You see, for this problem I tried to identify each cell, one CELL would lead to other if there is no wall in between. So coordinate variable would contain each cell. Each Cell can be identified with a coordinate value, hence coordinate.

I have expained in earlier comments that, you have to identify the length and width of the cell yourself. For CELL_SIZE = 10*10, coordinate[1,1] = image[0:11,0:11].