Image sensing apparatus, white balance adjusting method, and operation processing program therefor
AssigneeCanon Kabushiki Kaisha
InventorSatoshi Nakayama
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Abstract
This invention is to provide an image sensing apparatus capable of improving white balance adjustment when an electronic flash device is used. In order to achieve this object, the image sensing apparatus has a control device for acquiring a first control value, acquiring a second control value by applying the first control value to a predetermined function, and adjusting the white balance of an image signal to be output from an image sensing device on the basis of the first and second control values.
Claims6
An image sensing apparatus, comprising:
- an electronic flash device which emits light for an object;
- a first obtaining device which obtains non-flashed gain control values for the object before light emission by said electronic flash device, wherein the non-flashed gain control values include a first color component gain and a second color component gain;
- a second obtaining device which obtains flashed gain control values for light emission by said electronic flash device, wherein the flashed gain control values include the first color components gain and the second color components gain;
- a ratio computing device which computes a ratio k (0<k<1) which represents the degree of influence of the color temperature of light to be emitted from the electronic flash device;
- a first gain computing device which computes a first gain control value for the first color component in accordance with the first color component gain of the non-flashed gain control values, the first color component gain of the flashed gain control values, and the ratio k;
- a second gain computing device which computes a second gain control value for the second color component in accordance with a black body radiation characteristic function f(x) in which the first gain control value for the first color component computed by said first gain computing device is used for x;
- and
- a control device which controls a white balance for an image of the object in accordance with the first gain control value for the first color component and the second gain control value for the second color component.
A control method for an image sensing apparatus having an electronic flash device which emits light for an object, said method comprising:
- a first obtaining step of obtaining non-flashed gain control values for the object before light emission by said electronic flash device, wherein the non-flashed gain control values include a first color component gain and a second color component gain;
- a second obtaining step of obtaining flashed gain control values for light emission by said electronic flash device, wherein the flashed gain control values include the first color components gain and the second color components gain;
- a ratio computing step of computing a ratio k (0<k<1) which represents the degree of influence of the color temperature of light to be emitted from the electronic flash device;
- a first gain computing step of computing a first gain control value for the first color component in accordance with the first color component gain of the non-flashed gain control values, the first color component gain of the flashed gain control values, and the ratio k;
- a second gain computing step of computing a second gain control value for the second color component in accordance with a black body radiation characteristic function f(x) in which the first gain control value for the first color component computed in said first gain computing step is used for x;
- and
- a control step of controlling a white balance for a image of the object in accordance with the first gain control value for the first color component and the second gain control value for the second color component.
Dependencies are inferred from the claim text.