Patent ID: 8306317

Claim:
An image processing apparatus that estimates a spectral characteristic of a subject from a pixel value of a subject image of the subject using an estimation operator, the image processing apparatus comprising: an exposure condition determining unit that determines a plurality of exposure conditions including a first exposure condition that is previously determined and a second exposure condition based on a pixel value of the subject image acquired under the first exposure condition; an image acquiring unit that acquires image data about a plurality of subject images of the subject picked up under the plurality of exposure conditions; a pixel value acquiring unit that acquires, as a pixel value of a pixel position to which a spectral characteristic is to be estimated, a pixel value of the image data about any one of the subject images; an estimation operator calculator that calculates the estimation operator corresponding to the exposure condition of the subject image corresponding to the image data with the pixel value acquired by the pixel value acquiring unit; and a spectral characteristic estimating unit that estimates the spectral characteristic of the subject corresponding to the pixel position to which the spectral characteristic is to be estimated using the estimation operator calculated by the estimation operator calculator; wherein the exposure condition determining unit sets, as the first exposure condition, an exposure condition of a pixel value in a predetermined pixel value range from pixel values of the subject image acquired under the first exposure condition, and determines, as the second exposure condition, an exposure condition of a pixel value outside the predetermined pixel value range; the pixel value acquiring unit includes a determining unit that determines an exposure condition of the pixel value at the pixel position for which the spectral characteristic is to be estimated in the subject image acquired under the first exposure condition; and the pixel value acquiring unit acquires the pixel value of the subject image acquired under the exposure condition determined by the determining unit.