An image processing apparatus includes a memory device and at least one processor to calculate, in a pixel block including a pixel of interest and a plurality of surrounding pixels, an absolute value of a difference in pixel value between the pixel of interest and a surrounding pixel, the calculating being performed for each of the surrounding pixels, to convert a pixel value of the surrounding pixel in accordance with the calculated absolute value, the converting being performed for each of the plurality of surrounding pixels, and to perform smoothing processing for the pixel of interest by using the plurality of surrounding pixels including the surrounding pixel whose pixel value is converted. The converting performs a combination of a pixel value of the pixel of interest and the pixel value of the surrounding pixel, so that as the calculated absolute value increases, a weight of the pixel of interest increases.