Horizontal and Vertical rank filtering matrix

Horizontally and vertically oriented rank filters are often used to detect clusters of high density of bright edges in the area of the number plate. The width of the horizontally oriented rank filter matrix is much larger than the height of the matrix ( w≫ h ), and vice versa for the vertical rank filter ( w≪ h ). To preserve the global intensity of an image, it is necessary to each pixel be replaced with n average pixel intensity in the area covered by the rank filter matrix. In general, the convolution matrix should meet the following condition: Summation (i=0 to w-1; j=0 to h-1) mhr[i,j] = 1.

where w and h are dimensions of the matrix.

How can I designed the matrix mhr???