Dear Syan,

This problem is well known and could be solved within the scope of the socalled motion estimation algorithm among interframe. You have only to consider that your slide window corresponds to the socalled macroblock. In this process one matches every macroblock in the present frame with the macrblocks block in the search area in the previous frame.

All what you need is to divide your present frame to macroblocks say i,j where i,j is the address of the vertix pixel which is the most upper left corner of the macroblock. The macroblock size= 4x30= the size of the slide window. Every macroblock i,j will be matched with all posible macroblocks in the previous frame. According to your search method you have to compare very macroblock in the present frame with 9 macroblocks in the search area. These are the blocks having the same address as the present frame and the blocks shifted with one pixel, 2, 3 and 4 pixels upward and similarly down ward. For the matching process one calculates the sum of absolute differences between the corresponding macroblocks.

 For every macroblock in the present frame one gets 9 absolute sum of differences for the 9 microblocks to be compared in the search area.  

The sum of absolute difference SOD is a measure for the similarity between the blocks. It is so that as it decreases the similarity increases.

The number of the macroblocks in the present frame will be= 48x366/120=146.4

So, the total number of SOD= 1317.6

Best wishes