JPS63286087A - Color adjusting circuit - Google Patents

Abstract

PURPOSE:To adjust color reproducibility simply and accurately by using a microcomputer so as to vary the ratio of addition/subtraction in a way that an output of a signal processing circuit or an arithmetic processing circuit becomes a prescribed value when each optical information of an optical prism separating a light beam into the three primary colors is converted into an electric signal by an image pickup element to pick up an object. CONSTITUTION:Each signal level, in the correct color reproducing state of R, G, B signals obtained in picking up a standard object, is stored in advance in a microcomputer 26. Then the standard subject 1 is picked up by an actual television camera and an operation start switch 34 operates the computer 26. The computer 26 calculates from the difference between the normal level storing the R, G, B signals corresponding to a red mark at, e.g., a 1/3 to the left of the subject and the level obtained actually to calculate the signal level of G-R to be added to the signal G and the signal level of B-R to be added to the signal B to control the gain of gain controllers 28, 30. Thus, the output of adders 12, 13, 14 reaches the normal color reproducing state simply and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides optical prisms for capturing optical information of an object.
The present invention relates to a color adjustment circuit for a television camera that separates colors into primary colors, converts the color-separated optical information into an electrical signal using an image sensor, and processes the electrical signal to obtain a television signal.

Conventional technology A television camera bar that uses three image sensors.

It is generally used for broadcasting purposes, and its specifications are strict. In particular, the requirements for color reproducibility are strict, and this is because broadcasting stations often broadcast while switching between multiple television cameras, and in this case, the difference in color reproducibility is a relative comparison between each television camera. This is because it becomes more noticeable.

Factors that cause changes in color reproducibility include variations in the spectral sensitivity characteristics of lenses, optical prisms, and image sensors. It is impossible to suppress these variations to a level that satisfies the requirements.

In reality, differences in color reproducibility are matched through adjustment. FIG. 4 shows a block diagram of a color adjustment circuit that adjusts this color reproducibility. 1 is the optical lens, 2 is the optical information of the subject incident through the optical lens, red (6), green ◎, blue (B
), 3 and 4.5 are image pickup devices that convert the color-separated optical information of the subject into electrical signals, and 6° and 7.8 are image pickup devices 3, 4.8, respectively.
A pre-processing circuit performs processing such as amplifying the output signal of 5 to an appropriate level, and 9 is a B signal obtained from the image pickup devices 6 and 7.

M mixes G signal and creates R-G signal and G-B signal
IX circuit, 1o is the B signal obtained from the image sensors 6 and 8,
MI that mixes the B signal and creates R-B signal and B-B signal
X circuit, 11 is G signal obtained from image sensor 7 and 8, B
MIX mixes signals and creates G-B signal and B-G signal
18 is a variable resistor that adjusts the level of the G-B signal created by the MIX circuit 9; 19 is a variable resistor that adjusts the level of the R-G signal created by the MIX circuit 9; 20 is an M
A variable resistor 21 adjusts the level of the B-B signal created by the IX circuit 10, a variable resistor 21 adjusts the level of the R-B signal created by the MIX circuit 1o, and 22 a variable resistor that adjusts the level of the R-B signal created by the MIX circuit 1o.
A variable resistor 23 adjusts the level of the G-B signal generated by the MIX circuit 11, a variable resistor 12 adjusts the level of the G-B signal generated by the MIX circuit 11, and a variable resistor 12 adjusts the level of the G-B signal generated by the MIX circuit 11. An adder 13 adds the level-adjusted R-G signal and R-B signal; 13 is an adder that adds the level-adjusted G-B signal and the G-B signal; 14;
is the output signal of the preprocessing circuit 8 and the level-adjusted B-G.
adders 17, 18' for adding signals, B-B signals;

19 is a post-processing circuit that performs processing such as gamma correction on the output signals of the adders 12, 13, and 14, respectively; and 24 is a drive circuit that drives the image sensor.

The operation of the conventional color processing circuit configured as described above will be explained.

The optical information of the subject is separated into three primary colors by the prism 2 and converted into electrical signals by the image sensors 3, 4, and 5. Prism 2, image sensor 3, 4,
Differences in spectral sensitivity characteristics, etc. of No. 5 cause deviations in color reproducibility. For example, the output signal of the preprocessing circuit 9 (B
signal), the R-G signal created by MIX circuit 9 and MIX
The correction is made by adding the R-B signals generated by the circuit 1° at an appropriate level.

Problems to be Solved by the Invention However, the above configuration has the following problems.

Actual correction is performed by taking an image of a suitable subject and adjusting it with variable resistors 19 and 21 while watching the monitor TV so that the levels of the R-G signal and R-B signal to be added to the B signal are optimal. This will be done.

However, perfect color reproducibility cannot be obtained unless all three signals, the B signal, the G signal, and the B signal, are adjusted, and a total of six variable resistors must be adjusted. Moreover, the color reproducibility affects each other, and adjustment is quite difficult.In fact, when a plurality of television cameras are installed, it is impossible to make perfect adjustments.

The present invention has been made in view of the above, and an object of the present invention is to provide a color adjustment circuit that can easily and accurately adjust color reproducibility.

Means for Solving the Problems The color adjustment circuit of the present invention includes an optical prism that separates optical information of a subject obtained through an optical lens into three primary colors of red, blue, and green light; An image sensor that converts optical information into an electrical signal, a signal processing circuit that processes output signals of the image sensor, an arithmetic processing circuit that adds and subtracts each output signal of the signal processing circuit at a constant ratio, and a predetermined subject. The present invention is characterized by comprising circuit means for changing the addition/subtraction ratio by a microcomputer so that the output signal of the signal processing circuit or the arithmetic processing circuit becomes a predetermined value when the image is captured.

Effects of the Invention The present invention has the above-described configuration, and the addition/subtraction ratio is changed by a microcomputer so that the output of the signal processing circuit or the arithmetic processing circuit becomes a predetermined value when a predetermined object is imaged, so that it can be easily and accurately performed. Color reproducibility can be adjusted.

Embodiment FIG. 1 shows a block diagram of a color adjustment circuit in a first embodiment of the present invention. 25 is an A/D converter that converts the preprocessed R signal, G signal, and B signal into digital signals; 26 is an A/D converter that detects deviations in color reproducibility from the R signal, G signal, and B signal converted to digital signals. However, in order to correct this, for example, the R-G signal and R-
Calculate the optimum level of the B signal and use the gain control circuit 28.29
゜A microcomputer that controls the gain of 30, 31, 32, and 33, and 27 a D that converts the control signal of the gain control circuit outputted by the microcomputer 26 into an analog signal.
/A converter, 2B, 29, 30.

31, 32, and 33 are gain control circuits that adjust the signals' outputted from the MIX circuits 9, 1o, and 11 to appropriate levels under control from the microcomputer, and 34 is an operation start switch for the microcomputer.

The operation of this embodiment configured as above will be explained.

Now, suppose that the object shown in Fig. 2A is a standard object, and the correct color reproduction state of the R signal, G signal, and B signal as shown in Fig. 2B, C, and D obtained when this is imaged. Each signal level is stored in the microcomputer 26 in advance. Next, when the standard subject 1 is imaged with an actual television camera and the microcomputer 26 is operated by the operation start switch 34, the microcomputer 2e receives an R signal corresponding to, for example, the red part of the left 1/3 of the subject. Based on the difference between the stored normal levels of the G and B signals and the actually obtained levels, the signal level of GH is added to the G signal, and the signal level of B- is added to the B signal.
Calculate the R signal level and control the gain of the gain controller 28.30. Similarly, the gain controllers 29 and 32 are controlled from the green part in the center 1/3 of the object, and the gain controllers 31 and 33 are controlled from the blue part in the left 1/3. Adder 12゜1
The output of 3.14 is easily and accurately reproduced in normal color.

As described above, according to this embodiment, the regular signal level obtained when a specific subject is imaged is stored in the microcomputer in advance, and from this and each signal level when this subject is actually imaged, By determining the amount of correction, color reproduction can be easily and accurately adjusted.

FIG. 3 shows a block diagram of a color adjustment circuit in a second embodiment of the present invention. This embodiment is almost the same as the first embodiment, but the microcomputer 26
Adders 12, 13, and 14 detect signals, G signals, and B signals.
What happens after is different.

This embodiment configured as described above operates almost the same as the first embodiment, but by configuring it in this way, the entire color adjustment circuit is not a closed loop, and color reproducibility due to variations in the circuit system is reduced. Most of the deviations can be corrected. Therefore, almost the same effect can be obtained even if the R signal, G signal, and B signal are detected immediately before the post-processing circuit 16, 16, and 17.

As described above, according to this embodiment, variations in the circuit system can also be corrected by changing the detection method of the R signal, G signal, and B signal and making the entire color adjustment circuit closed loop. .

In addition, 1. In the second embodiment, the operation was explained by storing regular color reproduction information in the microcomputer.
Color reproducibility becomes a particular problem when a relative comparison is made between multiple television cameras. Therefore, in this case 1. For example, if the color reproducibility of a certain television camera is used as a reference,
If a microcomputer is operated as a reference for other television cameras at each signal level when imaging a specific subject as shown in Figure 2, the relative differences will be eliminated and color reproducibility will be achieved without any practical problems. can get. Further, in this case, it is not necessary for each television camera to have the microcomputer 26, and if there is one in common for the television cameras to be switched, the microcomputer 26 can control the entire system.

Furthermore, although each embodiment has been described using a television camera that processes the output signal of an image sensor as an example, similar effects can be obtained in a television camera that converts the output signal into a digital signal and processes it digitally. Needless to say, it will be.

In this case, A/D converter 25 can be removed.

Further, the present invention relates to an R signal for adjusting color reproducibility.

It goes without saying that the calculation methods for the G signal and B signal are different from those shown in the embodiment, and the same effect can be obtained even if other methods are used.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, color reproducibility can be easily and accurately adjusted by a microcomputer by imaging a predetermined subject.

Its practical effects are great.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a color adjustment circuit according to a first embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same embodiment, and FIG. 3 is a block diagram of a color adjustment circuit according to a second embodiment of the present invention. figure,
FIG. 4 is a block diagram of a conventional color adjustment circuit. 1...lens, 2...prism, 3,
4.5...Image sensor, 9,10.11...
...MIX circuit, 12゜13.14...adder, 26...A/D converter. 26...Microcomputer, 2nd...
...D/A converter, 28-31...gain controller. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure (2) No. 845 (3) No. ζ-n-i-sa

Claims (2)

[Claims] (1) The optical information of the subject obtained through the optical lens is
an optical prism that separates light into three primary colors of blue and green; an image sensor that converts the optical information of each color separated into an electrical signal; a signal processing circuit that processes an output signal of the image sensor; and a signal processing circuit that processes the output signal of the image sensor. an arithmetic processing circuit that adds and subtracts the output signals of the processing circuits to each other at a constant ratio; A color adjustment circuit characterized by comprising circuit means for changing an addition/subtraction ratio. (2) The color adjustment circuit according to claim 1, wherein the predetermined value is an output signal of a signal processing circuit or an arithmetic processing circuit of another system having the same configuration.