JPH0888863A - High brightness compression device - Google Patents

Abstract

(57) [Summary] [Structure] The maximum value detection circuit 2 detects the maximum level of the image data of the three primary colors supplied from the outside, and the comparator 4 detects the level of this image data and the high brightness. The level of the knee point data indicating the level of the imaging data to be compressed is compared. At the same time, the subtractor 5 to the multiplier 11 simultaneously perform a predetermined high-intensity compression process on the image data for each color, and supply these to the changeover switches 12 to 14 to which the input image data are supplied as they are. To do. Then, when the comparator 4 detects that the level of the maximum level imaging data exceeds the level of the knee point data, each of the changeover switches 12 based on the output from the comparator 4. 14 to 14 select and output the image pickup data subjected to the high brightness compression processing. [Effect] The high-intensity compression processing can be performed while maintaining the ratio at the time of inputting each image pickup data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-intensity compression device suitable for use in, for example, a video camera device, a camera device, etc., and in particular, one of RGB image pickup signals has a level for performing high-intensity compression processing. When a certain knee point level is exceeded, the high-intensity compression processing is performed on the other image pickup signals at the same time to maintain the ratio of each image pickup signal. The present invention relates to a high-intensity compression device that performs high-intensity compression processing as it is to improve color reproducibility.

[0002]

2. Description of the Related Art Conventionally, there is known a so-called three-plate type camera device in which a CCD image sensor for each color of red (R), G (green) and B (blue) images a subject and outputs the image pickup signal. ing. The dynamic range of the image pickup signal obtained by the CCD image sensor for each color is usually about 600% and has a linear characteristic from the low range to the high range, but the maximum output of the camera device itself is, for example, the brightness. Since it is specified in the signal such as 110% at maximum, the above C
In the image pickup signal obtained from the CD image sensor, the signal component having the maximum output or more is cut and transmitted.

Here, when an image pickup signal having the above-mentioned linear characteristic is cut as it is at the maximum output and transmitted, and an image corresponding to this image pickup signal is displayed on a monitor, for example, the desired subject being displayed is clearly displayed. When the brightness level is increased to be shown, as described above, since the image signal has the signal component of the maximum output or more cut off, the bright part such as the background of the desired subject is displayed in white. A so-called color skipping phenomenon may occur.

Therefore, in order to reduce such a color jump phenomenon, the camera device is provided with a high-intensity compression device.

This high-intensity compression device has a knee point for performing high-intensity compression, which is a common level for the image pickup signals for each color as shown in FIG. are doing. And CCD for each color
Each time the level of the image pickup signal for each color obtained from the image sensor reaches the above-mentioned knee point level as shown in FIG. 7, the image pickup signal for each color having a linear characteristic until then is separately provided. Is subjected to high-luminance compression processing so as to reduce the inclination of each characteristic, and is output.

As a result, it is possible to increase the information amount of the high frequency component between the knee point and the maximum output level. Therefore, even if an image corresponding to the image pickup signal subjected to the high-brightness compression processing is displayed with a higher brightness level, the image corresponding to the high-frequency component is displayed to the limit because the information amount of the high-frequency component is large. It is possible to suppress the above-mentioned color skip phenomenon.

[0007]

However, in the conventional high-intensity compression device, the above-described high-intensity compression processing is separately performed for each of the RGB image pickup signals. There is a problem that the ratio of the image pickup signals for each color changes before and after the high brightness compression process. When the ratio of the image pickup signal for each color changes, there occurs a problem of color reproducibility in which the hue of the subject at the time of image pickup is different from the hue at the time of display.

The present invention has been made in view of the above problems, and it is possible to improve the color reproducibility by preventing the ratio of the image pickup signals for each color from changing before and after the high luminance compression processing. A high brightness compression device is provided.

[0009]

A high-intensity compression apparatus according to the present invention is a maximum level detecting means for detecting maximum level image information from image information of three primary colors supplied from the outside, and the maximum level detecting means. The level of the image information detected by the means and the high-intensity compression level indicating the level of the image information to be subjected to the high-intensity compression processing are compared, and when the level of the image information is equal to or higher than the high-intensity compression level, And high-luminance compression means for simultaneously performing predetermined high-luminance compression processing on the image information of the three primary colors.

In addition to the above-described high-intensity compression device, the high-intensity compression device according to the present invention separately performs predetermined high-intensity compression processing on each of the above-mentioned image information that exceeds the above-mentioned high-intensity compression level. The high-intensity compression section to be applied, each image information that has been individually subjected to high-intensity compression processing by the high-intensity compression section, and each image information that has been simultaneously subjected to high-intensity compression processing by the high-intensity compression means are added. And adding means for processing and outputting.

[0011]

In the high brightness compression apparatus according to the present invention, when the image information of the three primary colors is supplied from the outside, the maximum level detecting means is
The image information having the highest level among the above image information is detected, and this level is detected.

The high-intensity compression means compares the level of image information detected by the maximum level detection means with the high-intensity compression level indicating the level of image information to be subjected to high-intensity compression processing. If the level of the image information is higher than the high-intensity compression level, the image information is highly likely to have a high band component equal to or higher than the maximum output level. Then, a predetermined high brightness compression process is performed. At the same time, the high-intensity compression means performs the same high-intensity compression processing on other image information.

As a result, the high-intensity compression processing is simultaneously applied to the image information of the three primary colors, so that the high-intensity compression processing is performed while maintaining the ratio of the image information of the three primary colors at the time of input. be able to. Therefore, it is possible to reduce the deviation between the hue of the subject at the time of image capturing and the hue at the time of displaying, and it is possible to improve the color reproducibility.

Next, in the high-intensity compression apparatus according to the present invention, the high-intensity compression section individually performs a predetermined high-intensity compression process on each piece of image information that exceeds the high-intensity compression level, and these are processed. Supply to the adding means.

Separately from this, the above-mentioned addition means is supplied with image information from the above-mentioned high-intensity compression device, which is obtained by simultaneously subjecting each image information to high-intensity compression processing.

The adding means combines the image information that has been individually subjected to the high-intensity compression processing by the high-intensity compression section and the image information that has been simultaneously subjected to the high-intensity compression processing by the high-intensity compression means. Add and output.

Thus, it is possible to prevent the inconvenience of excessive coloring that occurs when the above-mentioned respective image information is simultaneously subjected to the high-intensity compression processing, and the high-intensity compression processing that provides a more natural display image is provided. Can be possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the high-intensity compression apparatus according to the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, a high-intensity compression apparatus 1 according to a first embodiment of the present invention is a digital image pickup data for red (R) color and a digital image data for green (G) which are supplied from the outside. Maximum value detection circuit 2 that detects the maximum data level from the image data and blue (B) color image data and outputs maximum value data, and maximum value data from the maximum value detection circuit 2 The reciprocal conversion circuit 3 that forms and outputs the reciprocal of the above is compared with the maximum value data and the comparator 4 that outputs the comparison data by comparing the knee point data indicating the knee point that is the level for performing the high-intensity compression processing. Have

Further, the high-intensity compression device 1 subtracts the knee slope data indicating the knee slope for performing the predetermined high-intensity compression processing from the 1 data indicating the slope when the high-intensity compression processing is not performed. The maximum value data, which is the reciprocal of the reciprocal conversion circuit 3, is added to the multiplier 5, the knee point data, the multiplier 6 that multiplies the subtracted output from the subtractor 5, and the multiplication output from the multiplier 6. It has a multiplier 7 for performing a multiplication process, and an adder 8 for performing an addition process on the multiplication output from the multiplier 7 and the knee slope data.

The high-intensity compression apparatus 1 further includes a B multiplier 9 for multiplying the addition output from the adder 8 and the B image data, and the addition output from the adder 8 and the G output. A multiplier 10 for G that multiplies the imaged data,
It has an addition output from the adder 8 and an R multiplier 11 that multiplies the R imaging data.

Further, the high-intensity compression device 1 is switched and controlled in accordance with the comparison data from the comparator 4, and outputs the B image data and the multiplication output from the B multiplier 9 by switching them B. Switching switch 12 for G, and a G switching switch 13 for switching and outputting the G imaging data and the multiplication output from the G multiplier 10 which are similarly switched and controlled according to the comparison data from the comparator 4. Similarly, it has an R changeover switch 14 which is switched and controlled according to the comparison data from the comparator 4 and switches and outputs the R imaging data and the multiplication output from the R multiplier 11.

Further, the high-intensity compression apparatus 1 delays the image pickup data for each color by a time required for the arithmetic processing performed between the maximum value detection circuit 2 and the R multiplier 11. The delay circuits 15 to 17 are provided.

Such a high-intensity compression device can be applied to a camera device as shown in FIG.

That is, this camera device is a so-called 3
It is a plate type camera device, which receives R image pickup light, G image pickup light, and B image pickup light from among the image pickup lights to form R image pickup data, G image pickup data, and B image pickup data. CCD image sensor 30R to 30B for each color to be output
And an amplifier circuit 33R to 33B for each color that amplifies the image pickup data for each color from the CCD image sensors 30R to 30B for each color with a predetermined gain, and outputs an image for each color from the amplifier circuit 33R to 33B for each color. It has the high-intensity compression device 1 for performing high-intensity compression processing on data.

In the camera device, the gamma correction circuits 34R to 34B for the respective colors, which perform the gamma correction processing on the image data for the respective colors from the high-intensity compression device 1, respectively.
And white clip circuits 35R to 35 for the respective colors, which cut and output high-frequency components of a predetermined level or higher in the image data for the respective colors from the gamma correction circuits 34R to 34B for the respective colors.
B and the white clip circuits 35R to 35B for the respective colors
A matrix conversion circuit 36 for performing a matrix conversion process on the image data for each color from the above, and an encoder 37 for forming and outputting composite video data based on the image data for each color subjected to the matrix conversion process. ing.

Next, the operation of the high-intensity compression device 1 according to the first embodiment will be described, including the operation of the camera device having such a configuration.

First, in FIG. 2, when the image pickup of a desired subject is started, the CCD image sensors 30R to 30B for the respective colors receive the image pickup light for the respective colors formed from the image pickup light to obtain the image pickup data for the respective colors. Are formed, and these are supplied to the high-intensity compression device 1 through the respective color amplifying circuits 33R to 33B.

The image pickup data for each color supplied to the high-intensity compression device 1 is input terminals 18R to 18 for each color shown in FIG.
The maximum value detection circuit 2 and each color delay circuit 15 through B
17 respectively.

The maximum value detection circuit 2 detects the maximum level of image data from the image data for each color, and converts the maximum value data indicating the level of the image data into the reciprocal conversion circuit 3 and the reference data of the comparator 4. It is supplied to the input terminal 4a.

The reciprocal conversion circuit 3 forms the reciprocal of the maximum value data and supplies it to the multiplier 7.

On the other hand, the high-intensity compression apparatus 1 suppresses the output level by performing compression processing on the image data having an input level equal to or higher than the knee point, which is a predetermined level, as shown in FIG. The knee point data indicating the level of the knee point is supplied through the input terminal 20, and the knee slope data indicating the slope of the high brightness compression processing is supplied through the input terminal 22. The knee point data is supplied to the comparison data input terminal 4b of the comparator 4 and the multiplier 6, and the knee slope data is supplied to the subtractor 5 and the adder 8.

The comparator 4 compares the maximum value data with the knee point data to detect whether the maximum value data is equal to or more than the knee point data. For example, the maximum value data is If it is above the knee point data, high level switching control data is formed. If the maximum value data is below the knee point data, low level switching control data is formed. Changeover switch 12-14
Supply to.

In addition to the knee slope data, the subtractor 5 is supplied with one data indicating the slope when high brightness compression processing is not performed. The subtractor 5 subtracts the knee slope data from the 1 data,
The subtracted data is supplied to the multiplier 5.

The multiplier 5 multiplies the knee point data by the subtraction data, and supplies the multiplication data to the multiplier 7 to which the maximum value data which is the reciprocal is supplied.

The multiplier 7 multiplies the reciprocal maximum value data by the multiplication data from the multiplier 6 and supplies it to the adder 8.

The adder 8 adds the multiplication data from the multiplier 7 and the knee slope data to form high-intensity compressed data for applying high-intensity compression processing to the image data for each color. And supplies them to the respective color multipliers 9-10.

Here, the arithmetic processing performed by the subtractor 5 to the adder 8 to form the high-intensity compressed data is CMP for the high-intensity compressed data, Xmax for the maximum value data, and KS for the knee slope data. When the knee point data is KP, it can be expressed by the following formula.

CMP = [KS.Xmax + KP. (1-KS)] / Xmax = [KP. (1-KS) / Xmax] + KS That is, the maximum value detection circuit 2 causes the C for each color to be changed.
When Xmax (maximum value data) is detected from the image data for each color supplied from the CD image sensors 30R to 30B, this Xmax is converted to the reciprocal by the reciprocal conversion circuit 3 (1 / Xmax). In the multiplier 7, the KP · (1 calculated by the subtracter 5 and the multiplier 6 is calculated.
-KS) and multiplication processing (KP · (1-KS) / Xm
ax). And this KP · (1-KS) / Xmax
However, in the adder 8, the knee point data (K
P) is added to form the high brightness compressed data (CMP) in the above equation.

The delay circuits 15 to 17 for the respective colors delay the delay for the time required for the arithmetic processing performed in the multiplier 11 for the subtractors 5 to R to the input terminals 18R, 18 for the respective colors.
The image pickup data for each color supplied via G and 18B is applied to the selected terminals 12b-1 of the color multipliers 9-11 and the color changeover switches 12-14.
4b, respectively.

The color multipliers 9 to 11 multiply the image pickup data for each color by the high-brightness compressed data supplied from the adder 8 to simultaneously compress the image pickup data for each color with high-brightness. The selected terminals 12 of the color changeover switches 12 to 14 are processed.
a to 14a.

As a result, the high-luminance compression-processed image data for each color is supplied to each selected terminal 12a-14a of each color changeover switch 12-14, and each color changeover switch 12-14 is supplied. Image data for each color that has not been subjected to high-luminance compression processing is supplied to each of the selected terminals 12b to 14b.

As described above, the changeover switches 12 to 14 for the respective colors are supplied with the changeover control data from the comparator 4, and the respective changeover control data are controlled simultaneously. .

Specifically, the respective color changeover switches 12 to 14 detect that the comparator 4 detects image pickup data exceeding the level of the knee point data among the image pickup data, and the comparator 4 outputs a high level. When level switching control data is supplied, the above selection terminals 12c
.. to 14c to select each of the selected terminals 12a to 14a, and output the image data for each color that has been subjected to the high brightness compression processing. Further, the changeover switches 12 to 14 for the respective colors are
In the comparator 4, when the low level switching control data is supplied from the comparator 4 without any of the image pickup data exceeding the level of the knee point data, the selection terminals 12c to 14c are used. The selected terminals 12b to 14b are selected to output the image data for each color that has not been subjected to the high brightness compression process.

The high-luminance compression-processed image data for each color and the high-luminance compression-processed image data for each color selected by the changeover switches 12 to 14 are output terminals for each color. 23R, 23
Gamma correction circuit 3 for each color shown in FIG.
It is supplied to 4R, 34G, and 34B.

As described above, the image pickup data having the highest level is detected from the RGB image pickup data, and when the image pickup data level is equal to or higher than the knee point data level, the image pickup data having the highest level is obtained. At the same time that the high-intensity compression processing is performed on the image pickup data, the high-intensity compression processing performed on the image pickup data is also performed on the other image pickup data, so that each of the RGB input images is input as shown in FIG. High brightness compression processing can be performed while maintaining the data ratio. Therefore, it is possible to reduce the deviation between the hue of the subject at the time of imaging and the hue at the time of display,
Color reproducibility can be improved.

Next, in FIG. 2, the image data for each color supplied to the gamma correction circuits 34R, 34G, 34B for each color is subjected to a predetermined gamma process, and the white clip circuits 35R, 35G, 35B for each color. Is supplied to. White clip circuits 35R, 35 for each color
The white clip levels of G and 35B are respectively set to the maximum output level of the camera device. The white clip circuits 35R, 35G, 35B for each color are
White clip processing is performed to cut the image data for each color that is equal to or higher than the maximum output level, and these are supplied to the matrix circuit 36.

As described above, since the high-luminance compression processing is performed on the image data for each color, the data amount of the image data in the high band between the knee point level and the white clip level should be increased. You can Therefore, even if an image corresponding to the imaged data that has been subjected to the high-intensity compression processing is displayed with a higher brightness level, the image corresponding to the imaged data of the higher band is displayed up to the limit because the amount of data in the higher band is large. It is possible to suppress the color skip phenomenon.

The matrix circuit 36 performs matrix conversion processing on the image data for each color subjected to the white clip processing, and supplies these to the encoder 37.
The encoder 37 forms, for example, composite video data based on the image data for each color, and supplies the composite video data to, for example, a video tape recorder device or a monitor device via an output terminal 38. As described above, since the image pickup data for each color is subjected to high-intensity compression processing while maintaining the ratio at the time of input, image pickup with good color reproducibility in the video tape recorder device or monitor device. Data can be recorded or displayed.

Next, the second embodiment of the high-intensity compression device according to the present invention.
The embodiment will be described.

The high-intensity compression apparatus according to the second embodiment is an independent control type high-intensity for each color that independently applies high-intensity compression processing to the input image data for each color of RGB as shown in FIG. The compression circuits 41R, 41G, and 41B, the high-intensity compression device 1 that performs the above-described high-intensity compression processing on the input image data for each color, and the independent-control-type high-intensity compression circuits 41R, 41G, and 41B for each color, respectively Each color image pickup data subjected to the luminance compression process and each color image addition data subjected to the high luminance compression process by the high-luminance compression device 1 are added by respective color adders 42 to 44.

The high-intensity compressing device according to the second embodiment having such a structure has input terminals 40R, 40G, 40B.
Through the CCD image sensors 30R, 3 for each color
Image pickup data for each color from 0G and 30B is supplied, and these are independently controlled high brightness compression circuits 41R,
It is supplied to 41G and 41B, respectively, and is also supplied to the high-intensity compression device 1.

Independent control type high brightness compression circuit 41 for each color
Each of the R, 41G, and 41B has the configuration shown in FIG. 6, and the imaging data is selected by the reference data input terminal 53a of the comparator 53, the subtractor 54, and the changeover switch 57 via the input terminal 50. It is supplied to each terminal 57a.

The comparison data input terminal 53 of the comparator 53.
The knee point data of a predetermined level is supplied to b through the input terminal 51. The comparator 53 compares the level of the image pickup data with the level of the knee point data. For example, when the level of the image pickup data is equal to or higher than the level of the knee point data, the high level switching control data is switched to the changeover switch 57. When the level of the imaging data is equal to or lower than the level of the knee point data, the low level switching control data is supplied to the changeover switch 57.

The knee point data (KP) supplied through the input terminal 51 is added by the subtractor 54 to which the image pickup data (x) is supplied and the multiplication data from the multiplier 55 described later. Respectively to the vessels 56. Further, the input terminal 52 is supplied with knee slope data for performing high brightness compression processing. This knee slope data is supplied to the multiplier 55.

The subtractor 54 subtracts the knee point data from the imaged data and supplies the subtracted data (x-KP) to the multiplier 55.

The multiplier 55 outputs the subtracted data (x-
KP) is multiplied by the knee slope data (KS), and the multiplied data (KS × x−KS × KP) is supplied to the adder 56 to which the knee point data (KP) is supplied.

The adder 56 outputs the multiplication data (KS
(× x−KS × KP) and knee point data (KP) are added to form image pickup data (KS × x−KS × KP + KP) that has been subjected to high-intensity compression processing, and this switch 57 is used. Of the selected terminal 57b.

As described above, the changeover switch 57 is used.
Is supplied with the switching control data from the comparator 53. When the high-level switching control data indicating that the level of the input imaging data is equal to or higher than the knee point data level is supplied from the comparator 53, the changeover switch 57 selects the selected terminal 57b by the selection terminal 57c. Is selected to output the image pickup data subjected to the high-intensity compression processing. Further, when the changeover switch 57 is supplied with low level changeover control data indicating that the level of the inputted image pickup data is equal to or lower than the level of the knee point data, from the comparator 53,
The selected terminal 57a is selected by the selection terminal 57c, and the input imaging data is output as it is.

Independent control type high brightness compression circuit 41 for each color
In this way, the R, 41G, and 41B separately perform high-intensity compression processing on the above-mentioned image data for each color,
These are supplied to the respective color adders 42 to 44 shown in FIG. 5 through the output terminal 58.

By performing different high-intensity compression processing on the image data for each color in this way, the high band ratio is input to each of the color adders 42 to 44 as shown in FIG. The image pickup data for each color, which is changed with respect to the ratio, is supplied.

On the other hand, as described in the first embodiment, the high-intensity compression apparatus 1 detects the highest-level image pickup data from the input image pickup data for each color, and the level of this image pickup data is When the level is equal to or higher than the knee point data level, the high-intensity compression process is performed on the image data having the highest level, and at the same time, the high-intensity compression process performed on the image data is performed on the other image data. By doing so, as shown in FIG. 4, the high-luminance compression processing is performed while maintaining the ratio at the time of input to form the image data for each color, and these are supplied to the color adders 42 to 44.

The adders 42 to 44 for the respective colors are the image pickup data for the respective colors which have been individually subjected to the high-brightness compression processing in the independently controlled high-brightness compression circuits 41R, 41G and 41B for the respective colors, and the high-brightness. In the compression device 1, the high-luminance compression processing is performed while keeping the ratio at the time of input, and the addition processing is performed on each of the color-imaging image data, and the addition processing is performed through the output terminals 45R, 45G, 45B for each color to the above-mentioned FIG. The signals are supplied to the gamma correction circuits 34R, 34G, 34B for each color shown.

As described above, the RGB high-luminance compression is performed simultaneously by performing the addition processing of the high-luminance compression processing for each RGB, and the respective color image data subjected to the high-luminance compression simultaneously for RGB. It is possible to prevent the inconvenience that the display image is over-colored when the processing is performed, and it is possible to perform the high-luminance compression processing that provides a more natural display image.

In the second embodiment, the high-intensity compression processing for each color and the RGB high-intensity compression processing for which the high-intensity compression processing is separately performed for each of the RGB, which is added in the respective color adders 42 to 44, are performed. It is also possible to variably control the addition ratio of the image data for each color that has been subjected to. In this case, a desired high-luminance compression process can be performed, and convenience can be improved.

Finally, in the above description of the respective embodiments, the high-intensity compression apparatus 1 performs high-intensity compression processing by digitally processing the imaged data. Alternatively, the high brightness compression process may be performed.

Further, the high-intensity compression device according to the present invention is applied to a three-plate type camera device. However, the high-intensity compression device is not limited to this, for example, in three primary colors such as a video camera device. The invention can be applied to any device that handles image information, and in addition, various modifications can be made without departing from the technical idea of the present invention.

[0068]

As described above, the high-intensity compression apparatus according to the present invention simultaneously applies high-intensity compression processing to the image information of the three primary colors, so that the high-intensity image is retained while maintaining the ratio of the image information of the three primary colors at the time of input. A compression process can be performed. Therefore, it is possible to reduce the deviation between the hue of the subject at the time of image capturing and the hue at the time of displaying, and it is possible to improve the color reproducibility.

Further, in the high-intensity compression apparatus according to the present invention, the high-intensity compression processing is performed simultaneously by the high-intensity compression section and the image information that has been individually subjected to the high-intensity compression processing. By performing addition processing with each of the image information, it is possible to prevent the inconvenience that the displayed image is over-colored, which occurs when the high-intensity compression processing is performed on each of the above-mentioned image information at the same time. It is possible to perform high-intensity compression processing that provides a different display image.

[Brief description of drawings]

FIG. 1 is a block diagram of a high-intensity compression device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a three-plate type camera device provided with the high-intensity compression device according to the first embodiment.

FIG. 3 is a diagram showing knee points and knee slopes of high-intensity compression processing performed in the high-intensity compression apparatus according to the first embodiment.

FIG. 4 is a diagram showing RGB image pickup data subjected to high-luminance compression processing in the high-luminance compression apparatus according to the first embodiment.

FIG. 5 is a block diagram of a high-intensity compression device according to a second embodiment of the present invention.

FIG. 6 is a block diagram of an independent control type high brightness compression circuit provided in the high brightness compression apparatus according to the second embodiment.

FIG. 7 is a diagram showing RGB image pickup data subjected to high-luminance compression processing in the independent control type high-luminance compression circuit.

[Explanation of symbols]

1 High-intensity compression device 2 Maximum value detection circuit 3 Reciprocal number conversion circuit 4 Comparator 5 Subtractor 6,7 Multiplier 8 Adder 9-11 Multiplier for each color of RGB 12-14 Changeover switch 15-17 Delay circuit 18R-18B Input terminal for image data for each color of RGB 20 Input terminal for knee point data 21 Input terminal for data 22 Input terminal for knee slope data 23R to 23B Output terminal for image data for each color of RGB 41R to 41B Independent control for each color of RGB Type high-intensity compression circuit 42-44 RGB adder for each color

Claims (2)

[Claims] 1. A maximum level detecting means for detecting maximum level image information from image information of three primary colors supplied from the outside, a level of image information detected by the maximum level detecting means, and a high brightness. The high-intensity compression levels indicating the levels of the image information to be compressed are compared, and when the level of the image information is higher than the high-intensity compression level, the predetermined high-intensity compression is performed simultaneously on the image information of the three primary colors. A high-intensity compression device having high-intensity compression means for performing processing. 2. A high-intensity compression unit that individually performs a predetermined high-intensity compression process on each of the image information that exceeds the high-intensity compression level, and a high-intensity compression unit that separately performs high-intensity compression. 2. An addition means for adding each processed image information and each image information subjected to the high-intensity compression processing by the high-intensity compression means at the same time and outputting the result. High brightness compression device.