JPS5871786A - Processor of image pickup signal - Google Patents

Abstract

PURPOSE:To increase the degree of freedom for compensation of colors, by having the control of white balance and the compensation of colors which are independent of each other. CONSTITUTION:The memories 20 and 30 consists of RAMs respectively, and various types of compensation data are previously written into these memories for three primary color signals R, G and B and a luminance signal Y which are calculated by a CPU40. The three primary color compensating signals DELTAR, DELTAG and DELTAB which are read out of the memory 20 are converted into a color difference type by a matrix circuit 21 and then supplied to a signal synthesizer 24 via multipliers 22 and 23 to be converted into a color compensating signal DELTAC. The white balance control signals DELTARw, DELTAGw and DELTABw of three primary color signals which are read out of the memory 30 are converted into a color difference type by a matrix circuit 31 and supplied to color signal adders 32 and 33 for detection of white balance. At the same time, these white balance control signals are converted into the white balance control signals DELTAUw and DELTAVw corresponding to color signals U and V through adders 34 and 35 and then supplied to the synthesizer 24 via a signal selecting circuit 38 which is controlled by a white color signal detecting circuit 36.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal processing device for image signals obtained by a color television imaging device, and more particularly to a signal processing device capable of independently performing white balance adjustment and color correction.

Generally, in a television system, a video signal captured by an imaging device is converted into an NTS C (National Te...
levision System Comm1ttee
) system and other standard television systems, converts it into a composite color television signal compatible with a composite color television system, transmits it, receives the television signal with a television receiver, and reproduces the image. There is. In order to reproduce faithful images in such television systems, it is necessary to adjust the white balance of the three primary color signals obtained by the imaging device, and perform gamma correction on the imaging side, which reversely corrects the gamma characteristics on the receiving side. It is necessary to perform various signal processing on the video signal on the imaging side, such as color temperature correction for the color temperature of the illumination at the time of imaging.

The various types of signal processing described above have conventionally been performed by controlling the response characteristics of preamplifiers, process amplifiers, etc. installed in imaging devices, and white balance adjustment and color correction are related to each other. Because the signal was processed
In particular, the degree of freedom in color correction is limited, and it has not been possible to perform sufficient signal processing in accordance with actual imaging conditions.

The present invention includes a data table in which white balance adjustment data is written in advance in a first memory, and a data table in which color correction and New Year's data are written in advance in a second memory. There is a method to provide a signal processing device with a novel configuration in which white balance adjustment and color correction can be performed independently by using the present invention, thereby increasing the degree of freedom in color correction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing one embodiment.

In the embodiment shown in FIG.
After being digitized by an A/D converter 1, the color signal C is separated by a bandpass filter 11, and the color signal C is subtracted and synthesized by a signal adder 2, thereby producing a luminance signal Y. are separated, and the color signal C and the luminance signal Y
The correction data ΔCP formed based on is added and synthesized by the signal adder 8 on the output side to perform correction,
Output terminal 1 via digital/analog D/A converter 9
Output from θ.

The color signal C separated by the bandpass filter 11 is separated into a U color signal and a U color signal by a signal separation circuit 131. The above U color signal is supplied to the first multiplier 15 via the first frequency interpolation filter 14, and is given a predetermined weight (X2.03) by the multiplier 15, so that the blue primary color difference B- It is converted into a Y signal. Further, the U color signal is supplied to a second multiplier 17 via a second frequency interpolation filter 16, and is converted into a red primary color difference RY signal by the multiplier 17. The above Y signal, B-Y signal and l't
-Y signal is supplied to the first IJ circuit 18,
The three primary color R and 6°B signals are obtained from the IJ circuit 18. The R signal obtained by the matrix circuit 18, the G signal
The B signal is used as a readout address signal for each of the first memory 20 in which the color correction data table is written and the second memory 30 in which the white balance adjustment data table is written. Further, the Y signal is used as a read address signal for the color correction data table written in the first memory 20.

Here, each of the memories 20 and 30 is constituted by, for example, a random access memory, and receives the three primary color R10°B signals and the luminance Y which are calculated by the microprocessor 40.
Various correction data regarding signals are written in advance.

Three primary color correction signals Δ read out from the first memory 20
R9ΔG and ΔB are converted into color difference formation in the second matrix circuit 21, and then converted into the third. After being weighted by fourth multipliers 22 and 23, it is converted into a color correction signal ΔC by a signal combiner 24. This color correction signal ΔC is sent to the first memory 2.
The signal adder 25 adds and synthesizes the brightness correction signal ΔY read out from 0, and supplies the resultant signal to the signal adder 8 on the output side as correction data ΔCP.

Further, the white balance adjustment signals ΔRW, ΔGw, 68w of the three primary color signals read from the second memory 30 are processed in the matrix circuit 31 in color difference formats Δ(B-Y)w, Δ
(RY)w is supplied to each signal adder 32.33 for white balance detection, and is weighted by each multiplier 34.35 to correspond to a U color signal and a V color signal. White balance adjustment signals △Uw, ΔvW
and is supplied to the signal synthesizer 24 via the signal selection circuit 38. Each of the signal adders 32 and 33 for detecting the white signal adds each adjustment signal Δ(B-Y)w to each of the color difference B-Y and R-Y signals formed from the input imaging signal.
, Δ(RY)w are added and combined, and the signals are supplied to the white signal detection circuit 36. This white signal detection circuit 36 always determines the presence or absence of a white signal with respect to the input imaging signal, and when the white signal is stored, activates the signal selection circuit 38 to select each white balance adjustment signal ΔUw, ΔVw. The signal is supplied to a signal combiner 24.

For example, in the case of an NTSC standard color television signal, the white signal detection circuit 36 uses the following equation: RY+0.7△Rw-0.1lB=O". ΔRw+0.898=O...The white signal can be detected by determining whether or not the second equation, the first equation and the second equation, are simultaneously satisfied. Also, instead of the first and second equations above, (,RY)-(B-Y)+△Rw-ΔBw=0...
A white signal can also be detected by determining whether or not the third equation is satisfied.

In the embodiment configured as described above, the color correction process based on the color correction data table written in the first memory 20 and the white balance adjustment process written in the second memory 30 are performed by a signal. It can be selected by the selection circuit 38 and independently applied to the input imaging signal. The operation of the signal selection circuit 3B is controlled by a white signal detection circuit 36, and when the input imaging signal is a white signal, that is, when white balance adjustment is required, the signal selection circuit 3B is automatically switched to the white balance adjustment state. Therefore, arbitrary color correction can be performed while maintaining white balance.

As is clear from the above description of the embodiments, according to the present invention, a first memory in which a color correction data table is written and a second memory in which a white balance adjustment data table is written. a memory, a six-color signal detection circuit that determines whether or not the signal corrected based on the white balance adjustment data read from the second memory using the signal level of the input imaging signal as an address is a white signal; The signal selection circuit is equipped with a signal selection circuit whose operation is controlled by the detection output from the white signal detection circuit, and the signal selection circuit selects the data read out from each memory using the signal level of the input imaging signal as an address, and selects the selected data. The present invention is characterized in that the input imaging signal is subjected to signal processing based on the above input image signal and outputted, thereby making it possible to perform color correction processing and white balance adjustment independently, and performing color correction processing with a high degree of freedom. and can fully achieve the intended purpose.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a signal processing circuit according to the present invention. 1...-A/D converter 8.12, 25, 32.33...Signal adder 9...
・・・・・・・・・・・・D/A converter 10...
・・・・・・・・・・・・Signal output terminals 20, 30
・・・・・・Memory 36・・・・・・・・・・・・・White signal detection circuit patent applicant Sony Corporation representative Patent attorney Kodo Koike 1) Sakae Mura −

Claims (1)

[Claims] a first memory in which a color correction data table is written;
A white signal is a signal corrected based on a second memory in which a white balance adjustment data table is written and white balance adjustment data read from the second memory using the signal level of the input imaging signal as an address. It is equipped with a white signal detection circuit that determines whether or not the white signal is detected, and a signal selection circuit whose operation is controlled by the detection output from the white signal detection circuit. Selected by the signal selection circuit above, and signal processing based on the selected data.