Image defects in a digital image are reduced by a process comprising:
providing a digital image data set in the form of a matrix of pixels;
selecting a sub-matrix comprising at least a 5.times.5 matrix of pixels;
identifying a pixel within the sub-matrix to be treated as a central pixel;
determining a value for at least one optical property in the central pixel;
selecting at least four pixels around the central pixel as averaging
pixels, at least two of the averaging pixels being in a position in the
sub-matrix that is not adjacent the position in the matrix of the central
pixel;
determining a value for the at least one optical property for the at least
four averaging pixels;
averaging the values for the at least one optical property for more than
one of the at least four averaging pixels to provide an average treatment
value for the central pixel;
assigning the average treatment value for the central pixel to the central
pixel; and
storing the average treatment value assigned to the central pixel.
