The invention provides a circuit used in a padding and other processes necessary for coding of objects, and performs at high speed pixel processing to generate pixel values to be assigned to cells, using pixel values in a reference area, which includes cells with and without a pixel value. A cell address outputting unit (i) obtains cell addresses indicating positions of a predetermined number of cells serially arranged and binary signals expressing whether those cells each have a pixel value, and (ii) selects, for each cell, two of the obtained cell addresses corresponding to a part of binary signals each expressing that a cell has a pixel value, and outputs the selected cell addresses. A reading unit reads pixel values of the cells at the outputted cell addresses. An operating unit calculates the average of the two read pixel values and outputs the average as a pixel value.