Given our floor counts, we are reusing the intermediate Prewitt edges to also find the windows per floor. An approach that simply ―intersects‖ the locations along the pixel rows and columns with the maximum edge sums will work if all windows are regularly arranged. While this is often the case, it is not always true. Therefore Lee and Nevatia [50] have proposed a variation of the approach. To refine the locations of the windows a one dimensional search for the four sides of a window is performed. For every side of a window one hypothesizes a straight line segment and moves this in the two cardinal directions for a best fit with the image texture.