Disclosed is an image processing method of expanding the dynamic range by determining a saturated or noise region in an image signal and replacing the image signal with a proper image signal. A threshold value (step S4) is set in units of colors on the basis of a standard image signal for each color, which is obtained upon sensing an image in a standard exposure, and a non-standard image signal for each color, which is obtained upon sensing the image in a non-standard exposure. A saturated or noise region is determined by applying the threshold value set in units of colors to the standard image signal. A region determined as a saturated or noise region is replaced with the non-standard image signal.