JP2007129610A - High luminance compression circuit, high luminance compression processing method, and television camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high luminance compression circuit, a high luminance compression processing method, and a television camera for naturally expressing colors of a high luminance object while preventing a hue from varying before and after a high luminance compression process. <P>SOLUTION: When a signal level (L) of a maximum-level signal among three primary color signals exceeds a predetermined level (K); the maximum-level signal is subject to the compression process, and signal levels (X1, X2) of the residual primary color signals are adjusted. While ratios of finite differences among the three primary color signals (the ratio of D1 and D2 being the finite differences before the compression process, as well as the ratio of D1' and D2' being the finite differences after the compression process) are kept constant, a magnitude of the finite differences (D1' and D2') is changed according to luminance of the object. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-intensity compression circuit and high-intensity compression processing method for performing high-intensity compression processing on three primary color signals, and a television camera using the circuit or method.

  The dynamic range of three primary color signals obtained from a solid-state imaging device such as a CCD provided in a television camera usually has a linear characteristic up to about several hundred percent. However, since the signal level of the video signal output from the camera is regulated to a maximum of about 110%, conventionally, compression processing (high luminance compression processing) has been performed on high luminance portions exceeding a predetermined level. It has been broken.

However, when independent compression processing is performed on each of the signals of the three primary colors, there is a problem that the hue changes before and after the processing because there is no correlation in each signal processing. Therefore, for example, as described in Patent Document 1, a technique has been proposed in which when any of the three primary color signals exceeds a predetermined level, compression processing is simultaneously performed on all the signals.
JP-A-10-257515

  The video signal is saturated when the brightness of the subject increases, and eventually converges to colorless white. In the above-described conventional technology, it is possible to suppress a change in hue by simultaneously performing compression processing on each of the signals of the three primary colors. However, since such processing functions to maintain color saturation, Even when the brightness increases, the color saturation does not decrease. That is, in the prior art, since the color component remains even when the luminance of the subject is increased, the color of the high luminance subject may not be converged to white and may appear unnatural.

  Therefore, the object of the present invention is to solve the above-mentioned problems, and to prevent the hue from changing before and after the high-intensity compression processing, while naturally expressing the color of the high-intensity subject, The object is to provide a high-intensity compression processing method and a television camera.

  In order to solve the above problems, in the high-intensity compression circuit according to the present invention, a maximum level signal extraction circuit that extracts a maximum level signal having a maximum signal level from the input three primary color signals, A compression circuit that compresses the maximum level signal when the extracted maximum level signal exceeds a predetermined level, and calculates a difference between each of the input three primary color signals and the extracted maximum level signal Each of the calculated difference using the calculated compression coefficient, a compression coefficient calculation circuit that calculates a compression coefficient corresponding to the signal level of the extracted maximum level signal, and A differential compression circuit that performs compression processing on the difference, calculates a difference between each of the compressed difference and the compressed maximum level signal, and compresses the calculation result to the high-intensity compression Characterized in that it comprises a second differential operation circuit for outputting a three primary color signal after sense.

  In the high-intensity compression processing method according to the present invention, the maximum level signal having the maximum signal level is extracted from the three primary color signals, and the maximum level signal is extracted when the extracted maximum level signal exceeds a predetermined level. The level signal is compressed, the signal level of the remaining primary color signals is adjusted, and the magnitude of the difference is changed according to the luminance of the subject while keeping the ratio of the differences among the three primary color signals constant. To do.

  In the television camera according to the present invention, the high luminance compression circuit, the three primary color signal generation means for generating the three primary color signals to be input to the high luminance compression circuit, and the high luminance compression circuit. And a signal processing circuit for processing the output three primary color signals.

  In the television camera according to the present invention, the three primary color signals obtained by color-separating the imaging light are photoelectrically converted to generate the three primary color signals, and the generated three primary color signals are subjected to signal processing. In the television camera for output, the high luminance compression processing method described above is used for signal processing of the three primary color signals.

  In the high-intensity compression circuit, high-intensity compression processing method, and television camera according to the present invention, the difference is reduced as the luminance of the subject increases while the ratio of the difference between the signals of the three primary colors is kept constant. be able to. Therefore, it is possible to prevent the hue from changing before and after the high-intensity compression process, and it is possible to reduce the color saturation as the subject brightness increases. Can be expressed.

  The best mode for carrying out a high-intensity compression circuit, a high-intensity compression processing method, and a television camera according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a television camera according to the present invention. In FIG. 1, the configuration of the television camera is shown with a focus on a circuit relating to video signal processing.

  In FIG. 1, reference numeral 1 denotes a television camera, and reference numeral 2 denotes an imaging lens attached to the television camera 1. The television camera 1 includes a color separation prism 3 and three CCDs 4R, 4G, and 4B as three primary color signal generation means. That is, the television camera 1 according to this embodiment is a three-plate camera.

  Imaging light of a subject (not shown) incident from the imaging lens 2 is separated into three primary colors R (red), G (green), and B (blue) by the color separation prism 3. The R, G, and B primary color lights color-separated by the color separation prism 3 are photoelectrically converted into R, G, and B primary color signals (analog signals) by the CCDs 4R, 4G, and 4B, respectively.

  The three primary color signals output from the CCDs 4R, 4G, and 4B are amplified by the preamplifier circuit 6 after thermal noise and 1 / f noise are removed by the CDS (correlated double sampling) circuit 5. The three primary color signals output from the preamplifier circuit 6 are further gain-controlled and amplified by an AGC (automatic gain control) circuit 7, and then converted into a digital signal by an A / D conversion circuit 8, and a DSP (digital signal processing). Input to the circuit 9. The DSP circuit 9 performs processing such as contour correction, gamma correction, high-intensity compression, and encoding of the input three primary color signals. The three primary color signals that have been subjected to the above processes in the DSP circuit 9 are converted back into analog signals in the D / A conversion circuit 10 and output to a VTR, a monitor, etc. (not shown). As described above, the television camera 1 photoelectrically converts the three primary color lights obtained by color-separating the imaging light to generate the three primary color signals, performs signal processing on the generated three primary color signals, and outputs them as video signals. .

  FIG. 2 is a block diagram showing the configuration of the high-intensity compression circuit provided in the DSP circuit 9. The illustrated high-intensity compression circuit 11 is a part of the DSP circuit 9, and performs high-intensity compression processing, specifically, knee compression processing and white clip processing on the input three primary color signals.

  Here, before continuing the description of FIG. 2, the outline of the operation of the high-intensity compression circuit 11 will be described.

  FIG. 3 is a diagram illustrating the signal levels of the three primary color signals that have been subjected to the high luminance compression processing by the high luminance compression circuit 11.

The meanings of symbols used in the following description are shown below.
K: Knee point (arbitrary setting)
W: White clip level (arbitrary setting)
C: Saturation convergence level (arbitrary setting)
L: signal level X1, X2 of the maximum level signal among the three primary color signals: signal level D1: primary color signal other than L: L-X1 when L = K (ie, K-X1)
D2: L-X2 when L = K (ie, K-X2)
L ′: L after knee compression and white clip processing
X1 ′, X2 ′: X1, X2 after knee compression and white clip processing
D1 ': L'-X1'
D2 ': L'-X2'

  As shown in FIG. 3, the maximum level signal having the maximum signal level among the three primary color signals input to the high-intensity compression circuit 11 is knee-compressed when the knee point K (predetermined level) is exceeded. When the white clip level W (second predetermined level) higher than K is exceeded, white clip processing is performed.

  At this time, if any processing is not performed on the remaining primary color signals excluding the maximum level signal, the difference ratio between the signals changes, and the hue changes. Moreover, if the ratio of the difference is simply kept constant to prevent the hue from changing, the saturation of the color is maintained even if the brightness of the subject is increased, and the color component remains, so that the color of the high brightness subject is changed. In some cases, it did not converge to white and looked unnatural.

  Therefore, in the high-intensity compression circuit 11 according to the present invention, when the maximum level signal exceeds the knee point K, the maximum level signal is compressed and the signal levels X1 and X2 of the remaining primary color signals are adjusted. While the ratio of the differences between the primary color signals is kept constant, the magnitude of the difference is changed according to the luminance of the subject. Specifically, the difference is decreased as the luminance of the subject is higher.

  The above method will be described in detail. In order to converge the color to white as the luminance of the subject increases, it is necessary to gradually decrease D1 ′ and D2 ′ in the region of L> K where high luminance compression processing is performed. is there. That is, the difference between the signals has a maximum value at D1 and D2 when L = K. D1 ′ and D2 ′ can be generated by compressing D1 and D2 as shown in FIG. 4, but this requires a compression coefficient proportional to the size of L.

Therefore, the saturation convergence level C is set as a parameter used for calculating the compression coefficient, and the compression coefficient T is calculated according to the following equation 1.
T = (C−L) / (C−K) Equation 1
However, T = 0 when L> C.

  The saturation convergence level C is specifically the signal level of the maximum level signal when the levels of the three primary color signals are increased and all the signals are finally saturated. That is, when the three primary color signals reach the saturation convergence level C, the color saturation becomes zero.

As is apparent from Equation 1, the compression coefficient T is a function of L and changes linearly with respect to changes in L. D1 ′ and D2 ′ can be expressed by the following formulas 2 and 3, respectively.
D1 ′ = D1 × T
= D1 × (CL) / (C−K) Equation 2
D2 ′ = D2 × T
= D2 × (CL) / (C−K) Equation 3

The values of D1 and D2 vary depending on the subject, but as can be understood from FIG. 3, the following equations are established for D1 and D2.
D1: (L−X1) = K: L Formula 4
That is,
D1 = K (L−X1) / L Equation 5
From Equation 2 above,
D1 ′ = {K (L−X1) / L} × {(C−L) / (C−K)} Expression 6
Similarly,
D2: (L−X2) = K: L Expression 7
That is,
D2 = K (L−X2) / L Expression 8
From Equation 3 above,
D2 ′ = {K (L−X2) / L} × {(C−L) / (C−K)} Equation 9

Since the ratio of D1 ′ obtained by Equation 6 and D2 ′ obtained by Equation 9 is equal to that of D1 and D2, X1 ′ and X2 ′ are calculated from Equation 10 and Equation 11 below, respectively. Thus, it is possible to obtain three primary color signals whose hue does not change before and after the high luminance compression process.
X1 ′ = L′−D1 ′ Expression 10
X2 ′ = L′−D2 ′ Expression 11

  Based on the above, the configuration of the high-intensity compression circuit 11 shown in FIG. 2 will be described.

  As shown, the high-intensity compression circuit 11 includes a maximum level signal extraction circuit 12, a knee compression circuit 13, a white clip circuit 14, difference calculation circuits (first difference calculation circuits) 15R, 15G, and 15B, and compression coefficients. An arithmetic circuit 16, differential compression circuits 17R, 17G, and 17B, and differential arithmetic circuits (second differential arithmetic circuits) 18R, 18G, and 18B are provided. The difference calculation circuits 15R, 15G, and 15B, the difference compression circuits 17R, 17G, and 17B, and the difference calculation circuits 18R, 18G, and 18B are provided for the signals of the three primary colors, respectively.

  The maximum level signal extraction circuit 12 receives three primary color signals Rin, Gin, and Bin that have undergone contour correction and gamma correction. The maximum level signal extraction circuit 12 extracts the maximum level signal having the maximum signal level from the input three primary color signals Rin, Gin, and Bin.

  The extracted maximum level signal is input to the knee compression circuit 13. When the signal level L of the maximum level signal exceeds the knee point K, the knee compression circuit 13 performs compression processing (knee compression) on the maximum level signal. The maximum level signal Lk output from the knee compression circuit 13 is input to the white clip circuit 14, where a portion exceeding the white clip level W (eg, 110% of the rated signal) is clipped.

  The three primary color signals Rin, Gin, and Bin are input to the difference calculation circuits 15R, 15G, and 15B, respectively, and the maximum level signal extracted by the maximum level signal extraction circuit 12 is input. Although not shown, the knee point K is input to the difference calculation circuits 15R, 15G, and 15B. The difference calculation circuits 15R, 15G, and 15B calculate the difference between the input three primary color signals and the maximum level signal, specifically, the three primary color signals when L = K according to the above-described Expressions 5 and 8. Calculate the difference between the maximum level signals. That is, the difference calculation circuits 15R, 15G, and 15B subtract the signal level of the three primary color signals input from the signal level L of the maximum level signal, multiply the obtained value by the knee point K, and obtain the obtained value. Further, by dividing by L, the difference between the three primary color signals and the maximum level signal when L = K is calculated.

  In the following, an example will be described in which the signal level of Rin corresponds to L described above (that is, Rin is the maximum level signal), and the signal levels of Gin and Bin correspond to X1 and X2, respectively.

  Since the difference calculation circuit 15R receives Rin (that is, the maximum level signal) of the three primary color signals, the calculation result is zero. On the other hand, since Gin and Bin whose signal levels correspond to X1 and X2 are input to the difference calculation circuits 15G and 15B, the calculation results are values corresponding to the above-described D1 and D2, respectively.

  The maximum level signal extracted by the maximum level signal extraction circuit 12 is also input to the compression coefficient calculation circuit 16. The compression coefficient calculation circuit 16 calculates a compression coefficient T corresponding to the signal level L of the maximum level signal.

  FIG. 5 is a block diagram showing the configuration of the compression coefficient calculation circuit 16. As shown in FIG. 5, the compression coefficient calculation circuit 16 includes difference calculation circuits 16a and 16b and a divider 16c.

  The difference calculation circuit 16a receives the maximum level signal and the saturation convergence level C from the saturation convergence level storage unit 20, and the difference (C−) between the saturation convergence level C and the signal level L of the maximum level signal. L) is calculated. Further, the difference calculation circuit 16b receives the saturation convergence level C from the saturation convergence level storage unit 20 and the knee point K from the knee point storage unit 21, and determines the saturation convergence level C and the knee point K. The difference (C−K) is calculated.

  The calculation results of the difference calculation circuits 16a and 16b are input to the divider 16c. The divider 16c calculates the compression coefficient T according to the above equation 1. That is, the divider 16c divides the calculation result (CL) of the difference calculation circuit 16a by the calculation result (CK) of the difference calculation circuit 16b, and outputs the obtained quotient as the compression coefficient T. Accordingly, the compression coefficient T is a function of L and changes linearly with respect to the change of L. Specifically, the value of T decreases as L increases. More specifically, the value of T decreases as L approaches C, and T becomes 0 when L matches C.

  Returning to the description of FIG. 2, the difference compression circuits 17R, 17G, and 17B receive the calculation results of the difference calculation circuits 15R, 15G, and 15B, respectively, and the compression coefficient T calculated by the compression coefficient calculation circuit 16 Entered. The differential compression circuits 17R, 17G, and 17B use the compression coefficient T to perform compression processing on the calculation results of the differential calculation circuits 15R, 15G, and 15B. Specifically, the above-described Expressions 2 and 3 are used. In this manner, the calculation results of the difference calculation circuits 15R, 15G, and 15B are multiplied by the compression coefficient T.

  As described above, since the output of the difference calculation circuit 15R is 0, the output of the difference compression circuit 17R is also 0. On the other hand, since the outputs of the difference calculation circuits 15G and 15B are values corresponding to D1 and D2, respectively, the outputs of the difference compression circuits 17G and 17B are values corresponding to the aforementioned D1 ′ and D2 ′, respectively. As described above, since the compression coefficient T decreases as L increases, D1 ′ and D2 ′ also decrease as L increases, and becomes 0 when L matches C.

  The calculation results of the difference compression circuits 17R, 17G, and 17B are input to the difference calculation circuits 18R, 18G, and 18B, respectively. Further, the output of the white clip circuit 14 is also input to the difference calculation circuits 18R, 18G, and 18B. The difference calculation circuits 18R, 18G, and 18B obtain the calculation results of the difference compression circuits 17R, 17G, and 17B from the signal level L ′ of the maximum level signal that has been subjected to knee compression and white clip processing in accordance with Expressions 10 and 11 described above. Subtract and find the difference between them. The calculation results of the difference calculation circuits 18R, 18G, and 18B are output from the high luminance compression circuit 11 as the three primary color signals Rout, Gout, and Bout after the high luminance compression processing, respectively. The three primary color signals Rout, Gout, Bout output from the high-intensity compression circuit 11 are input to a signal processing circuit such as an encoder (not shown) in the DSP 9 or the D / A conversion circuit 10 and output to a VTR or a monitor. Further processing is performed.

  Since the output of the differential compression circuit 17R is 0, the calculation result of the differential calculation circuit 18R, that is, the signal level of Rout is L ′. On the other hand, since a value corresponding to D1 ′ is input to the difference calculation circuit 18G, the signal level of Gout becomes a value corresponding to the above-described X1 ′. Further, since a value corresponding to D2 ′ is input to the difference calculation circuit 18B, the signal level of Bout is a value corresponding to the above-described X2 ′. As described above, D1 ′ and D2 ′ (that is, the difference between the three primary color signals Rout, Gout, and Bout) become smaller as L approaches the saturation convergence level C, and becomes 0 when L matches C. Therefore, the video signal output from the high-intensity compression circuit 11 decreases in color saturation as the luminance of the subject increases, and eventually converges to white.

  The ratio of D1 ′ and D2 ′, which are the differences between the three primary color signals Rout, Gout, and Bout after the high-intensity compression processing, is the difference between D1 and D2 that are the differences between the three primary color signals Rin, Gin, and Bin before the processing. Since the ratio matches, the hue does not change before and after the high luminance compression process.

  If the white clip circuit 14 is not provided in FIG. 2, the output of the knee compression circuit 13 is input to the difference calculation circuits 18R, 18G, and 18B instead of the output of the white clip circuit 14, and the knee compression processing is performed. The calculation result of the differential compression circuits 17R, 17G, and 17B may be subtracted from the signal level Lk of the maximum level signal, and the difference between them may be obtained. In that case, in the above example, the signal levels of the three primary color signals Rout, Gout, and Bout after the high-intensity compression processing are Lk, X1 ′, and X2 ′, respectively.

  As described above, in the high luminance compression circuit 11 according to the present invention, the maximum level signal extraction circuit that extracts the maximum level signal having the maximum signal level from the input three primary color signals Rin, Gin, Bin. 12, a knee compression circuit 13 that performs knee compression on the maximum level signal when the extracted maximum level signal exceeds the knee point K, each of the input three primary color signals, and the extracted maximum Difference between level signals (more specifically, the difference between each of the input three primary color signals and the predetermined level when the extracted maximum level signal is the knee point K) D1 and D2 An arithmetic circuit 15R, 15G, 15B, a compression coefficient arithmetic circuit 16 for calculating a compression coefficient T according to the signal level L of the extracted maximum level signal, and the calculated pressure The differential compression circuits 17R, 17G, and 17B that perform compression processing on each of the calculated differences D1 and D2 by using the coefficient T, and the compression processing of each of the compressed differences D1 ′ and D2 ′. Difference calculation circuits 18R, 18G, and 18B that calculate the differences Lk, X1 ′, and X2 ′ from the maximum level signal and output the calculation results as the three primary color signals Rout, Gout, and Bout after the high-intensity compression processing. With this configuration, the difference can be reduced as the luminance of the subject increases while the ratio of the difference between the three primary color signals is kept constant. Therefore, the hue can be prevented from changing before and after the high-intensity compression process, and the saturation of the color decreases as the subject brightness increases, so that the color of the high-intensity subject can be expressed naturally. Can do.

  Further, since the compression coefficient calculation circuit 16 is configured so that the calculation result expressed by (CL) / (CK) is the compression coefficient T, color saturation is achieved as the luminance of the subject increases. Since the degree can be reduced more naturally, the color of the high-luminance subject can be expressed more naturally.

  And a white clip circuit 14 for clipping the compressed maximum level signal when the compressed maximum level signal exceeds a white clip level W higher than the knee point K. 18R, 18G, and 18B calculate differences L ′, X1 ′, and X2 ′ between each of the compressed differences D1 ′ and D2 ′ and the clipped maximum level signal, and the calculation result is the high luminance. Since the three primary color signals Rout, Gout, and Bout after compression processing are output, the same effect as described above can be obtained even when the maximum level signal after compression processing is further clipped. be able to.

  In the high-intensity compression processing method according to the present invention, when the signal level L of the maximum level signal in the three primary color signals Rin, Gin, Bin exceeds the knee point K, knee compression is performed on the maximum level signal. In addition to performing processing, the signal levels X1 and X2 of the remaining primary color signals are adjusted, and the difference ratio between the three primary color signals (the ratio between D1 and D2, which is the difference before the compression process, and D1 which is the difference after the compression process). The ratio (D1 ′ and D2 ′) is changed according to the luminance of the subject while keeping the ratio of ′ and D2 ′ constant. More specifically, the difference is increased as the luminance of the subject is higher. Because it is configured, it can prevent hue changes before and after high-intensity compression processing, and the saturation of the color decreases as the subject brightness increases, so the color of the high-intensity subject is naturally expressed To do It can be.

  Further, in the television camera 1 according to the present invention, since the high luminance compression circuit 11 and the high luminance compression processing method described above are used, the same effect as described above can be obtained.

  In the embodiment of the present invention, the signal level of Rin corresponds to L, and the signal levels of Gin and Bin correspond to X1 and X2, respectively. However, the magnitude relationship between the signal levels is limited to that. It is not something.

  Further, the configuration of the television camera 1 shown in FIG. 1 is an exemplification, and each configuration excluding the high-intensity compression circuit 11 may be appropriately changed according to the use and specification of the camera.

It is a block diagram showing the structure of the television camera which concerns on this invention. FIG. 2 is a block diagram illustrating a configuration of a high-intensity compression circuit provided in the DSP circuit illustrated in FIG. 1. FIG. 3 is a diagram illustrating signal levels of three primary color signals subjected to high luminance compression processing by the high luminance compression circuit shown in FIG. 2. It is a figure showing the difference between the three primary color signals input into the high-intensity compression circuit shown in FIG. FIG. 3 is a block diagram illustrating a configuration of a compression coefficient calculation circuit illustrated in FIG. 2.

Explanation of symbols

  1: television camera, 3: color separation prism (three primary color signal generation means), 4R, 4G, 4B: CCD (three primary color signal generation means), 10: D / A conversion circuit (signal processing circuit), 11: high Luminance compression circuit, 12: maximum level signal extraction circuit, 13: knee compression circuit (compression circuit), 14: white clip circuit (clip circuit), 15R, 15G, 15B: difference calculation circuit (first difference calculation circuit), 16: compression coefficient arithmetic circuit, 17R, 17G, 17B: differential compression circuit, 18R, 18G, 18B: differential arithmetic circuit (second differential arithmetic circuit)

Claims (8)

In a high-intensity compression circuit that performs high-intensity compression processing on the input three primary color signals,
A maximum level signal extraction circuit for extracting a maximum level signal having a maximum signal level from the inputted three primary color signals;
A compression circuit that compresses the maximum level signal when the extracted maximum level signal exceeds a predetermined level;
A first difference calculation circuit for calculating a difference between each of the input three primary color signals and the extracted maximum level signal;
A compression coefficient calculation circuit for calculating a compression coefficient according to the signal level of the extracted maximum level signal;
A differential compression circuit that performs compression processing on each of the computed differences using the computed compression coefficient;
A second difference calculation circuit that calculates a difference between each of the compressed difference and the compressed maximum level signal, and outputs a calculation result as the three primary color signals after the high-intensity compression process;
A high-intensity compression circuit comprising: In a high-intensity compression circuit that performs high-intensity compression processing on the input three primary color signals,
A maximum level signal extraction circuit for extracting a maximum level signal having a maximum signal level from the inputted three primary color signals;
A compression circuit that compresses the maximum level signal when the extracted maximum level signal exceeds a predetermined level;
A first difference calculation circuit for calculating a difference between each of the inputted three primary color signals and the predetermined level when the extracted maximum level signal is the predetermined level;
A compression coefficient calculation circuit for calculating a compression coefficient in accordance with the signal level of the extracted maximum level signal;
A differential compression circuit that performs compression processing on each of the computed differences using the computed compression coefficient;
A second difference calculation circuit that calculates a difference between each of the compressed difference and the compressed maximum level signal, and outputs a calculation result as the three primary color signals after the high-intensity compression process;
A high-intensity compression circuit comprising: The high-intensity compression circuit according to claim 2,
When the predetermined level is K, the signal level of the extracted maximum level signal is L, and the signal level of the maximum level signal when all of the input three primary color signals are saturated is C, the compression coefficient calculation The circuit is a high-intensity compression circuit characterized in that an operation result represented by (CL) / (CK) is used as the compression coefficient. In the high-intensity compression circuit in any one of Claim 1 to 3,
A clipping circuit that clips the compressed maximum level signal when the compressed maximum level signal exceeds a second predetermined level higher than the predetermined level;
And the second difference calculation circuit calculates a difference between each of the compressed difference and the clipped maximum level signal, and outputs a calculation result of the three primary color signals after the high luminance compression process. Output as a high-intensity compression circuit.   In a high-intensity compression processing method for performing high-intensity compression processing on three primary color signals, a maximum level signal having a maximum signal level is extracted from the three primary color signals, and the extracted maximum level signal exceeds a predetermined level. When the maximum level signal is compressed, the signal level of the remaining primary color signals is adjusted, and the magnitude of the difference is changed according to the luminance of the subject while keeping the ratio of the differences among the three primary color signals constant. A high-intensity compression processing method. In the high-intensity compression processing method according to claim 5,
The high-intensity compression processing method, wherein the difference is reduced as the luminance of the subject is higher. A high-intensity compression circuit according to any one of claims 1 to 4,
Three primary color signal generation means for generating three primary color signals input to the high luminance compression circuit;
A signal processing circuit for processing the three primary color signals output from the high-intensity compression circuit;
A television camera comprising: In a television camera that photoelectrically converts three primary color lights obtained by color-separating imaging light to generate a three primary color signal, performs signal processing on the generated three primary color signals, and outputs the signal.
7. A television camera using the high-intensity compression processing method according to claim 5 or 6 for signal processing of the three primary color signals.

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