JPH10210495A - White balance controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To finely set an achromatic color extraction range in a simple constitution, to attain the detection of an achromatic color with higher accuracy and the flexible processing, and to secure white balance control with high accuracy by extracting the achromatic color data in every area and calculating the gain control value from the achromatic color extraction data for control of a white balance. SOLUTION: R, G and B data are inputted to a color difference conversion circuit 106 and converted into the data on the B-G and R-G domains. An achromatic color extraction circuit 107 divides the B-G and R-G domains into (nxn) pieces of blocks and decides an extraction range. Then it is decided whether the data sent from the circuit 106 are included in the range of a designated block, so that an achromatic color of the data is decided. Only the data decided achromatic are sent to a white balance control circuit 108. The circuit 108 calculates the gain control value of the R and B data, based on the data where an achromatic color is extracted and performs the gain control of data to attain the white balance control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for white balance control of a digital still video camera or the like. In particular, the present invention relates to a white balance control device which realizes more accurate white balance control by finely setting an achromatic color extraction range. About.

[0002]

2. Description of the Related Art Conventionally, an achromatic color extraction range is set using an achromatic color extraction range surrounded by a straight line as shown in FIG.

As a reference technical document, for example, in Japanese Patent Application Laid-Open No. 4-170889, an achromatic color extraction range is designated by RY and BY data, and is determined by rotating the extraction range as an axis. Digital White Balance Apparatus ".

[0004]

However, in the prior art as described above, since the deviation of the blackbody radiation is a curve, the data separated from the curve of the blackbody radiation is also determined as an achromatic color. However, there is a problem in that white balance control is affected by data other than the deviation due to blackbody radiation, and high-precision white balance cannot be satisfactorily controlled.

[0005] In addition, since a linear achromatic color extraction range as shown in FIG. 6 cannot be set finely, there is a problem that flexible processing according to an image is impossible. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and realizes fine setting of an achromatic color extraction range with a simple configuration, thereby enabling more accurate achromatic color detection and flexible processing. Accordingly, it is an object to realize high-accuracy white balance control.

[0007]

According to a first aspect of the present invention, there is provided a white balance control device, comprising:
A / D conversion is performed on the signal captured by the image sensor, and the signal after the A / D conversion is separated into R, G, and B data.
A white balance control device for adjusting and controlling a white balance based on each of the data of G and B, a color difference converting means for creating BG and RG data from each of the R, G and B data;
The achromatic region extraction range on the BG and RG data is n
An achromatic color extracting unit that divides the image into a plurality of regions, extracts achromatic data for each region, and outputs only the extracted data, and calculates a gain adjustment amount for white balance adjustment from the achromatic color extracted data. And white balance control means for calculating and controlling.

That is, since the achromatic color extracting means is configured so that the achromatic color extracting range can be flexibly set in units of small blocks, it is possible to set the detection range closer to the change in the blackbody radiation, thereby achieving high precision. Achromatic color detection can be performed, and the achromatic color detection area can be easily and flexibly set.

According to a second aspect of the present invention, in the white balance control device, an image is determined from each of the R, G, and B data, and the set value of the achromatic color extraction range is determined based on the determination result. The image processing apparatus further includes an image determination unit that sends the image data to the extraction unit, wherein the achromatic color extraction unit determines an achromatic color extraction range based on a setting value provided by the image determination unit.

That is, in the achromatic color extraction area, image determination is performed, and an achromatic color extraction range is set by using the determination result, thereby enabling achromatic color extraction according to the image, and excluding singular data. Exceptional processing such as this is also possible, and more accurate achromatic color extraction is realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a white balance control device according to the present invention will be described in detail in the order of [Embodiment 1] and [Embodiment 2] with reference to the accompanying drawings.

[First Embodiment] (Structure of First Embodiment) FIG. 1 is a block diagram showing a system structure of a white balance control device according to a first embodiment. In the figure, 101 is an imaging device such as a CCD, 10
Reference numeral 2 denotes an A / D converter for converting analog output data of the image sensor 101 into digital data, and reference numeral 103 denotes an A / D converter 1
02, R,
RGB interpolation circuit for outputting G and B data, 1
Numerals 04 to 105 denote gain circuits for performing gain adjustment for obtaining a white balance between R and B data, 106 denotes a color difference conversion circuit as color difference conversion means for generating BG and RG data from RGB data, and 107 denotes B Achromatic color extraction circuit as achromatic color extraction means for performing achromatic color data extraction based on -G and R-G data and outputting only the extracted data; This is a white balance control circuit as white balance control means for calculating and controlling the extracted data.

FIG. 2 is a block diagram showing the configuration of the achromatic color extraction circuit 107 in FIG. In the figure,
The achromatic color extraction circuit includes a data output circuit 201 for outputting only data determined to be achromatic, and a color difference conversion circuit 10.
A data determination circuit 202 for determining whether or not the data from No. 6 falls within the range of the designated block; and an extraction range determination circuit 203 for determining an extraction range based on an extraction range setting value 204 for a divided block described later. It is composed of

(Operation of First Embodiment) Next, the operation of the white balance control device configured as described above will be described. The data input from the image sensor 101 is subjected to A / D conversion processing by the A / D converter 102 and input to the RGB interpolation circuit 103 as digital data. The RGB interpolation circuit 103 converts the input data into RGB independent digital data.

Further, the respective data of R, G, and B are input to a color difference conversion circuit 106, and the data of B-
The data is converted into data in the G, RG domain. Here, in the achromatic color extraction circuit 107 as shown in FIG. 2, the BG and RG domains as shown in FIG. 3 are divided into n × n blocks, and each block obtained by the division is divided into n × n blocks. For each block, the extraction range determination circuit 203 determines an extraction range for a block designated as an achromatic color extraction region and a block not designated based on the extraction range setting value 204.

Next, the data judgment circuit 202 judges whether or not the data from the color difference conversion circuit 106 is within the range of the designated block, thereby judging the achromatic color of the data. Then, only the data determined to be achromatic is sent from the data output circuit 201 to the white balance control circuit 108 based on the result of the data determination circuit 202.

The white balance control circuit 108 calculates a gain adjustment amount of the R data and the B data based on the data extracted from the achromatic color, and realizes a white balance control by performing a gain adjustment on the data.

(Effects of First Embodiment) Therefore, according to the first embodiment, the achromatic color extraction circuit 107 has a configuration in which the achromatic color extraction range can be flexibly set in block units, so that the blackbody radiation is further improved. Can be set close to the detection range in accordance with the change in the achromatic color, and highly accurate achromatic color detection can be performed, and the achromatic color detection area can be easily and flexibly set.

[Second Embodiment] (Configuration of Second Embodiment) FIG. 4 is a block diagram showing a system configuration of a white balance control device according to a second embodiment. Here, for the system configuration shown in FIG.
An image determination circuit 401 serving as an image determination unit that determines an image from each of the G and B data and transmits a set value of an achromatic color extraction range to an achromatic color extraction circuit 402 serving as an achromatic color extraction unit based on the result of the image determination. Add.

FIG. 5 shows the achromatic color extraction circuit 40 shown in FIG.
2 is a block diagram showing a configuration of FIG. In the figure, the achromatic color extraction circuit 402 is the same as the achromatic color extraction circuit 107 described above.
In response, the extraction determination decision circuit 203
The extraction range is determined based on the set value of the achromatic color extraction range given by

Therefore, other components and their functions are the same as those of the first embodiment, and FIG.
Are denoted by the same reference numerals as in FIG. 2, and description thereof is omitted.

(Operation of Embodiment 2) Next, the operation of the white balance control device configured as described above will be described. The data input from the image sensor 101 is subjected to A / D conversion processing by the A / D converter 102 and input to the RGB interpolation circuit 103 as digital data. The RGB interpolation circuit 103 converts the input data into R, G, and B independent digital data.

Further, the RGB data is input to the color difference conversion circuit 106, and the BG and RG as shown in FIG.
Converted to domain data. Also, this R, G, B
Are also given to the image determination circuit 401, and the image determination circuit 401 performs image determination, and sends the set value of the achromatic color extraction range to the achromatic color extraction circuit 402 based on the result.

Here, in the achromatic color extraction circuit 402 as shown in FIG. 2, the BG and RG domains as shown in FIG. 3 are divided into n.times.n blocks, which are obtained by the division. For each of the blocks, the extraction range determination circuit 203 determines an extraction range for a block designated as an achromatic color extraction region and a block not designated based on the set value given from the image determination circuit 401.

Next, the data judgment circuit 202 judges whether or not the data from the color difference conversion circuit 106 falls within the range of the designated block, thereby judging the achromatic color of the data. Then, only the data determined to be achromatic is sent from the data output circuit 201 to the white balance control circuit 108 based on the result of the data determination circuit 202.

The white balance control circuit 108 calculates a gain adjustment amount of the R data and the B data based on the data extracted from the achromatic color, and realizes a white balance control by performing a gain adjustment on the data.

(Effects of Second Embodiment) Therefore, according to the second embodiment, image determination is performed in the achromatic color extraction area, and the achromatic color extraction range is set using this determination result. Achromatic color extraction according to the image data can be performed, and exceptional processing such as exclusion of peculiar data can be performed, thereby realizing more accurate achromatic color extraction.

[0028]

As described above, according to the white balance control device according to the present invention, the achromatic color extraction means can flexibly set the achromatic color extraction range in small block units. As a result, it is possible to set the detection range closer to the change in blackbody radiation, to perform highly accurate achromatic color detection, and to perform flexible processing, thus realizing highly accurate white balance control. Further, the setting of the achromatic color detection area is easy and can be flexibly set.

According to the white balance control device of the present invention, image determination is performed in the achromatic color extraction area, and the achromatic color extraction range is set using the determination result. Achromatic color extraction according to the image data, and exceptional processing such as exclusion of peculiar data can be performed, so that more accurate achromatic color extraction can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a white balance control device according to a first embodiment.

FIG. 2 is a block diagram illustrating a configuration of an achromatic color extraction circuit in FIG. 1;

FIG. 3 is an explanatory diagram showing a conversion example of BG and RG domains and an achromatic color extraction range / blackbody radiation curve according to the present invention.

FIG. 4 is a block diagram showing a system configuration of a white balance control device according to a second embodiment.

FIG. 5 is a block diagram showing a configuration of an achromatic color extraction circuit in FIG. 4;

FIG. 6 is an explanatory diagram showing an achromatic color extraction range and a blackbody radiation curve in the related art.

[Explanation of symbols]

 Reference Signs List 101 imaging device 102 A / D converter 103 RGB interpolation circuit 106 color difference conversion circuit 107, 402 achromatic color extraction circuit 108 white balance control circuit 401 image determination circuit

Claims (2)

[Claims] 1. A / D conversion of a signal fetched by an image sensor, separation of the signal after the A / D conversion into R, G, and B data, based on the R, G, and B data. In a white balance control device for adjusting and controlling the white balance, the R, G,
A color difference conversion unit for creating BG and RG data from each of the B data; and dividing the achromatic region extraction range on the BG and RG data into n × n regions. Achromatic color extraction means for extracting achromatic color data for each and outputting only the extracted data, white balance control means for calculating and controlling a gain adjustment amount for white balance adjustment from the achromatic color extraction data, A white balance control device comprising: 2. The image processing apparatus according to claim 1, further comprising: an image determination unit that determines an image from each of the R, G, and B data and sends a set value of an achromatic color extraction range to the achromatic color extraction unit based on the determination result. 2. The white balance control device according to claim 1, wherein the extraction unit determines an achromatic color extraction range based on a setting value provided by the image determination unit.