Patent ID: 7706024

Claim:
An image processing apparatus that specifies a region having a registration color that is registered from a color contained in a predetermined color range in an acquired image, comprising: a hue acquiring device that receives a model image to set the registration color and acquires a hue with respect to each of pixels constituting the model image; a hue histogram calculating device that calculates a hue histogram with respect to the pixels constituting the model image, based on the hue acquired by the hue acquiring device; and a candidate color extracting device that extracts a candidate color in the predetermined color range nominated for the registration color, among the colors contained in the model image, based on the hue histogram calculated by the hue histogram calculating device, wherein the candidate color extracting device includes a hue threshold value determining device that determines a hue threshold value to define a predetermined range with respect to each candidate color, based on the hue histogram so that each of the candidate colors contains the color within the predetermined color range, wherein the hue threshold value determining device determines the hue threshold value so that the hue within the predetermined range from hue at the maximum point in the hue histogram is contained in the candidate color, wherein image processing apparatus specifies a color range with respect to the model image received by taking an image of a target object, the color range containing a registration color and colors similar to the registration color, wherein the predetermined color range is a range that includes a same color as the registration color and the colors similar to the registration color, wherein the hue threshold value includes at least a first threshold value belonging to a higher level and a second threshold value belonging to a lower level, and wherein the color range is defined with the first and second threshold values.