JPS60144092A - Color matching device of video camera - Google Patents

Abstract

PURPOSE:To attain color matching while taking notice of an optional hue and to guarantee the continuity of color by rewriting a lookup data for color correction written in a memory means provided to a video camera to be adjusted at a correction control means. CONSTITUTION:Color difference signals UA', VV' outputted from a color correction circuit 10 of the video camera 100 to be adjusted are applied to a chromaticity correction controller 110. Further, reference color difference signals UB, VB formed by an image pickup output by a reference video camera are applied to the chromaticity correction controller 110. The chrominance correction controller 110 calculates correction amounts DELTAU, DELTAV according to Equation I by using sampled color difference signals UAS, VAS, UBS, VBS to generate a lookup table data converting the U, V to U+DELTAV and V+DELTAV. The lookup data formed by the chromaticity correction controller 110 is applied to a microprocessor 20 of the video camera 100 to be adjusted and given to a color correction circuit 10. The video camera 100 to be adjusted applies color correcting processing based on the lookup data formed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera color matching device for matching color reproducibility when a common subject is imaged by a plurality of video cameras.

[Background technology and its problems]

In general, when images of a common subject are captured by multiple video cameras, if the color reproducibility of each video camera is not 7i, the color reproducibility will be affected when switching or combining images from each video camera. The error is noticeable and extremely inconvenient.

It has long been known that the color reproducibility of video cameras is affected by the characteristics of the imaging optical system, image sensor, or signal processing system, and color reproduction errors caused by the optical system are affected by so-called color reproduction errors in the signal processing system. It was corrected by masking processing.

Generally, in signal processing for color correction, each color signal R, G
, B, by adding the correction amounts Δr, Δg, and Δb of each color as shown in the following, the color signals R, G, and B of the correction amount are formed. And each correction amount Δr, Δg.

△b is the color difference signal RG, G obtained by the matrix calculation shown in the second formula.
-J3. Calculated from BR.

In this way, if each correction signal △r, △g, △b is formed based on each color difference signal 1%-G, GB-B, BR, the white balance of the valley-corrected color signals JG, B can be maintained. color correction processing.

Conventionally, in color correction processing, the imaging output is treated as an analog signal, and the calculations of the first and second equations are performed using a color correction circuit that combines an analog signal synthesizer, weighting circuit, etc. It was held at

By the way, in the conventional color correction circuit using analog signal processing, Masaki Tanisode Δr, Δg, Δl) given by the matrix calculation of the above second equation is If the matrix constant [ai+] is changed, hues other than the above-mentioned target hue are affected, so the above-mentioned matrix constant [ai+] is arbitrarily set to selectively correct only the target hue. It was extremely difficult.

When performing color correction focusing on an arbitrary hue S to match the color of a video camera, in order to guarantee color continuity, colors in the vicinity of the focused hue S should also be corrected in the same way.
Further, it is necessary to keep colors of the same hue the same even after correction, and furthermore, it is necessary to make the absolute value of the correction amount smaller as the distance from the hue 571) increases.

OBJECTS OF THE INVENTION] Therefore, the present invention provides a color matching device with a novel configuration that performs color matching by focusing on arbitrary hues and can guarantee color continuity.

[Summary of the invention]

In order to achieve the above-mentioned object, the color matching device for a video camera according to the present invention includes a memory means from which color correction rendering color difference signal data is read out using the actual color difference signal data formed based on the imaging output as a readout address. The correction control means, which is provided in the video camera to be adjusted and creates lookup data for color correction from the reference color difference signal data and the actual color difference signal data, writes the lookup data in the memory means, and The present invention is characterized in that the hue of the adjustment video camera is made to match the reference hue given by the reference color difference signal data.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In the embodiment shown in the block diagram of FIG. 1, the video camera 100 to be adjusted handles the luminance signal YA1 color difference signal [JA, VA, which is formed based on the image pickup output thereof, as a technology take, and the color difference signal UA, V
A color correction circuit 10 using a look-up table for color correction that uses A as a read address data; a microprocessor 20 that controls the operation of this color correction circuit 10;
The apparatus includes an encoder 30 for synthesizing the color-corrected color difference signals UA and VA read out from the color correction circuit 10 and the NTSC color television signal SNTSC based on the luminance signal Yh.

The color correction circuit 1 of the video camera 10u to be adjusted is
The color difference signals OA and VA output from 0 are supplied to a chromaticity correction controller 110. In addition, the encoder 30
NTSC color television signal SNT
The SC is supplied to a motor television receiver 120.

The chromaticity correction controller 110 is supplied with reference color difference signals UB and Vn formed by image pickup output from a reference video camera (not shown).

The video camera 100 to be adjusted and the reference video camera both capture images of a reference subject.

Further, the chromaticity correction controller 1'10 supplies a cursor signal specifying an arbitrary hue S in the reference subject to the monitor television receiver 120, and the chromaticity correction controller 1'10 supplies the monitor television receiver 120 with a cursor signal specifying an arbitrary hue S in the reference object, and Each color difference signal UA, VA, UB obtained by the video camera to be adjusted 100 and the reference video camera.

Va is sampled. Note that sampling of each of the color difference signals 'VA, UB, and VB is performed with the video camera 100 to be adjusted in an unadjusted state.

Here, the correction amounts ΔYS, ΔUs,
ΔVs is given by: Further, an arbitrary chromaticity signal C is U.

■I for each unit vector of the U-axis and V-axis of the coordinates.

y is expressed as U -ut+V .7==C-exp jθ, aQE, and can be expressed in polar coordinates as shown in FIG.

Then, the specific hue S is set while ensuring color continuity.
To perform the color correction, the correction amount is given within the area Dc which is the three-dimensional area to be corrected for the hue S projected onto the U and V coordinates, and the correction amount is set to 0 outside the area Dc, and the correction amount is set to 0 outside the area Dc. The correction amount may be given by a continuous function within the region Dc and on its boundaries θl, 02. For a practical correction area Dc, as shown in FIG. 3, the same hue may be set as a boundary 01<θ<02.

Also, the hue U of the signal after correction with respect to the hue θA before correction
In order to ensure the monotonicity of A+Δθ, as shown in FIG. 4, it is sufficient to set θ1×vAS+θBS<θ2 as a boundary.

Therefore, the amount of correction for any chromaticity signal is ΔC=ΔU−
As w+△■・V, △U−au(−
UA--01+VA)" ・(-UA-1θ2+
V A )n'△V=av ([JA-tan01+V
person) m -(-UA °1a02+V person)'...
...The fourth equation is given. Here, the above au.

av is au=(U
ns-[JAs)/(-UAs-1σ1 +VA s
)'.

(-UAS+-θ2+VAs-')" av-(VBs-vAS)/(-UAs-1θl+VA
s )” ・(-EJh 3-1aJI02+VAS)
”.

Then, in the chromaticity correction controller 110, the sampled color difference signals UAS+VAS, Ut+s,
t correction amount △U, Δ according to the above-mentioned 4th formula using VBS
V is calculated and a lookup table data number is created to convert U and V into U + ΔU and 'V + ΔV. The lookup data created by this chromaticity correction controller 110 is supplied to the microprocessor 20 of the video camera 100 to be adjusted, and is applied to the color correction circuit 10. - In the video camera 100 to be adjusted, by performing color correction processing based on the lookup data created as described above, it is possible to capture an image whose color reproducibility matches that of the standard video camera.

FIG. 5 is a block circuit diagram of a specific example of the configuration of the color correction circuit 10 in the above embodiment.

The color correction circuit 10 in this embodiment performs row address selection (RAS: r(ow Address 5tro
be ) function, column address selection (CAS: Col
um Address 5trobe) functions and writing/
Read control (WE: Write Enable)
Two random access memories (RAM) with
: Random Access Memory) 1
1r12 as a look-up table, and the color difference signals OA and VB are supplied to its pair of input terminals 1 and 2.

Further, this color correction circuit 10 is connected to R from the above-mentioned microprocessor 20 via an address bus and a data bus.
Necessary control signals are supplied to the AM controller 4.

The RAM controller 4 outputs a write/read control signal SWE and a row address selection control signal S nAs based on control signals supplied from the microprocessor 20.
, column address control signal S CAS is formed, and each of the above R
The write data supplied to each data input terminal DIN from the microprocessor 20 through the first latch circuit 5 and the data bus is written into the AMI 1.12. The above microprocessor 20
As described above, the look-up table data given by the chromaticity correction controller 110 is supplied to the data input terminals DIN of each of the RAMs 11 and 12 as pledge data. The write address data of the data is input from the microprocessor 20 via the second latch circuit 6 to the input multiplexer 31.
is supplied via this input multiplexer 3 to the above /
41LA'M11, is applied to the 12th valley address take input terminal ADl(,).

Here, the input multiplexer 3 is connected to the input/read control signal Sw generated by the RAM controller 4.
It consists of an input selection switch circuit 3A whose switching is controlled by 1.B, and an output selection switch circuit 3B whose switching is controlled by an input multiplexing clock ζ provided by a clock generator (not shown). The write address data is supplied to each RAM 11.12 during a period in which the AM controller 4 controls each of the RAMs 11 and -112 to read operation state.

Further, the input multiplexer 3 is supplied with color difference signals Ua, . . . VA from the pair of input terminals 1 and 2.
1.12 is controlled to the read operation state, during the period,
The color difference signals OA and VA are read and supplied as read address data to the address data input terminals AD of the RAMIs 1 and 12, respectively.

The color difference signals UA and VA are read out from each I(AMI'1 and 12) using the color difference signals UA and VA as read address data, and the color difference signals UA and VA are outputted from a pair of output terminals 13 and 14.

Like this color correction circuit 10, a pair of color difference signals UA, V
By reading out the color correction source take from AM using A as the read address, the necessary color correction can be performed using a two-dimensional lookup table.

Further, the lookup table data for color correction written in the above R and AM is created by digital processing by the chromaticity correction controller 110 provided outside the video camera 100 to be adjusted. It is also possible to easily perform non-linear color masking processing to selectively correct the difference.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, in the color matching device for a video camera according to the present invention, the lookup data for color correction written in the memory means provided in the video camera to be adjusted is controlled by the correction control means. Color matching can be done with a simple operation of rewriting. Further, 11. used as the above memory means. Since AM and the like can handle a large amount of digital information, lookup data for performing non-linear color masking processing can be created by the correction control means and stored in the memory means, so that it can be applied to any hue. It is also possible to selectively match colors.

Therefore, according to the present invention, the intended purpose can be fully achieved.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a color matching device for a video camera according to the present invention. FIGS. 2, 3, and 4 are diagrams explaining the operating principle for selectively matching arbitrary hues in the above embodiment, and FIG. U, V
FIG. 3 is a vector diagram showing a correction area for color correction for a specific hue, and FIG. 4 is a characteristic diagram showing the monotony of the hue of the signal after correction. FIG. 5 is a block circuit diagram showing a specific example of the configuration of the color correction circuit used in the above embodiment. 10・・・・・・・・・・・・Color correction circuit 11.
12. River...RAM 20......Microprocessor 30...Encoder 10
0...... Video camera to be adjusted 11
0・・・・・・・・・Patent applicant for chromaticity correction control Patent attorney for Sony Corporation Kodo Koike 1) Sakae Mura − 2″′ 4th degree 3rd m θ2

Claims (1)

[Claims] The video camera to be adjusted is provided with a memory means from which the color correction amount color difference signal data is read out using the actual color difference signal data formed based on the image pickup output as a read address, and the reference color difference signal data and the actual color difference signal data are read out. A correction control means for creating lookup data for color correction from the above, writes the lookup data in the memory means, and matches the hue of the video camera to be adjusted with the reference hue given by the reference color difference signal data. A color matching device for a video camera, characterized in that: