Image processing apparatus (2) includes storage unit (14), for storing the detected value of association and the light detection position observed A kind of reference area setup unit (15) includes at least one detecting location for setting a reference area, and in the corresponding object of pixel region in image Important pixel acquisition unit (16) obtains detected value, from data, the reference area of detected value and detection position Pixel value calculation section (18) calculates the pixel value of pixel, according to acquired detected value With image forming unit (20), for pixel distribution pixel value to form image.