Patent ID: 7957588

Claim:
An image processing apparatus that converts image signals in an input color space to image signals in an image processing space, executes a predetermined image processing with image signals in the image processing space, and then converts image signals which have undergone the predetermined image processing to image signals in an output color space, comprising: a processor for performing processing of image processing units; an offset unit that uses the processor to add an offset signal indicating a predetermined positive quantity to each of linear gradation image signals expressed as a signal in proportion to a quantity of received light at each pixel in the process of conversion from the input color space to the image processing space; a first gradation conversion unit that uses the processor to convert each of the image signals to which the offset signal has been added by the offset unit to a nonlinear gradation image signal in the image processing space; an image processing unit that uses the processor to execute the predetermined image processing with image signals corresponding to a plurality of pixels, which have undergone the gradation conversion by the first gradation conversion unit; and a second gradation conversion unit that uses the processor to convert image signals which have undergone the image processing by the image processing unit to linear gradation image signals in the process of conversion to the output color space, wherein the image processing unit converts a first image to a second image by using the image signals corresponding to a plurality of pixels, which have undergone the gradation conversion by the first gradation conversion unit, and the second gradation conversion unit executes inverse conversion to inversely convert each of signals constituting the second image to the linear gradation image signal, and executes conversion to output image signals in the output color space by using image signals obtained by subtracting the offset signal indicating the predetermined positive quantity from each of the image signals having undergone the inverse gradation conversion.