The present invention relates to an image processing device enabling detection of a mixture ratio indicating the state of mixture between multiple objects. A contour region information generating unit 421 and a normal equation generating unit 422 extracts contour region pixel data within a frame of interest positioned at a contour region with approximately a same mixture ratio, extracts corresponding pixel data from a frame different to the frame of interest, extracting background pixel data corresponding to the contour region pixel data or the corresponding pixel data, and generating an equation wherein the mixture ratio is an unknown number, based on region specifying information specifying a non-mixed region made up of a foreground region and background region and a mixed region. A least square approximation unit 423 detects the mixture ratio by solving the equation. The present invention can be applied to signals processing devices for processing image signals.