JP2006148486A - Imaging apparatus and white balance control value calculation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately perform the white balance correction of a region irradiated by a dimmer, in a light-controlled and photographed image. <P>SOLUTION: This apparatus has a stroboscope (130) which outputs information representing a lighting angle of irradiating light; a lens (120) for outputting information representing a focal length; an imaging device (101) which converts an optical image of an object impinged through a lens into an electrical signal and outputs image data; a search region table (140) which determines at least a part of a region where light control by the stroboscope is performed inside the angle of the field of the lens on the basis of the irradiating angle and the focal length, and determines the determined region as a data search region for data used for the white balance correction of data on images picked up by the imaging device while performing light control by the stroboscope; and a calculation means (112, 114) for detecting a colorless part in the search region from the image data, and computing a white balance control value on the basis of partial image data corresponding to the colorless part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device and a white balance control value calculation method, and more particularly, to a white balance control value calculation method in the case of shooting with light control and an imaging device to which the method is applied.

  FIG. 9 is a diagram illustrating a configuration example of a conventional digital camera.

  In FIG. 9, a subject optical image that has passed through a photographing lens (not shown) forms an image on the image sensor 301 and is converted into a charge corresponding to the amount of light. The image sensor 301 is covered with, for example, R (red), G (green), and B (blue) color filters as shown in FIG. Note that the filter array shown in FIG. 10 is generally called a Bayer array, and is configured as a set of four pixels in which two G filters each having a high contribution to the luminance signal are arranged. In the process described later, considering the case where a readout amplifier is used in which the row including R and the row including B are different due to the circuit configuration of the image sensor, G in R row is set to G1, and G in B row is set to G1. Since G1 and G2 are handled as different color components as G2, they are described separately in FIG. Each color filter has a spectral sensitivity around the wavelength band of each color, and a photoelectric conversion element provided corresponding to each color filter photoelectrically converts light in the band that has passed through each color filter.

  The electric charge converted by each photoelectric conversion element is output as an electric signal from the image pickup element 301 to the A / D conversion unit 303 and converted into a digital signal (image data) by A / D conversion processing.

  The digital signal output from the A / D conversion unit 303 is sent to the auto white balance (AWB) processing unit 305 for gain correction, and simultaneously sent to the chromaticity coordinate conversion unit 310.

  In the case of auto white balance that automatically obtains a white balance control value suitable for a photographed image from photographed image data, for example, a white balance gain value (white balance control value) is obtained as follows.

First, the chromaticity coordinate conversion unit 310 obtains R: B and (R + B) :( G1 + G2) by combining the adjacent R, G1, G2, and B in the image data as shown in FIG. , Plotted on two-dimensional coordinates as shown in FIG. 11, the achromatic color portion detection unit 312 determines the combination of R, G1, G2, and B located within the frame of the coordinate range 801 in the vicinity of the blackbody radiation locus 802. It is determined as an achromatic region. Then, the WB gain calculation unit 314 sequentially integrates the determined combination signal for each color component to obtain integration values SumR, SumG1, SumG2, and SumB of each color component, and the ratio of SumR: SumG1: SumG2: SumB is G. The white balance control values WbR, WbG1, WbG2, and WbB, which are 1: 1: 1: 1, are determined as shown in the following equation (1) with reference to the components.
WbR = (SumG1 + SumG2) / (2 x SumR)
WbG1 = (SumG1 + SumG2) / (2 x SumG1)
WbG2 = (SumG1 + SumG2) / (2 x SumG2)
WbB = (SumG1 + SumG2) / (2 × SumB) (1)

  The AWB processing unit 305 determines that the white balance control value obtained as described above in the WB gain calculation unit 314 is a control value for the optimum color temperature of the light source in this image, and out of all the image data. By multiplying WbR for the pixel signal of the R filter, WbG1 for the pixel signal of the G1 filter, WbG2 for the pixel signal of the G2 filter, and WbB for the pixel signal of the B filter, respectively. Perform balance calculation processing.

  The image data that has been subjected to auto white balance processing is developed in the development processing unit 307. Here, white balance adjusted image data is optimized for output for monitor viewing and print output by giving optimal contrast characteristics with optimal gamma characteristics, color adjustment, sharpness processing, etc. It is converted into image data with characteristics.

  The image data that has been subjected to image processing that is optimal for output by the development processing unit 307 is output as a file in the image data output unit 309. For example, when converting the file format to a JPEG file, the image-processed RGB data is converted into the YCrCb format by three-dimensional matrix conversion and attached data is attached to convert the data into the JPEG file format (see, for example, Patent Document 1). ).

JP 07-154814 A

  In the above conventional example, when auto white balance processing is performed, an achromatic color portion is detected from all captured image data, and a gain for making R: G: B of the detected portion 1: 1: 1 is obtained, This is realized by multiplying the gain for each of the R, G, and B color components.

  As shown in FIG. 12, when taking a picture with a light control device such as a strobe attached to a camera that performs white balance processing according to the above method, particularly when the taking lens is a wide-angle lens with a short focal length, as shown in FIG. The shooting angle of view B may be wider than the widest angle A of the irradiation angle of the apparatus.

  For example, in the imaging surface 403 at the position of the subject 402 in FIG. 12, when irradiation with a strobe is performed, as shown in FIG. 2A, a portion 502 irradiated with the strobe and a peripheral portion 503 that is not irradiated are generated. To do. In such a shooting screen 501, when the light source that originally illuminates the subject 402 and its surroundings as steady light is a light source with strong redness such as tungsten light or halogen light, the color temperature is about 3000K. The bluish strobe light with a temperature of about 5500K is significantly different from the light source color. In such a photographing screen 501, in order to detect an achromatic color part for obtaining a white balance control value from an image portion 503 with strong redness that is not dimmed by the conventional method described above, the low color temperature with strong redness is detected. The achromatic part on the side also affects the result of white balance. As a result, the white balance correction 502 on the high color temperature side, which is being dimmed, cannot be properly corrected for white balance, resulting in a correction result in which some blueness remains, resulting in an unsightly image.

  The present invention has been made in view of the above problems, and an object of the present invention is to appropriately perform white balance correction of an area irradiated by a light control device in an image photographed with light control. .

  In order to achieve the above object, an imaging apparatus according to the present invention converts an object optical image incident through a lens unit into an electrical signal and outputs image data, and information indicating an irradiation angle of a light control unit. And a calculation means for calculating a white balance control value from the image data including the light control area adjusted by the light control means based on the information indicating the focal length of the lens unit, and the calculation means Calculates the white balance control value so as to suppress the influence of the image data outside the light control area.

  The white balance control value calculation method according to the present invention includes an imaging step of converting an object optical image incident through the lens unit into an electrical signal and outputting image data, information indicating an irradiation angle of the light control means, A calculation step of calculating a white balance control value from the image data including the dimming area dimmed by the dimming unit based on information indicating a focal length of the lens unit, and in the calculation step, A white balance control value is calculated so as to suppress the influence of image data outside the light control region.

  According to another configuration, the imaging apparatus of the present invention includes a dimming unit that outputs information indicating an irradiation angle of light to be irradiated, a lens unit that outputs information indicating a focal length, and the lens unit. The lens unit based on the imaging unit that converts the incident optical image of the subject into an electrical signal and outputs image data, the irradiation angle output from the dimming unit, and the focal length output from the lens unit Of the image data of the image data captured by the imaging unit by performing light control by the light control unit. A search area determining means for determining a search area for image data used for white balance correction, and detecting an achromatic portion in the search area from the image data, and based on partial image data corresponding to the achromatic portion , And a calculating means for calculating a white balance control value.

  Further, the white balance control value calculation method of the present invention includes an information acquisition step of acquiring information indicating an irradiation angle of light irradiated by the dimming unit and information indicating a focal length of the lens unit, and the lens unit. Based on the imaging step of converting the incident optical image of the subject into an electrical signal and outputting image data, and the irradiation angle and focal length acquired in the information acquisition step, Determine at least a part of the area dimmed by the dimming means, and use the determined area for white balance correction in the image data captured in the imaging step by performing dimming by the dimming means. A search region determination step for determining a search region for image data; and detecting an achromatic color portion in the search region from the image data; and performing a whit based on the partial image data corresponding to the achromatic color portion. And a calculation step of calculating the balance control value.

  Further, according to another configuration, a dimming unit that outputs information indicating an irradiation angle of light to be irradiated, a lens unit that outputs information indicating a focal length, and a subject optical image incident through the lens unit Imaging means for converting to electrical signals and outputting image data, dividing the image data into a plurality of regions, based on the irradiation angle output from the dimming means and the focal length output from the lens unit, Weighting coefficient determining means for assigning a weighting coefficient to each of the plurality of divided areas so that the weight of the area dimmed by the dimming means is larger than the weight of the area not dimmed, and the image data Achromatic portions are detected for each of the plurality of divided regions, and the partial image data corresponding to the detected achromatic portions are assigned to the divided regions to which the achromatic portions belong. Weighted by viewing with coefficients, and a calculating means for calculating a white balance control value based on the obtained value.

  According to another configuration, the white balance control value calculation method according to the present invention includes an information acquisition step of acquiring information indicating an irradiation angle of light irradiated by the dimming unit and information indicating a focal length of the lens unit. An imaging process for converting the optical image of the subject incident through the lens unit into an electrical signal and outputting image data; and the irradiation angle obtained by dividing the image data into a plurality of regions and acquired in the information acquisition process And assigning a weighting coefficient to each of the plurality of divided areas so that the weight of the area dimmed by the dimming means is larger than the weight of the non-dimmed area A weighting coefficient determining step, detecting achromatic portions for each of the plurality of divided regions of the image data, and for each of the achromatic portions for the partial image data corresponding to each detected achromatic portion Weighted by weighting coefficient is assigned to belong divided regions, based on the obtained value and a calculation step of calculating the white balance control value.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform appropriately the white balance correction | amendment of the area | region irradiated with the light control apparatus in the image image | photographed by light control.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

<First Embodiment>
A first embodiment of the present invention will be described.

  FIG. 1 is a block diagram illustrating a schematic functional configuration of an imaging apparatus such as a digital camera according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 120 denotes a photographing lens unit including a zoom lens and a focus adjustment lens, and 101 denotes a subject optical image transmitted through the photographing lens unit 120 and outputs an electrical signal corresponding to the received light amount. Here, it is assumed that the image sensor is covered with a so-called Bayer array color filter shown in FIG. Reference numeral 103 denotes an A / D converter that converts an electrical signal output from the image sensor into a digital signal (image data). Reference numeral 105 denotes an auto that performs white balance processing on the image data output from the A / D converter 103. A white balance (AWB) processing unit 107, a development processing unit 107 that performs development processing on image data that has been subjected to white balance processing by the AWB processing unit 105, and 109 outputs image data generated by the development processing as an image file. An image data output unit. In addition, each said structure performs the processing operation similar to the past.

  The image data output from the A / D conversion unit 103 is also output to the chromaticity coordinate conversion unit 110. The chromaticity coordinate conversion unit 110 converts the input image data into two-dimensional coordinates as shown in FIG. 11, and the achromatic color part detection unit 112 converts the achromatic color image data (R within the frame of the coordinate range 801). , G1, G2, B), image data in a search area to be described later is detected. The WB gain calculation unit 114 calculates white balance (AWB) control values WbR, WbG1, WbG2, and WbB used for white balance processing based on the achromatic color image data detected by the achromatic color part detection unit 112. Using the calculated AWB control value, the AWB processing unit 105 performs AWB processing.

  The photographing lens unit 120 outputs a focal length information output unit 121 that outputs focal length information of a zoom lens (not shown), and lens hood mounting information that indicates a mounting state of a light shielding lens hood that is mounted on the photographing lens unit 120. And a lens hood mounting information output unit 123.

  Further, reference numeral 130 denotes a strobe as a light control device, which outputs an operation signal output unit 131 for outputting an operation signal indicating that the light is emitted from the strobe 130 to perform light control photographing, and outputs irradiation angle characteristic information of the strobe 130. An irradiation angle characteristic output unit 133 and an irradiation direction information output unit 135 that outputs irradiation direction information of the strobe 130 are included.

  The above-described focal length information and lens hood mounting information output from the photographing lens unit 120, and irradiation angle characteristic information and irradiation direction information output from the strobe 130 are search areas for specifying an image area used for calculating the AWB control value. A search area for outputting the achromatic color image data is determined by the achromatic color portion detection processing unit 112, which is output to the table 140. The information of the search area determined in the search area table 140 is sent to the dimming differential detection unit 142, and when a differential information signal indicating dimming shooting by the strobe 130 is input from the operation signal output unit 131, It is sent to the achromatic color part detection unit 112.

  When the information on the search area is sent from the dimming differential detection unit 142, the achromatic color part detection unit 112 detects the achromatic color part of the image in the search area as in the conventional example, and the image The color component signals R, G1, G2, and B of the data are sent to the WB gain calculation unit 114. The WB gain calculation unit 114 calculates the AWB correction value using the integrated values SumR, SumGr1, SumGr2, and SumB of the respective color component signals R, G1, G2, and B, which are detection results.

  Next, the search area determination operation in the search area table 140 according to the first embodiment of the present invention will be described in detail.

  For example, when the shooting field angle corresponding to the focal length of the shooting lens unit 120 is the angle B in FIG. 12 and the widest angle of the irradiation angle of the strobe 130 is the angle A in FIG. 12, the position of the subject 402 in FIG. When irradiation with the strobe 130 is performed on the imaging surface 403, as shown in FIG. 2A, a portion 502 irradiated with the strobe 130 and a peripheral portion 503 not irradiated are generated in the photographing screen 501. The portion 502 irradiated by the strobe 130 is determined by the shooting field angle B and the widest angle A. Therefore, the search area table 140 searches the strobe 130 for an achromatic portion of the image based on the focal length information corresponding to the shooting angle of view B and the irradiation angle characteristic information of the strobe 130 corresponding to the widest angle A. 2 is determined to be the region 505 in FIG. 2B inside the portion 502 irradiated, and the search region information is output.

  When the strobe 130 is used when a shooting operation is performed under these conditions, the dimming operation signal detector 142 receives the operation signal of the strobe 130, and the search area information is achromatic in synchronization with the differential signal. The data is output to the detection unit 112.

  In the first embodiment, an area irradiated by the strobe 130 is measured in advance with different combinations of the focal length of the photographing lens 120 and the irradiation angle characteristic of the strobe 130, and represents a rectangle inscribed in the area. Coordinates are given as search area information. For example, as shown in FIG. 2B, the coordinates of the upper left corner of the screen are (0, 0), the coordinates of the lower right corner are (Xt, Yt), and the search start position of the achromatic portion in the screen. Is (Xs, Ys), and the search end position is (Xe, Ye). The coordinates of these two points are sent to the achromatic color detection unit 112, and a process of detecting the image data of the achromatic color portion is performed in the area 505 represented by these two points, that is, the search area.

  In addition, when a light-shielding lens hood is attached to the photographing lens unit 120, a photographed image using the strobe 130 has a portion 706 where the strobe light from the lens hood is vignetted as shown in FIG. appear. In this case, the search area is determined based on the combination of the focal length information and lens hood mounting information of the photographing lens unit 120 and the irradiation angle characteristic information of the strobe 130.

Similar to FIG. 2B, when the search area is represented by coordinates indicating the position in the screen 701, the search start position of the achromatic portion in the screen is set to (Xs, Ys) as shown in FIG. The search end position is set to (Xe, Ye), and a search is made for the achromatic portion in the range 705 excluding the shaded portion 707 represented by the vignetting range (Xfs, Yfs) and (Xfe, Yfe) of the lens hood. This is an area. That is, the search area 705 is a range represented by the following (5), (6), and (7).
Xs ≤ X ≤ Xe and Ys ≤ Y ≤ Yfs (5)
Xs ≤ X ≤ Xfs and Yfs ≤ Y ≤ Ye (6)
Xfe ≤ X ≤ Xe and Yfs ≤ Y ≤ Ye (7)

In this way, the coordinates (Xs, Ys), (Xe, Ye), (Xfs, Yfs), (Xfe, Yfe) of the four points are sent to the achromatic color detecting unit 112, and the search area 705 represented by these four points. The detection process of the achromatic part is performed.
In addition, when the irradiation center position of the strobe 130 is moved, search area information for detecting an achromatic portion of the image includes focal length information of the photographing lens unit 120, lens hood attachment information, and irradiation angle characteristic information of the strobe 130. In addition, the search area is determined based on the combination with the irradiation direction information of the strobe 130.

As in FIG. 2B, the case where the search area is represented by coordinates indicating the position in the screen 901 will be described with reference to FIG. When the strobe irradiation center coordinates in the screen move from the screen center coordinates (Xc, Yc) to (Xc ', Yc'), the search start position (Xs, Ys) and search end position ( Xe, Ye) becomes (Xs− (Xc−Xc ′), Ys− (Yc−Yc ′)), (Xe− (Xc−Xc ′), Ye− (Yc−Yc ′)). However, when the coordinate value becomes minus (−), it is set to 0, and when the coordinate value exceeds the maximum values Xt and Yt, it is set to the maximum value. When the strobe illumination center is shifted horizontally to the left as in the example shown in FIG. 4 and there is vignetting due to the lens hood, the range (Xfs) of the vignetting portion 907 is determined from the range given by the shifted search start position and search end position. , Yfs) and a range 905 excluding the hatched portion 907 represented by (Xfe, Yfe) is set as a search region for the achromatic portion. That is, the search area 905 is a range represented by the following (8) and (9).
0 ≦ X ≦ Xe− (Xc−Xc ′) and Ys ≦ Y ≦ Yfs (8)
0 ≤ X ≤ Xfs and Yfs ≤ Y ≤ Ye (9)

The coordinates of these four points (Xs− (Xc−Xc ′), Ys− (Yc−Yc ′)), (Xe− (Xc−Xc ′), Ye− (Yc−Yc ′)), (Xfs, Yfs) , (Xfe, Yfe) are sent to the achromatic color detection unit 112, and the achromatic color portion is detected in the search area 905 represented by these four points.
As described above, according to the first embodiment, in order to obtain the control value of the auto white balance, the search area when detecting the achromatic portion from the image data in the screen is adjusted with the information of the photographing lens. By using the information of the optical device, the shooting angle of view of the taking lens exceeds the illumination angle of the dimmer, or it is affected by the part that is not dimmed by vignetting by the lens hood of the taking lens. The image data of the part that is not dimmed that is generated in the above can be excluded from the search area. As a result, it is possible to obtain an appropriate white balance control value for the light control area without being affected by the image data of the non-light control portion, and the white area of the area irradiated by the light control device can be obtained. It becomes possible to perform balance correction appropriately.

  In the first embodiment, the search area is a single or a plurality of rectangles represented by the coordinates of the start point and the end point. However, the search region is represented by a polygon other than a rectangle, a circle, an ellipse, or the like. Also good.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.

  FIG. 5 is a block diagram showing a schematic functional configuration of an imaging apparatus such as a digital camera according to the second embodiment of the present invention.

  In FIG. 5, the same components as those in FIG. 5 is different from FIG. 1 in that a search area weighting table 240 is used instead of the search area table 140 for determining the search area in FIG. 1 and that a detection area weighting unit 246 is further provided. Further, the operation of the achromatic color part detection unit 212 is different from the operation of the first embodiment.

  In the following, portions different from the first embodiment will be described mainly.

  The achromatic color part detection unit 212 performs processing for detecting achromatic image data from the chromaticity coordinate signal converted by the chromaticity coordinate conversion unit 110 for each search area block divided into a plurality of parts in the screen. The area weighting unit 246 integrates the achromatic image data obtained for each search area block for each color component, and performs weighting processing on the integrated values SumR, SumGr1, SumGr2, and SumB. The white balance gain calculation unit 114 adds the integral values for each color component weighted for each detection area block in this way for all the search area blocks, and based on the calculated total value, the same as in the conventional case. The AWB control value is calculated by this method.

  Next, the weighting determination operation in the search area weighting table 240 according to the second embodiment of the present invention will be described in detail.

  The search area weighting table 240 includes lens focal length information output from the focal length information output unit 121, lens hood mounting information output from the lens hood mounting information output unit 123, and irradiation output from the irradiation angle characteristic output unit 133. Based on the angular characteristic information and the irradiation direction information output from the irradiation direction information output unit 135, a weighting coefficient is determined for each search area block obtained by dividing the screen. The weighting coefficient determined by the weighting table 240 is sent to the dimming differential detection unit 142, and when a differential information signal indicating dimming shooting by the strobe 130 is input from the operation signal output unit 131, a detection area weighting unit 246.

  In FIG. 6, the field angle of view corresponding to the focal length of the photographing lens is B in FIG. 12, and the widest angle at which the strobe 130 mounted on the imaging device such as a digital camera for photographing can be dimmed is the angle A in FIG. It is a figure explaining the weighting coefficient at the time of being. In the shooting screen 1001 of FIG. 6A, the portion 1002 irradiated by the strobe 130 is determined by the shooting field angle B and the widest angle A. Therefore, in the search area weighting table 240, the lens corresponding to the shooting field angle B is displayed. Based on the focal length information and the irradiation angle characteristic information of the strobe 130 corresponding to the widest angle A, for example, a weighting coefficient for multiplying the integral value for each color component obtained from each search area block is shown in FIG. And then output to the dimming operation signal detector 142.

  When the strobe 130 is used when a photographing operation is performed under these conditions, the operation signal of the strobe 130 is received by the dimming operation signal detection unit 142, and the weighting coefficient is searched for in the search area weighting unit 246 in synchronization with the signal. Output to.

  In the second embodiment, the weighting coefficient is a combination of the focal length information of the photographing lens unit 120 and the irradiation angle characteristic information of the strobe 130, and the area irradiated by the strobe 130 is measured in advance. It is determined according to the characteristics of the irradiation state. For example, as shown in FIG. 6B, for each search area block, “× 1.0” is used for a block that includes the entire dimmable range, and a block that partially includes the dimmable range. The weighting coefficient is determined in advance such as “× 0.4”, “× 0.5”, “× 0.6”, etc. depending on the area ratio. A weighting coefficient of “× 0” is given to a block that does not include the dimmable range at all.

  When a lens hood for light shielding is attached to the photographic lens unit 120, as shown in FIG. 7A, a photographed image using the strobe 130 has a portion 1206 where stroboscopic light from the lens hood is vignetted. . In this case, the weighting coefficient is determined based on the combination of the focal length information and lens hood mounting information of the photographing lens unit 120 and the irradiation angle characteristic information of the strobe 130.

  For example, as shown in FIG. 7B, the weighting coefficient for the search area blocks 1301 and 1302 where vignetting occurs due to the lens hood corresponding to the area 1206 in FIG. 7A is multiplied by “× 0”. Also in the peripheral blocks, different weighting coefficients are given according to the degree of vignetting.

  When the irradiation center position of the strobe 130 is moved, the weighting coefficient for each search area block is added to the focal length information and lens hood mounting information of the photographing lens unit 120 and the irradiation angle characteristic information of the strobe 130, and further, the strobe 130. The weighting coefficient is determined based on the combination with the irradiation direction information.

  For example, as shown in FIG. 8A, when the irradiation center position of the strobe 130 is horizontally shifted to the left and shifted from the screen center 1408 to 1409, and there is vignetting due to the lens hood, each search area block in the screen The weighting coefficient to be multiplied by is determined, for example, as shown in FIG. Similarly to the example shown in FIG. 7B, the weighting coefficient to be applied to the block at the position corresponding to the vignetting area 1406 by the lens hood is set to “× 0” times.

  As described above, according to the second embodiment, each search area obtained by dividing the screen into a plurality of areas when detecting the achromatic color portion from the image data in the screen in order to obtain the control value of auto white balance. By determining the weighting coefficient for the block using the information on the photographic lens and the information on the dimmer, the shooting angle of view of the photographic lens exceeds the irradiation angle of the dimmer, or depending on the lens hood of the photographic lens. Since the influence of the non-dimmed part of the image data that occurs due to the influence of the part that is not dimmed by vignetting can be reduced according to the stage, obtain a more appropriate white balance control value Thus, it is possible to appropriately perform white balance correction on the region irradiated by the light control device.

  In the first and second embodiments, the case where the photographing lens unit 120 and the strobe 130 are configured integrally with the imaging device has been described. However, the configuration may be detachable.

  The photographing lens unit 120 has been described as having a zoom lens, but it goes without saying that it may be a single focus lens.

  In the first embodiment, the white balance control value is finally calculated by the WB gain calculation unit using the search region table 140. In the second embodiment, the search region weighting table 240, the search region weighting unit 246, the white balance control value is finally calculated by the WB gain calculation unit. However, the present invention is not limited thereto, and the image data corresponding to the area dimmed by the dimming device when the gain calculation unit finally calculates the white balance control value based on the image data obtained from the image sensor 101. Any other method may be used as long as the gain calculation unit finally calculates the white balance control value based on the image data in which the influence of the other region is suppressed.

<Other embodiments>
Note that the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, and a camera head) or to a device composed of a single device (for example, a digital still camera). Good.

  Another object of the present invention is to supply a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or Needless to say, this can also be achieved by the MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included. Examples of the storage medium for storing the program code include a flexible disk, hard disk, ROM, RAM, magnetic tape, nonvolatile memory card, CD-ROM, CD-R, DVD, optical disk, magneto-optical disk, MO, and the like. Can be considered. Also, a computer network such as a LAN (Local Area Network) or a WAN (Wide Area Network) can be used to supply the program code.

  Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is based on the instruction of the program code. It goes without saying that the CPU or the like provided in the expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

1 is a block diagram illustrating a schematic functional configuration of an imaging apparatus according to a first embodiment of the present invention. It is a figure explaining the detection area | region in the 1st Embodiment of this invention. It is a figure explaining the detection area | region in the 1st Embodiment of this invention. It is a figure explaining the detection area | region in the 1st Embodiment of this invention. It is a block diagram which shows schematic function structure of the imaging device in the 2nd Embodiment of this invention. It is a figure explaining the weighting coefficient in the 2nd Embodiment of this invention. It is a figure explaining the weighting coefficient in the 2nd Embodiment of this invention. It is a figure explaining the weighting coefficient in the 2nd Embodiment of this invention. It is a block diagram which shows the function structure of the conventional imaging device. It is a figure which shows an example of the combination of the pixel when calculating the position of the color filter on an image sensor, and chromaticity coordinates. It is a figure showing the black body radiation locus | trajectory on a chromaticity coordinate, and an achromatic color determination area | region. It is a figure which shows the relationship between an imaging | photography field angle and the widest angle of the irradiation angle of a light modulation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Image pick-up element 103 A / D conversion part 105 Auto white balance calculation part 107 Development processing part 109 Image data output part 110 Chromaticity coordinate conversion part 112,212 Achromatic part detection part 114 White balance gain calculation part 120 Shooting lens part 121 Focus Distance information output unit 123 Lens hood mounting information output unit 130 Light control device 131 Operation signal output unit 133 Irradiation angle characteristic output unit 135 Irradiation direction information output unit 140 Search region table 142 Light control operation detection unit 240 Search region weighting table 246 Search region Weighting section

Claims (26)

Imaging means for converting a subject optical image incident via the lens unit into an electrical signal and outputting image data;
Calculation for calculating a white balance control value from the image data including the light control region adjusted by the light control unit based on the information indicating the irradiation angle of the light control unit and the information indicating the focal length of the lens unit. Means,
The image pickup apparatus, wherein the calculating means calculates a white balance control value so as to suppress an influence of image data other than the light control region. An imaging step of converting an optical image of an object incident through the lens unit into an electrical signal and outputting image data;
Calculation for calculating a white balance control value from the image data including the light control region adjusted by the light control unit based on the information indicating the irradiation angle of the light control unit and the information indicating the focal length of the lens unit. A process,
In the calculation step, a white balance control value is calculated so as to suppress an influence of image data other than the light control region, and a white balance control value calculation method is characterized. Dimming means for outputting information indicating the irradiation angle of the light to be irradiated;
A lens unit that outputs information indicating the focal length;
Imaging means for converting a subject optical image incident through the lens unit into an electrical signal and outputting image data;
Based on the irradiation angle output from the dimming means and the focal length output from the lens unit, at least a part of the area dimmed by the dimming unit is determined from the angle of view of the lens unit. Search area determining means for determining the determined area as a search area for image data used for white balance correction among the image data imaged by the imaging means by performing light control by the light adjustment means;
An image pickup apparatus comprising: a calculating unit that detects an achromatic color portion in the search area from the image data and calculates a white balance control value based on the partial image data corresponding to the achromatic color portion. . The light control means further outputs information indicating the irradiation direction of the light to be irradiated,
The said search area | region determination means further judges at least one part of the area | region dimmed by the said light control means based on the irradiation direction output from the said light control means. Imaging device. The lens unit further outputs lens hood mounting information indicating whether or not a lens hood is mounted on the lens unit,
5. The search area determination unit further determines at least a part of a region dimmed by the dimming unit based on lens hood mounting information output from the lens unit. The imaging device described in 1.   The imaging apparatus according to claim 3, wherein the search area determination unit expresses the search area by coordinates.   The search area determining means associates in advance the irradiation angle of the dimming means, the focal length of the lens unit, and the search area indicating at least a part of the area dimmed by the dimming means. The imaging apparatus according to claim 3, further comprising a stored table unit.   The calculation means sums the partial image data corresponding to the achromatic color portion detected in the detection area for each color, and calculates a coefficient with which the obtained sum for each color has the same ratio as a white balance control value. The image pickup apparatus according to claim 3, wherein the image pickup apparatus is an image pickup apparatus. Dimming means for outputting information indicating the irradiation angle of the light to be irradiated;
A lens unit that outputs information indicating the focal length;
Imaging means for converting a subject optical image incident through the lens unit into an electrical signal and outputting image data;
The image data is divided into a plurality of areas, and the weight of the area dimmed by the dimming means is dimmed based on the irradiation angle output from the dimming means and the focal length output from the lens unit. Weighting coefficient determining means for assigning a weighting coefficient to each of the plurality of divided areas so as to be larger than the weight of the area that has not been performed;
A weighted coefficient assigned to the divided area to which each achromatic color part belongs to the partial image data corresponding to each detected achromatic color part for each of the plurality of divided areas of the image data. An image pickup apparatus comprising: a calculation unit that performs weighting by calculating a white balance control value based on the obtained value. The light control means further outputs information indicating the irradiation direction of the light to be irradiated,
The imaging apparatus according to claim 9, wherein the weighting coefficient determination unit further assigns a weighting coefficient based on the irradiation direction output from the light control unit. The lens unit further outputs lens hood mounting information indicating whether or not a lens hood is mounted on the lens unit,
The imaging apparatus according to claim 9 or 10, wherein the weighting coefficient determination unit further assigns a weighting coefficient based on lens hood mounting information output from the lens unit.   12. The calculating means according to claim 9, wherein the weighted partial image data is summed for each color, and a coefficient with which the obtained sum for each color has the same ratio is calculated as a white balance control value. The imaging device according to any one of the above.   The imaging apparatus according to claim 3, further comprising a white balance processing unit that performs white balance correction using the white balance control value calculated by the calculation unit. An information acquisition step of acquiring information indicating an irradiation angle of light emitted by the light control means and information indicating a focal length of the lens unit;
An imaging step of converting an optical image of a subject incident through the lens unit into an electrical signal and outputting image data;
Based on the irradiation angle and the focal length acquired in the information acquisition step, determine at least a part of the area dimmed by the dimming means in the angle of view of the lens unit, and determine the determined area. A search area determination step for determining a search area for image data to be used for white balance correction among the image data captured in the imaging step by performing light control by the light control means;
A white balance, comprising: a white balance control value is detected based on partial image data corresponding to the achromatic color portion detected from the image data in the search region. Control value calculation method. In the information acquisition step, further acquiring information indicating the irradiation direction of the light irradiated by the light control means,
15. The white balance control value calculation method according to claim 14, wherein in the search area determination step, at least a part of the area dimmed by the dimming unit is further determined based on the irradiation direction. In the information acquisition step, further acquiring lens hood mounting information indicating whether or not a lens hood is mounted on the lens unit,
16. The white balance control according to claim 14 or 15, wherein the search area determination step further determines at least a part of an area dimmed by the dimming means based on the lens hood mounting information. Value calculation method.   The white balance control value calculation method according to claim 14, wherein in the search area determination step, the search area is expressed by coordinates.   In the search area determining step, the irradiation angle of the light control means, the focal length of the lens unit, and the search area indicating at least a part of the area adjusted by the light control means are associated with each other in advance. 15. The white balance control value calculation method according to claim 14, wherein the search area used by the calculation unit is determined with reference to a stored table unit.   In the calculation step, the partial image data corresponding to the achromatic color portion detected in the detection region is summed for each color, and a coefficient with which the obtained sum for each color has the same ratio is calculated as a white balance control value. The white balance control value calculation method according to claim 14, wherein the white balance control value is calculated. An information acquisition step of acquiring information indicating an irradiation angle of light irradiated by the light control means and information indicating a focal length of the lens unit;
An imaging step of converting an optical object image incident through the lens unit into an electrical signal and outputting image data;
The image data is divided into a plurality of regions, and based on the irradiation angle and the focal length acquired in the information acquisition step, the weight of the region dimmed by the dimming unit is not dimmed A weighting factor determination step of assigning a weighting factor to each of the plurality of divided regions so as to be larger than the weight;
A weighted coefficient assigned to the divided area to which each achromatic color part belongs to the partial image data corresponding to each detected achromatic color part for each of the plurality of divided areas of the image data. And calculating a white balance control value based on the obtained value. A white balance control value calculation method comprising: In the information acquisition step, further output information indicating the irradiation direction of the light irradiated by the light control means,
21. The white balance control value calculation method according to claim 20, wherein the weighting coefficient determination step further assigns a weighting coefficient based on the irradiation direction. In the information acquisition step, further acquiring lens hood mounting information indicating whether or not a lens hood is mounted on the lens unit,
The white balance control value calculation method according to claim 20 or 21, wherein the weighting coefficient determination step further assigns a weighting coefficient based on the lens hood mounting information.   23. The calculation step according to claim 20, wherein the weighted partial image data is summed for each color, and a coefficient with which the obtained sum for each color has the same ratio is calculated as a white balance control value. The white balance control value calculation method according to any one of the above.   The white balance control value calculation method according to any one of claims 14 to 23, further comprising a white balance processing step of performing white balance correction using the white balance control value calculated by the calculation step.   25. A program executable by an information processing apparatus, comprising program code for realizing the white balance control value calculation method according to claim 14.   26. A storage medium readable by an information processing apparatus, wherein the program according to claim 25 is stored.

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