KR950006041B1 - Auto white balance control device in a camcorder - Google Patents

Abstract

The frame is divided into 64 subframes and the white point is calculated by comparing R and B component of each subframe. The apparatus includes a color signal extractor and gain adjuster (20) for extracting color signal from input image signal and for adjusting level the color signal, a multiplexer (30) for multiplexing output signal of the color signal extractor and gain adjuster (20), an A/D converter (40) for converting output signal of the multiplexer (30), a frame divider (70) for dividing a frame by 64 numbers, and an integrator (50) for integrating output signals of the A/D converter (40) and the frame divider (70) by subframe units.

Description

Camcorder Digital Camera Processing Auto White Balancer

1 is a block diagram schematically showing an auto white balance circuit of a conventional camcorder.

2 is a block diagram schematically showing an auto white balance circuit of a camcorder according to the present invention.

3 is a detailed circuit diagram of the multiplexer shown in FIG.

4 is a detailed block diagram of the screen division shown in FIG.

5 is a diagram showing an example of screen division according to the present invention.

6 is a control flowchart performed in the microcomputer according to the present invention.

* Explanation of symbols for main parts of the drawings

10: imaging device (CCD) 20: color separation and gain control unit

30: Multiplexer 40: A / D Converter

50: full adder 60: microcomputer for auto white balance

70: screen division part 71: screen division counter part

72: horizontal / vertical division address unit 73: horizontal / vertical division decoder unit

The present invention relates to an apparatus for automatically adjusting a white balance of a camcorder, and more particularly, to an apparatus for performing auto white balance using a digital conversion and a screen division method of color signal components of an image signal. It is about.

1 is a block diagram schematically showing a conventional auto white balance circuit. The conventional circuit includes a gate pulse control unit which performs gate pulse control by receiving a signal received from the white region discrimination unit and a white region discrimination unit for determining a white region of a chrominance signal and a chrominance signal (RY, BY). A comparator for receiving the output signal of the gate pulse controller and comparing the signal, an up / down counter circuit for receiving an output signal of the comparator and receiving a V-drive signal to perform an up / down coefficient, and the up / down counter circuit The D / A converter circuit converts the digital signal output from the analog signal to an analog signal.

Since the conventional auto white balance circuit configured as described above is configured to control the up / down counter with the V-drive signal, the white point must be found for every field. As a result, the screen shakes because there is a great possibility of change, and the color difference signal (RY, BY) component is defined on the whole screen as an equal (feeling equal) area, and RY and BY are controlled in the area. Since components and B components must be controlled to be continuously compared-equalized, it is difficult to find the correct white point and the circuit becomes very complicated, which leads to many problems in application to a compact camcorder.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and extracts color signal components (RY, BY) from video signals, converts them to digital, divides the entire screen into 64, and compares the R and B components of each divided region with each other. It is to provide an auto white balance device with a simple configuration that finds an accurate white point.

In order to achieve the above object, the present invention provides an apparatus for performing auto white balance using a color signal of a video signal, comprising: an image for converting an optical image of a subject input through a lens and a microcomputer for auto white balance into a Youngsan signal; A color separation and gain control unit for extracting a color signal component from an image signal received from the device and receiving a control signal output from the microcomputer and outputting an appropriate signal, and receiving an output signal from the color separation and gain control unit A multiplexer for multiplexing, an A / D converter for converting an analog signal output from the multiplexer into a digital signal, an H-dry signal, a V-dry signal, and a 4fsc signal to receive the screen, and divides the screen into a plurality of predetermined areas. A screen divider for outputting the divided control signal, the A / D converter and the screen divider; Receiving a signal output from the unit and to the integral by a predetermined plurality of regions, it characterized by comprising parts integral to output the data.

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

2 is a diagram schematically showing a circuit configuration of an auto white balance device according to the present invention.

Receiving a signal output from the image pickup device 10 for converting an optical image of a subject input through a lens into an image signal as shown in the drawing, and extracting color signal components RY and BY from the image signal; At the same time, the color signal is output to the multiplexer according to the color signal magnitude control signal output from the microcomputer.

FIG. 3 is a detailed circuit diagram of the multiplexer, which is composed of two AND gates and one OR gate, and multiplexes the color signal components received from the color separation and gain control unit and outputs them to an A / D converter which will be described below. In the A / D converter, the analog signal output from the multiplexer is converted into a digital signal and sent to a full adder.

4 is a detailed block diagram of the screen splitter shown in FIG.

As shown in the drawing, the screen is equally divided into 64 regions using an H-Drive Signal, a V-Drive Signal, and a 4fsc signal. The drive signal, the V-drive signal, and the 4fsc signal are input to the screen division counter section 71 to count 64 areas, and then the 64 division control signal is passed through the horizontal / vertical division address unit 72 and the horizontal / vertical division decoder unit. It consists of a process that is output to the integrator.

5 is a diagram showing an example of screen division, which is divided into eight regions on the horizontal axis and eight regions on the vertical axis. In the division method, the horizontal axis is divided using 4fsc and the H-drive signal, and the vertical axis is divided using the H-drive signal and the V-drive signal. As described above, the digitalized color signal component sent to the integrating unit is integrated for each of the 64 divided areas, and the data is sent to the auto white balance microcomputer, respectively. In the microcomputer, as shown in FIG. 6, which is a flow chart based on the color signal " R-Y ", the data is compared and analyzed to generate a control signal to find a white point where the R and B components are equal. That is, the microcomputer compares whether the R component and the B component are the same for each region over the entire 64 regions. As a result of the comparison, if there is an area where R-Y = B-Y, only the area is considered valid data, and the sum is averaged to recognize the point as a white point and the size of R-Y and R-Y is controlled accordingly.

On the other hand, the auto white balance of the present invention is performed on a field basis, but not on every field, but is performed by selecting one of several fields, for example, one of nine fields, and the time is very short. Not only can you do this, you can use other actions, such as Auto Focus, for the remaining eight field times.

In more detail, the R-Y component is selected in the first field to process the above-described data, the B-Y component is selected in the next field to process the data, and the microcomputer compares and controls each other.

In addition, some matters applied to the present invention, that is, the selection of RY and BY may use a multiplexer, and the number of bits of the full adder, the communication means in the microcomputer, and the amount of data transmitted once may be adjusted appropriately. . For example, if the A / D sampling clock is about 14.3 MHz, the integral full add bits will require 48 bits (if the A / D bits are 6 bits).

On the other hand, the gist of the present invention has been described with reference to a specific embodiment for a simple circuit configuration possible, but of course, the auto white balance can be performed by including the G component in the same manner, for example, R = G = B, G = The B system, the R = G system, and the like can be implemented without departing from the gist of the present invention.

As described above, according to the present invention, it is controlled once every 9 fields by digital method, so that the change of the screen is small, so that the visual burden is not only reduced, but also the circuit configuration is simple, and it can be applied to the ultra-compact camcorder which is widely produced recently. That has an outstanding effect.

Claims (3)

An apparatus for performing auto white balance using color signals in a video signal, comprising: a microcomputer for auto white balance; Color separation and gain for extracting a color signal component from an image signal received from an image pickup device for converting an optical image of a subject input through a lens into an image signal and receiving a control signal output from the microcomputer and outputting an appropriate signal. A controller; A multiplexer which receives the output signal from the color separation and gain control unit and performs multiplexing; An A / D converter for converting an analog signal output from the multiplexer into a digital signal; A screen splitter which receives an H-dry signal, a V-dry signal, and a 4fsc signal, divides the screen into a plurality of predetermined regions, and outputs a split control signal; And an integrating unit for receiving signals output from the A / D converter and the screen dividing unit, integrating the predetermined areas, and outputting the data. The microcomputer of claim 1, wherein the auto-white balance microcomputer compares and analyzes the signal output from the integrating unit, and if there is an area where the R and B components are the same, sum and average the effective data only for the area and whiten the point. A digital camera processing auto white balance device for a camcorder, characterized in that it is a microcomputer that recognizes a point and outputs a control signal of an appropriate size. The digital camera processor auto white balance apparatus of claim 1, wherein the screen divider comprises a screen division counter unit horizontal / vertical division address unit and a horizontal / vertical division decoder unit.