PROBLEM TO BE SOLVED: To provide a dynamic range expansion method capable of reducing influence of an image noise (a sesame salt noise or a random noise) and expanding a dynamic range by holding an edge part.SOLUTION: A dynamic range expansion method comprises the steps of: determining from a pixel to be processed and peripheral pixels around the pixel to be processed whether or not the pixel to be processed is a noise; multiplying a filter processing value or a non-filter processing value by a coefficient corresponding to an expansion width of a dynamic range when the pixel to be processed is a noise to calculate a dynamic range expansion pixel; and calculating the dynamic range expansion pixel from a predetermined pixel around the pixel to be processed when the pixel to be processed is not a noise.
