Figure 4.

Output of the two-stage transform is sufficient for object recognition. (A) First- and second-stage transforms for various letters. Axes and color code as in Figure 1E,F. (B) To test recognition, the transform of nine rotated and scaled versions of each letter was compared to the transform of the parent letter. The distances between the 26 parent letters (black letters) and 234 rotated and scaled versions (red dots) are approximately rendered in two dimensions by multidimensional scaling (see Materials and Methods).