JPH11205812A - White balance control method and system thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly accurate white balance adjustment by increasing achromatic color extract accuracy. SOLUTION: R-G, B-G domains are divided into plural blocks as a mesh and a specific block is set as an achromatic color extract area. An achromatic color discrimination circuit 7 discriminates whether or not color difference data of each pixel are included in the achromatic color area block for to the entire image or a designated area. A counter 112 counts number of pixels, including the color difference data for each achromatic color area block and an integration circuit 9 integrates R, G, B values of the pixels. A maximum value detection circuit 10 detects a maximum count value, and a gain control circuit 12 calculates R, B gains by the use of the integrated R, G, B values in the achromatic color area block and sets the gains to R, B gain circuits 13, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white balance control technique for image data, and more particularly to a white balance control suitable for an image apparatus such as a digital video camera or a digital still camera using a CCD image pickup device. Method and apparatus.

[0002]

2. Description of the Related Art Conventionally, most white balance control devices designate a certain area, such as a black body radiation curve shown by a straight line, as shown in FIG. 8 as an achromatic color extraction range and perform achromatic color extraction. I have.

Japanese Patent Laid-Open No. 4-17008 discloses a white balance apparatus in which an achromatic color extraction range is similarly designated by RY and BY data and the extraction range is rotated about an axis.
No. 89 is disclosed. In addition, a white balance apparatus that divides a screen into a plurality of regions and performs achromatic color extraction for each region is disclosed in the publication and Japanese Patent Laid-Open No. 5-292533.

[0004]

According to the method of designating a certain area surrounding a black body radiation curve with a straight line as an achromatic color extraction range as shown in FIG. 8, the achromatic color extraction range is determined according to the target image or the like. It is difficult to increase the precision of white balance adjustment by finely and flexibly setting the precision of achromatic color extraction.

In general, when achromatic colors are extracted, the probability that a situation in which a plurality of light sources having different color temperatures are present in one image is low, and the color shift of achromatic colors due to the color temperature of the light sources is one. It is thought to occur in many ways. However, when there is a color similar to the change in color temperature in an image, the peak of the distribution of data determined to be achromatic appears at a plurality of locations, and in many cases data as if there are a plurality of light sources is obtained. is there. In such a case, in the above-described related art, since the integrated value of all data in the achromatic color extraction range is used for white balance adjustment, that is, data that is not actually achromatic is treated as achromatic. For,
In some cases, accurate white balance adjustment cannot be achieved.
This problem is the same even when the image is divided into a plurality of regions and handled.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to flexibly and finely set an achromatic color extraction range to enable high-accuracy white balance adjustment. That is, it is possible to reduce the achromatic color extraction error to enable high-accuracy white balance adjustment even for image data in which the peak of the distribution of data determined to be achromatic appears at a plurality of locations, It is necessary to flexibly respond to shooting conditions to enable high-accuracy white balance adjustment, and to realize high-accuracy white balance adjustment with a simple device configuration.

[0007]

According to a first aspect of the present invention, there is provided a white balance control method according to the present invention.
The color difference data domain is mesh-divided into a plurality of blocks, a plurality of specific blocks are set as achromatic color extraction regions, and R, R, and R of image data obtained by the image sensor are set.
The color difference data is generated from the G and B values, the number of color difference data included in each block set as the achromatic color extraction area is counted, and the corresponding R, G and B values are integrated, and the count value is maximized. R, B, G for the block of
The integrated value is used for white balance adjustment of image data.

According to the white balance control method of the present invention, the color difference data domain is divided into a plurality of blocks by mesh, and a plurality of specific blocks are set as an achromatic color extraction area. The balance control data is set, color difference data is generated from the R, G, and B values of the image data obtained by the image sensor, and for each block set as an achromatic color extraction area,
The number of color difference data included therein is counted, and white balance control data set corresponding to the block having the largest count value is used for white balance adjustment of image data.

According to a third aspect of the present invention, there is provided a white balance control method, wherein a color difference data domain is divided into a plurality of blocks by mesh, and a plurality of achromatic color extraction regions each composed of one or more specific blocks are set. , Color difference data is generated from the R, G, B values of the image data obtained by the image sensor, the number of color difference data included in each achromatic color extraction area is counted, and the corresponding R, G, B values are calculated. The integrated R, B, and G values of the achromatic color extraction area having the largest count value are used for white balance adjustment of image data.

According to a fourth aspect of the present invention, there is provided a white balance control method comprising dividing a chrominance data domain into a plurality of blocks, setting a plurality of specific blocks as an achromatic color extraction area, and obtaining the blocks by an image sensor. The color difference data is generated from the R, G, and B values of the image data, and the number of color difference data included in each block set as an achromatic color extraction area is counted, and the corresponding R, G, and B data are correspondingly calculated.
The values are integrated, a distribution of count values for blocks set as the achromatic color extraction area is obtained, a plurality of specific blocks are selected based on the distribution, and R, B, and G values of the selected blocks are calculated. It is characterized in that the total value of the integrated values is used for white balance adjustment of the image data.

According to a fifth aspect of the present invention, there is provided a white balance control device for setting a plurality of specific blocks among a plurality of blocks obtained by dividing a chrominance data domain into meshes as an achromatic region, and an image obtained by an image sensor. Means for generating color difference data from the R, G, and B values of the data, means for determining whether the generated color difference data is included in a block set as an achromatic color extraction area, and means for setting as an achromatic color extraction area Means for counting the number of color difference data determined to be included in each block, and R, G, B corresponding to the color difference data determined to be included in each block set as an achromatic color extraction area Select a specific block by mutually comparing the means for integrating values and the count value for each block set as an achromatic color extraction area Means that, characterized by comprising a means for performing white balance adjustment of the image data on the basis of R for the selected block, B, and integrated value of G values.

According to a sixth aspect of the present invention, there is provided a white balance control device for setting a plurality of specific blocks among a plurality of blocks obtained by dividing a chrominance data domain into meshes as an achromatic color extraction region, and setting the achromatic color region as an achromatic color region. Means for storing white balance control data corresponding to each block, and R, G, B of image data obtained by the image sensor.
Means for generating color difference data from the values, means for determining whether or not the generated color difference data is included in a block set as an achromatic color extraction area, and means for each block set as an achromatic color extraction area Means for counting the number of pieces of color difference data determined to be detected, and the count value for each block set as an achromatic color extraction area are compared with each other, and the white balance stored corresponding to the block having the largest count value is stored. It is characterized by comprising means for selecting control data and means for adjusting the white balance of the image data according to the selected white balance control data.

According to a seventh aspect of the present invention, there is provided a white balance control device for setting a plurality of achromatic color extraction areas each including a group of one or more specific blocks among a plurality of blocks obtained by dividing a chrominance data domain into meshes. Means for generating color difference data from the R, G, B values of image data obtained by the image sensor, means for determining whether or not the generated color data is included in the achromatic color extraction area, A means for counting the number of color difference data determined to be included in each area, a means for integrating R, G, and B values corresponding to the color difference data determined to be included in each achromatic color extraction area; Means for selecting a specific achromatic color extraction area by inter-comparing the count values relating to the achromatic color extraction area, and means for selecting the specific achromatic color extraction area based on the integrated value of the R, B, and G values relating to the selected achromatic color extraction area Characterized by comprising the means for performing white balance adjustment of the image data.

[0014] The white balance control device according to the eighth aspect of the present invention provides a white balance control device for setting a specific plurality of blocks among a plurality of blocks obtained by dividing a color difference data domain into meshes as an achromatic region, and an image obtained by an image sensor. Means for generating color difference data from the R, G, and B values of the data, means for determining whether the generated color difference data is included in a block set as an achromatic color extraction area, and means for setting as an achromatic color extraction area Means for counting the number of color difference data determined to be included in each block, and R, G, B corresponding to the color difference data determined to be included in each block set as an achromatic color extraction area Means for integrating values, and a distribution of count values for blocks set as an achromatic color extraction area, and a plurality of specific blocks based on the distribution. , A means for calculating the total value of the integrated values of the R, B, and G values for the selected blocks, and a white balance of the image data based on the calculated total value of the R, G, and B values. Means for performing adjustment.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

<Embodiment 1> In one embodiment of the present invention, RG and BG data are used as color difference data. For example, as shown in FIG.
Mesh division into many blocks in each axis direction of BG,
A specific block (block shaded in FIG. 2) among these blocks is set as an achromatic color extraction area. In the example of FIG. 2, a block along the blackbody radiation curve is set as the achromatic color extraction area, but the present invention is not limited to this.

After setting such an achromatic color extraction area, the R, G, B of the image data obtained by the image pickup device is set.
Color difference data is generated from the values, and for each block set as an achromatic color extraction area, the number of color difference data included in the block is counted and the corresponding R, G, B values are integrated. Then, R for the block having the largest count value,
The integrated value of the B and G values is used for white balance adjustment of the image data.

As described above, since the achromatic color extraction area is set in small block units, the setting can be performed finely and flexibly. Then, an achromatic determination is performed for each of these blocks, a block having the largest number of pixels determined to be an achromatic color is selected as a substantial achromatic extraction area, and the integrated value of the R, G, and B values is used as a white balance. Since it is used for adjustment, compared to the case where the entire achromatic color extraction area is used, even when the distribution of data determined to be achromatic appears in multiple places, a high level corresponding to only the color misregistration portion of the achromatic color data is used. Accurate white balance adjustment becomes possible.

FIG. 1 shows a configuration example of a white balance control device according to the present embodiment. In FIG. 1, reference numeral 1 denotes a CCD image sensor for picking up an image, which serially outputs analog image data in frame units (or field units), one pixel at a time. The analog image data is converted into digital image data by the A / D converter 2 and input to the color interpolation processing circuit 3. The color interpolation processing circuit 3 performs data interpolation on the digital image data according to the filter arrangement on the imaging surface of the CCD imaging device 1 to convert the digital image data into R, G, B data, and inputs the data to the color conversion processing circuit 4. . The color conversion processing circuit 4 converts the R, G, B data into color difference data (here, R-
G, BG data).

The mesh division processing circuit 5 performs mesh division of the color difference data domain as shown in FIG. 2, and provides information on the mesh division (for example, the number of divisions) to the mesh position detection circuit 6. The mesh position detection circuit 6 detects which mesh position of the input RGB data and BG data of each pixel is on the RG axis and BG axis of the color difference data domain, respectively, and detects an achromatic color. Notify 7. A data table 8 holds data for identifying a block set as an achromatic color extraction area on the color difference data domain. The data held here is, for example, binary data (shown in hexadecimal notation in FIG. 2) that designates a block set as an achromatic region for each mesh position on the R-G axis as shown on the right side of FIG. Is). The achromatic color determination circuit 7 compares the mesh position of the color difference data provided from the mesh position detection circuit 6 with the achromatic color extraction area setting data of the data table 8 for each pixel, and the color difference data is used as an achromatic color extraction area. When the block is included in a certain set block, an increment signal related to the block is output to the counter 11 and an integration instruction signal related to the block is output to the RGB value integration circuit 9. That is, the achromatic color determination circuit 7, the mesh division processing circuit 5, the mesh position detection circuit 6, and the data table 8
Constitutes means for setting the mesh division and the achromatic color area, and determining whether or not the color difference data is included in the block set as the achromatic color extraction area.

When an increment signal related to a certain block is given from the achromatic color determination circuit 7, the counter 11 increments the count value related to the block by one, thereby setting each block set as an achromatic color extraction area. Each time, the number of color difference data, that is, the number of pixels determined to be included in the data is counted. The RGB value integration circuit 9 receives the integration instruction signal related to a certain block from the achromatic color determination circuit 7 and outputs R,
By taking in and integrating the values of the G and B data, an integrated value of the R, G, and B values corresponding to the color difference data determined to be included in each block set as an achromatic region is obtained. . The count value of the counter 11 and the integrated value of the RGB value integrating circuit 9 are cleared before input of each frame (or each field).

The above-described processing by each unit is repeatedly performed on the entirety of one frame (or one field) or a designated area. At the end of this process, the maximum value detection circuit 10 detects the maximum count value by comparing the count values obtained by the counter 11 for each block set as the achromatic color extraction area, and detects the maximum count value. Is selected and notified to the RGB integrating circuit 9. The RGB integrating circuit 9 outputs an integrated value of R, G, and B values for the block selected by the maximum value detecting circuit 10 to the gain control circuit 12. The count value corresponding to the block is also output from the counter 11 to the gain control circuit 12.

In the gain control device 12, the received R,
An R gain value and a B gain for white balance adjustment of the next frame (or next field) based on the integrated value of the G and B values, or based on the integrated value of the R, G and B values and the count value. Before inputting the image data of the next frame (next field), the R gain circuit 13 and the B gain circuit 1
4 respectively. Thus, the gains of the R and B data are adjusted by the R gain circuit 13 and the B gain circuit 14, and the R, B, and G data with the white balance adjusted can be obtained.

In the gain control circuit 12, R, G, B
When the integrated value of the values is Rs, Gs, Bs and the count value is C, the R and B gain values are calculated by, for example, R gain value = Rs / Gs (1) B gain value = Bs / Gs (2) .

It should be noted that the calculated R and B gain values are weighted according to the distance (the degree of color misregistration) from the state where the white balance is maintained (the state where both the R and B gain values are 1). May be attached. For example, when the gain setting range is, for example, 0.5 to 2, the calculated gain is set to 1 when the calculated gain is 1, and when the calculated gain is 0.5 or 2, the gain value is set to 20%. A method may be used in which the gain value is reduced and the gain value is changed linearly during that time.

Alternatively, the result is the same as that obtained by the equations (1) and (2), but the count value C is also used, and R gain value = (Rs / C) / (Gs / C) (3) B gain Value = (Bs / C) / (Gs / C) (4) The R and B gain values may be calculated. This is Rs
By checking the values of / C and Gs / C, there is an advantage that an error of the count value or the integrated value of the R, B, and G values (eg, overflow of a register for holding the integrated value) can be checked.

As for the use of the count value C, control may be performed such that when the count value C becomes a certain value or less, gain control for setting the gain value to 1 is not performed. Further, for example, during monitoring (when a captured image is displayed continuously as a moving image), a sudden gain change may visually give a sense of incongruity. Alternatively, the gain value may be controlled.

Note that RGB data and BG data are used as color difference data.
RY and BY data (Y is luminance) may be used instead of the data. Further, the processing steps or means for white balance control in this embodiment can be realized by a program using a microprocessor or the like. This is the same in the embodiments described later.

<Embodiment 2> In another embodiment of the present invention, as in the case of Embodiment 1, for example, as shown in FIG. Although a specific block is set as an achromatic color extraction area by mesh division in the direction, unlike the first embodiment, white balance control data corresponding to each block as an achromatic color extraction area is set in advance, and this is set to, for example, a memo. And memorize it. Then, R, G, B of the image data obtained by the image sensor
Generates color difference data from the values, counts the number of color difference data included in each block set as an achromatic color extraction area, and sets the white balance control corresponding to the block with the maximum count value The data is used for white balance adjustment of the image data.

FIG. 3 shows an example of the configuration of the white balance control device of this embodiment. 3, reference numerals 1 to 8, 9, and 10 denote the same or corresponding parts to the same reference numerals in FIG. 31 is RB
This is a gain data memory in which R gain values and B gain values calculated in advance are stored as white balance control data corresponding to each block set as an achromatic color extraction area. 32 is a gain control circuit.

Next, the operation will be described. Analog image data of a frame unit (or a field unit) is serially output one pixel at a time from the CCD image pickup device 1.
The data is converted into digital image data by the D converter 2 and input to the color interpolation processing circuit 3 to be converted into R, G, B data. The color conversion processing circuit 4 generates color difference data (here, RG, BG data) from the R, G, B data. The mesh positions of the RGB data and BG data of each pixel are detected by the mesh position detection circuit 6 and input to the achromatic color determination circuit 7. The achromatic color determination circuit 7 compares the mesh position of the chrominance data with the achromatic color extraction area setting data in the data table 8, and determines whether the chrominance data is included in the block set as the achromatic color extraction area. . When it is determined that the color data is included in a certain block, the counter 11 increments the count value related to the block by 1 in accordance with the increment signal output from the achromatic color determination circuit 7.

The above processing by each unit is repeatedly performed on the entire one frame (or one field) or a designated area. At the end of this process, the maximum value detection circuit 10 detects the maximum count value by comparing the count value of each block obtained by the counter 11, and sets the maximum count value for the block corresponding to the count value. The R and B gain values are output from the RB gain data memory 31 to the gain control circuit 32. Gain control circuit 32
Converts the received R gain value and B gain value into the R gain circuit 13 and the B gain value before inputting the next frame (or next field).
These are set in the gain circuits 14, respectively. By such control, the gains of the R and B data are adjusted, and a white balance is obtained.

According to the present embodiment, since the integration of the R, G, and B values, the holding of the integrated values, and the calculation of the R, G gain values are not required, the same high circuit configuration as that of the first embodiment can be obtained. Accurate white balance adjustment becomes possible. This reduction in the amount of calculation is also advantageous when white balance control is performed by a program using a microprocessor or the like.

In this embodiment, also in the first embodiment,
Similarly, the maximum count value from the counter 11 is also input to the gain control circuit 32, and the gain control circuit 32
The count value may be used for gain control.

<Embodiment 3> In another embodiment of the present invention, as in the example shown in FIG. 2, the color difference data domain is mesh-divided in each of the RG and BG axes. Instead of setting specific individual blocks as achromatic color extraction regions, specific blocks are grouped and a plurality of achromatic color extraction regions including at least one block are set. For example, four achromatic color extraction areas A, B, C, and D as shown in FIG. 5 or FIG. 6 are set. Then, color difference data is generated from the R, G, and B values of the image data obtained by the image sensor, and the number of color difference data included in each achromatic color extraction region is counted, and the corresponding R, G, and B are included.
The values are integrated, and the integrated value of the R, B, and G values relating to the achromatic color extraction region having the largest count value is used for white balance adjustment of the image data.

According to the present embodiment, a suitable white balance adjustment corresponding to various photographing conditions can be performed depending on how blocks are grouped as an achromatic color extraction area. For example, achromatic color misregistration position that is most likely to be obtained under specific shooting conditions, such as outdoor shooting, indoor shooting, outdoor shooting at sunset, sunny day or cloudy day, etc. Blocks are grouped for each (for example, in FIG. 6, blocks corresponding to achromatic color misregistration positions under fluorescent light illumination are grouped as an achromatic color extraction region C, and the blocks are classified into an achromatic color extraction area C at sunset or under incandescent light illumination. The blocks corresponding to the color misregistration positions of the chromatic colors are grouped as an achromatic color extraction region B, and the blocks corresponding to the achromatic color misregistration positions on a cloudy day or under illumination by a bluish light source are grouped as an achromatic color extraction region D. ), It is possible to reduce errors in achromatic color determination. Further, for example, when it is known that the photographing is not performed under a light source with a strong reddish color, the achromatic color extraction area D in FIG. 6 is divided into a group of color shift positions under natural light and a group of color shift positions under artificial light. The achromatic color detection accuracy can be increased by dividing the two.

FIG. 4 shows a configuration example of the white balance control device according to the present embodiment. 4, reference numerals 1 to 4, 8 to 10, and 12 denote the same or corresponding parts to the same reference numerals in FIG. However, the counter 11 counts for each block group, that is, for each achromatic color extraction area, and the RGB value integration circuit 9 integrates the R, G, and B values for each achromatic color extraction area. A group division processing circuit 45 sets an achromatic region by grouping the mesh division blocks in the color difference data domain as described above, and supplies grouping information to a group determination circuit 46. The group determination circuit 46 refers to the grouping information, determines which achromatic color extraction region contains the color difference data to be input, and when it is determined that the input color difference data is included in a certain achromatic color extraction region, the group determination circuit 46 relates to the achromatic color extraction region. The increment signal and the R, G, B value integration signal are sent to the counter 11 and the RGB value integration circuit 9, respectively.

Next, the operation will be described. Analog image data of a frame unit (or a field unit) is serially output one pixel at a time from the CCD image pickup device 1.
The data is converted into digital image data by the D converter 2 and input to the color interpolation processing circuit 3 to be converted into R, G, B data. The color conversion processing circuit 4 generates color difference data (here, RG, BG data) from the R, G, B data. The group determination circuit 46 determines whether or not the color difference data of each pixel is included in the achromatic color extraction area. When it is determined that the color difference data is included in a certain achromatic color extraction area, the RGB value integrated signal and the increment signal output from the group determination circuit 46 are output. , The RGB value integrating circuit 9 calculates the R,
The G, B values are taken in, and the R, G, B
The counter 11 increments the count value of the achromatic color extraction area by 1 in addition to the integrated value.

The above-described processing by each unit is repeatedly performed on the entire one frame (or one field) or a designated area. At the end of this process, the maximum value detection circuit 10 detects the maximum count value by comparing the count values of the achromatic color extraction regions obtained by the counter 11 and detects the achromatic color extraction value corresponding to the count value. The integrated value and count value of the R, G, and B values corresponding to the area are output from the RGB value integrating circuit 9 and the counter 11 to the gain control circuit 12, respectively. The gain control circuit 12 determines the R gain and the B gain using the integrated value of the received R, G, and B values, or the integrated value and the count value, as in the first embodiment. The R gain circuit 13 and the B gain circuit 14 are set before the frame (or the next field) is input.

In this embodiment, since a group of blocks in the color difference data domain is set as an achromatic color extraction area, the achromatic color extraction area is different from the case where each block is set as an achromatic color extraction area as in the first embodiment. As the number of extraction regions decreases, the scale of the counter 8 and the RGB integration circuit can be reduced.

<Embodiment 4> In another embodiment of the present invention, the chrominance data domain is divided into a large number of blocks by mesh, and a specific block in those blocks is set as an achromatic color extraction area, and the image pickup device uses the same. Color difference data is generated from the R, G, and B values of the obtained image data, and the number of color difference data included in each block set as an achromatic color extraction area is counted and the corresponding R, G,
The G and B values are integrated. Up to this point, the process is the same as that of the first embodiment, but instead of selecting the block having the largest count value among the blocks set as the achromatic color extraction area,
The distribution of the count values of the blocks set as the achromatic color extraction area (for example, when the achromatic color extraction area as shown in FIG. 2 is set, the count values are arranged from the upper left block to the lower right block). Histogram, etc.), and based on the distribution, for example, select a block group that is consecutively adjacent within a certain distance from the maximum value with a count value being equal to or greater than a threshold value (however, even if the count value is large, Blocks with local distribution in are ignored as singularities.) Then, the sum of the integrated values of the R, B, and G values for the selected blocks is used for white balance adjustment of the image data. As described above, according to the present embodiment, the light source at the time of shooting is estimated based on the distribution of the count value, and the data of the achromatic color extraction area corresponding to the achromatic color misregistration position under the light source is used. Highly accurate white balance adjustment is possible.

FIG. 7 shows a configuration example of the white balance control device according to the present embodiment. In FIG. 7, reference numerals 1 to 9 and 11 denote the same or corresponding portions as those in FIG. Reference numeral 71 denotes a distribution detecting circuit for selecting a plurality of specific blocks by taking distribution of the count value of the counter 11, and 73 denotes a distribution detecting circuit 71.
The adder circuit 74 obtains the total value of the count values of the block selected by (1), and the adder circuit 74 obtains the total value of the integrated values of the selected R, G, and B values. These total values are input to the gain control circuit 12.

Next, the operation will be described. Analog image data of a frame unit (or a field unit) is serially output one pixel at a time from the CCD image pickup device 1.
The data is converted into digital image data by the D converter 2 and input to the color interpolation processing circuit 3 to be converted into R, G, B data. The color conversion processing circuit 4 generates color difference data (here, RG, BG data) from the R, G, B data. The mesh positions of the RGB data and BG data of each pixel are detected by the mesh position detection circuit 6 and input to the achromatic color determination circuit 7. The achromatic color determination circuit 7 compares the mesh position of the chrominance data with the achromatic color extraction area setting data in the data table 8, and determines whether the chrominance data is included in the block set as the achromatic color extraction area. . When it is determined that the color data is included in a certain block, the RGB value integrating circuit 9 calculates the R, G, and B values of the pixel at that time according to the RBG value integrating signal and the increment signal output from the achromatic color determining circuit 7. The fetched value is added to the integrated value of the R, G, and B values related to the block, and the counter 11 counts the count value related to the block by one.
Only increment.

The above-described processing by each unit is repeatedly performed on the entirety of one frame (or one field) or a designated area. At the end of this process, the distribution detection circuit 71 selects a plurality of specific blocks by taking the distribution of the count values, and calculates the integrated values of the R, G, B values and the count values for these blocks and the RGB value integrated circuit 9. And the output from the counter 11 to the addition circuit 74 and the addition circuit 73, respectively, and the total value thereof is input to the gain control circuit 12. The gain control circuit 22 uses the total value of the integrated values of the received R, G, and B values or the total value of the total value and the count value to calculate the R gain value by the same calculation method as in the first embodiment. And the B gain value are determined and set in the R gain circuit 13 and the B gain circuit 14 before inputting the next frame (or next field). By such control, the gains of the R and B data are adjusted, and a white balance is obtained.

[0045]

As is apparent from the above description, the following effects can be obtained according to the present invention.

(1) According to the first or fifth aspect of the invention, the achromatic color extraction area can be set finely and flexibly, and an achromatic color area (block) having a large count value of color difference data is selected. By using the integrated values of the G and B values for white balance adjustment, even for an image in which the distribution of data determined to be achromatic appears in a plurality of places, a high image according to the color shift component of the achromatic data is obtained. It is possible to obtain effects such as enabling accurate white balance adjustment.

(2) According to the second or sixth aspect of the present invention, the same effects as those of the first or fifth aspect can be obtained, and the R, G,
Since the integration of the B value, the holding of the integrated value, and the calculation of the R and B gain values are not required, the configuration of the white balance control device can be simplified and the amount of calculation is reduced as compared with the fifth aspect of the invention. It is possible to obtain an effect that the white balance control can be easily performed by a program using a microprocessor or the like having a large restriction in speed.

(3) According to the third or seventh aspect of the present invention, the achromatic color extraction region corresponding to various photographing conditions can be flexibly set by grouping the mesh division blocks of the color difference data domain, and various photographing conditions can be set. The white balance can be adjusted with high accuracy for the image. In addition, the circuit scale for counting the color difference data, integrating the R, G, and B values, and holding the integrated value is reduced by reducing the number of achromatic color extraction areas as compared with the first or fifth aspect of the invention. And the like.

(4) According to the fourth or eighth aspect of the present invention, the achromatic color extraction region can be set finely and flexibly, and the light source at the time of photographing the image is estimated based on the distribution of the count value. It is possible to obtain effects such as a high-accuracy white balance adjustment using an integrated value of R, G, and B values of an achromatic region corresponding to a color misregistration position under a light source.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a white balance control device according to the present invention.

FIG. 2 is a diagram illustrating an example of mesh division of color difference data and setting of an achromatic color extraction region.

FIG. 3 is a block diagram showing another example of the white balance control device according to the present invention.

FIG. 4 is a block diagram showing another example of the white balance control device according to the present invention.

FIG. 5 is a diagram illustrating an example of setting an achromatic color extraction region by grouping mesh division blocks in a color difference data domain.

FIG. 6 is a diagram illustrating another example of setting an achromatic color extraction region by grouping mesh division blocks in a color difference data domain.

FIG. 7 is a block diagram showing another example of the white balance control device according to the present invention.

FIG. 8 is an explanatory diagram of a conventional achromatic color extraction range.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CCD imaging element 2 A / D converter 3 Color interpolation processing circuit 4 Color difference conversion processing circuit 5 Mesh division processing circuit 6 Mesh position detection circuit 7 Achromatic color judgment circuit 8 Data table 9 RGB value integration circuit 10 Maximum value detection circuit 11 Counter Reference Signs List 12 gain control circuit 13 R gain circuit 14 B gain circuit 31 RB gain data memory 32 gain control circuit 45 group division processing circuit 46 group determination circuit 71 distribution detection circuit 73, 74 addition circuit

Claims (8)

[Claims] 1. A chrominance data domain is mesh-divided into a plurality of blocks, a plurality of specific blocks are set as an achromatic color extraction area, and chrominance data is generated from R, G, B values of image data. For each block set as a color extraction area, the number of color difference data included in the block is counted, and the corresponding R, G, and B values are integrated, and the integrated value of the R, B, and G values for the block having the largest count value Is used for white balance adjustment of image data. 2. A color difference data domain is divided into a plurality of blocks by mesh, and a plurality of specific blocks are set as an achromatic color extraction area, and white balance control data corresponding to each of the blocks is set. Color difference data is generated from the R, G, B values of the image data obtained by the above, and the number of color difference data included in each block set as the achromatic color extraction area is counted. A white balance control method, wherein white balance control data set correspondingly is used for white balance adjustment of image data. 3. A chrominance data domain is divided into a plurality of blocks by mesh, a plurality of achromatic color extraction regions each including a group of one or more specific blocks are set, and R of image data obtained by an image sensor is set. , G, B values, and for each achromatic color extraction area, count the number of color difference data included in the achromatic color extraction area,
A white balance control method, wherein G and B values are integrated, and an integrated value of R, B and G values relating to an achromatic color extraction region having a maximum count value is used for white balance adjustment of image data. 4. A chrominance data domain is divided into a plurality of blocks by mesh, and a plurality of specific blocks are set as an achromatic color extraction area, and a chrominance difference is calculated from R, G, B values of image data obtained by an image sensor. Data is generated, and for each block set as an achromatic color extraction area, the number of color difference data included therein is counted, and the corresponding R,
The G and B values are integrated, a distribution of count values for blocks set as the achromatic color extraction area is obtained, a plurality of specific blocks are selected based on the distribution, and R, B, and R for the selected plurality of blocks are selected. A white balance control method, wherein a total value of integrated values of G values is used for white balance adjustment of image data. 5. A means for setting a specific plurality of blocks among a plurality of blocks obtained by dividing a chrominance data domain into meshes as an achromatic region, and chrominance data based on R, G, B values of image data obtained by an image sensor. Means for determining whether or not the generated color difference data is included in the block set as the achromatic color extraction area, and means for determining whether the generated color difference data is included in each block set as the achromatic color extraction area. Means for counting the number of color difference data
R, G, B corresponding to color difference data determined to be included in each block set as an achromatic color extraction area
Means for integrating values, means for selecting a specific block by comparing count values for each block set as an achromatic color extraction area, and means for integrating the R, B, and G values for the selected block. Means for adjusting the white balance of image data based on the white balance. 6. A means for setting a plurality of specific blocks in a plurality of blocks obtained by dividing a color difference data domain into meshes as an achromatic color extraction area, and white balance control data corresponding to each block set as an achromatic color extraction area. Means for generating color difference data from the R, G, and B values of image data obtained by the image sensor, and whether the generated color difference data is included in a block set as an achromatic color extraction area Means for determining whether or not each block set as an achromatic color extraction area counts the number of color difference data determined to be included in the block, and a count value for each block set as an achromatic color extraction area Means for selecting white balance control data stored corresponding to the block having the maximum count value; Means for adjusting the white balance of the image data according to the balance control data. 7. A means for setting a plurality of achromatic color extraction regions comprising a group of one or more specific blocks among a plurality of blocks obtained by dividing a chrominance data domain into meshes, and an R for image data obtained by an image sensor. , G, B values, means for determining whether the generated color data is included in the achromatic color extraction area, and means for determining whether the generated color data is included in each achromatic color extraction area. A means for counting the number of data, a means for integrating R, G, and B values corresponding to color difference data determined to be included in each achromatic color extraction area, and a count value for each achromatic color extraction area are compared with each other. Means for selecting a specific achromatic color extraction area, and means for performing white balance adjustment of image data based on an integrated value of R, B, and G values related to the selected achromatic color extraction area. A white balance control device, comprising: 8. A means for setting a plurality of specific blocks in a plurality of blocks obtained by dividing a chrominance data domain into meshes as an achromatic region, and chrominance data from R, G, B values of image data obtained by an image sensor. Means for determining whether or not the generated color difference data is included in the block set as the achromatic color extraction area, and means for determining whether the generated color difference data is included in each block set as the achromatic color extraction area. Means for counting the number of color difference data
R, G, B corresponding to color difference data determined to be included in each block set as an achromatic color extraction area
A means for integrating values, a means for taking a distribution of count values relating to blocks set as an achromatic color extraction area, and selecting a plurality of specific blocks based on the distribution; and a means R, B for selecting a plurality of blocks. , G means for calculating the total value of the integrated values, and means for adjusting the white balance of the image data based on the obtained sum value of the R, G, B values. apparatus.