f _M , it is determined in step whether the focal length is smaller than a preset focal length value f _n , and if f < f _n , the output of the color detector in the upper area U is set as X = Uc. Output. If f<f _n , then in step the upper region U,
It is determined whether the output values of the color detectors in the right area R, left area L, and lower area D are approximately equal or not, and if they are approximately equal, X=(Dc+Uc+Lc+Rc)/4 is output. If the output values of the color detectors in the upper area U, right area R, left area L, and lower area D are not substantially equal, then in step The output of the detector is output as X=Uc, otherwise the average value of the outputs of the four pairs of color detectors is
+Uc+Lc+Rc)/4 is output. After the value of X to be output as the color temperature compensation signal has been calculated in this way, the process returns to step 1 again and this loop is repeated. FIG. 9g is a flowchart showing still another specific example of the operation for determining the color temperature compensation signal, and in this example, distance information A, focal length information F, and the illuminance value determined from the color detector in the upper region U are shown. Among Lu,
A color temperature compensation signal is obtained using the illuminance value Lu as a main parameter together with other parameters. If it is determined in step that the power is on, input information is read in by scanning the switch in step. If it is determined in step that the mode is manual mode M, the color temperature setting value of the color temperature setting dial provided on the casing of the color television camera is output in step. If it is determined that the mode is not manual mode M, it is determined in a step whether the mode is strobe mode S or not, and if it is strobe mode S, the color temperature value of the strobe used in step is output. In the step, the illuminance value Lu obtained by adding the outputs from the pair of color detectors in the upper region U is the preset value L _M
If Lu > L _M , in step, emphasis is placed on the outputs of the color detectors of the left region L and the right region R, and X = (Lc +
Rc)/2 is output. If Lu>L _M is not true, in step it is determined whether the output values of the color detectors in the upper area U, right area R, left area L, and lower area D are approximately equal, and if they are approximately equal, In step, output X=(Dc+Uc+Lc+Rc)/4. If they are not substantially equal, in step, the upper area U, the right area R, the left area L,
If the output values of the color detectors in the lower region D are not equal to each other, the average value X=(Dc+Uc+Lc+Rc)/4 of the outputs of the color detectors in the upper region U is output. After the value of X to be output as the color temperature compensation signal has been calculated in this way, the process returns to step 1 again and this loop is repeated. In addition, when using automatic tracking mode, which continuously and automatically adjusts the white balance while shooting, the color temperature of the light illuminating the subject is detected,
Color temperature compensation control must be performed quickly and accurately. Therefore, depending on the conditions of use of the color television camera and the subject to be photographed, in addition to the values detected by the four pairs of color detectors, distance setting information, focal length information, illuminance information, and values detected by the external detector may also be used. It is necessary to set evaluation criteria by appropriately weighting parameter values such as color temperature values. In addition, in a simple color television camera with a small number of control parameters, it is necessary to set weights and set evaluation criteria according to the most frequently used state when photographing a subject. Effects of the Invention As explained above, according to the present invention, the color temperature of incident light from multiple areas within the shooting screen or around the shooting screen is detected, so that the color temperature can be adjusted to an appropriate color temperature without being affected by a highly saturated subject. Compensation can be made. Also,
By referring to the illuminance information of at least a portion of the photographic screen, it is possible to find out the condition of the photographic screen, especially parts of the screen where the illuminance is extremely different, and weight the color temperature information of each area according to this illuminance information. By determining this, more appropriate color temperature compensation can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a color temperature corrector of a conventional color television camera, Fig. 2 is a block diagram of a color filter, and Fig. 3 is a block diagram of a color temperature corrector of another conventional color television camera. Figure 4 is a spectral energy distribution curve diagram, Figure 5 is a spectral characteristic diagram of red and blue signals according to color temperature signals, Figure 6 is a diagram showing gain correction amounts of red and blue signals according to color temperature, Figure 7a
7e to 7e explain the basic concept of color temperature detection used in the embodiment of the present invention, and FIG. 7a
7b is a perspective view of the object shown in FIG. 7a, and FIG. 7c is a view of the object and its surroundings viewed from the image pickup tube side. , FIG. 7d is a block diagram of a color temperature compensation circuit, FIG. 7e is a cross-sectional view of a zoom lens system in which a color detector is arranged, and FIGS.
Figure f explains a method of detecting color temperature in multiple areas. Figure 8a is a side sectional view of the subject and main parts of the color television camera, and Figure 8b is the same as Figure 8a. FIG. 8c is a perspective view of what is shown, FIG. FIG. 8e shows a block diagram of a color temperature signal detection circuit including an evaluation judgment circuit, FIGS. 8f to 8h show evaluation judgment flowcharts for obtaining a color temperature compensation signal, and FIGS. Figure 9f shows an embodiment of the present invention, Figure 9a is a side view of an embodiment in which four pairs of color detectors are arranged in a zoom lens system, and Figure 9b shows the output from the color detectors. FIG. 9c is a circuit block diagram of the embodiment shown in FIG. 9a, and FIG. 9d is a circuit block diagram for determining color temperature and illuminance from
9 is a circuit diagram in which various parameters are input, and FIG.
Figure f is a flowchart of another specific example of the operation of outputting a color temperature compensation signal, and Figure 9g is a flowchart of still another specific example of the operation of outputting a color temperature compensation signal when illuminance information is the main parameter. A flowchart related to this is shown. In Fig. 9c, 31a and 31b, 31b and 32b, 31c and 32c, 31d and 32d are four pairs of color detectors, 36a and 36b are external color detectors, 71 is a switching circuit, and 72 is an AD converter. circuit, 73 is an arithmetic circuit, 74 is a DA conversion circuit, 4
5 is an evaluation judgment circuit, 58 is a distance signal generator, 59
is focal length signal generator, S is strobe mode, M
indicates manual mode.

Claims (1)

[Scope of Claims] 1. Imaging means that converts object light transmitted through a photographic lens into a color image signal, and a gain that controls the gains of at least two or more color signals in the color image signal using control signals for each color signal. a control means; a plurality of color temperature detection means for respectively detecting the color temperature of incident light from a photographing screen by the photographing means or a plurality of areas around the photographing screen; illuminance detection means for detecting illuminance information; and weighted synthesis of the outputs of the plurality of color temperature detection means to generate the color temperature-specific control signal in order to perform color temperature compensation of the color signal; A color temperature compensating device for a color television camera, comprising: color temperature compensating means for supplying a color temperature to a color temperature detecting means, and changing weighting of the plurality of color temperature detecting means according to the illuminance information.