262931.fig.001
Figure 1: An illustration of an intensity image (a) being summed to produce an integral image (b). The sum of the elements of (a) in the dotted red box gives the corresponding element of (b). After (b) is computed, the sum of the elements of (a) in the dashed blue box, with , , can be found by using (11). In this particular example, the sum equals , while also equals .