An image reduction method and apparatus to digitize and process an image signal. Level values a to h of peripheral pixels of a pattern, the level value of a watched pixel, and the value of a reference level .THETA. are input. The level value o of the watched pixel is a gain set value .alpha., and added with the level values a to h output from the output ports of a selection circuit and supplied to a divider. The gain set value a is added with a value output from the selection circuit and supplied to the divider. The degree of signal processing is set by a .epsilon.-filter and the rate of watched pixels relating to the averaging operation is controlled and thereby, optionally setting the degree of signal processing.