Contents

09 April 1976
Vol 192, Issue 4235

About The Cover

The checkerboard is composed of edges with the same period as the coarser grating. Checkerboard fundamental Fourier components have the same period as the finer grating. The appearance of the checkerboard better matches the fine grating, suggesting that the human visual system analyzes patterns into Fourier components rather than into local features. See page 147. [Marc Green, Thomas Corwin, and Vance Zemon, Northeastern University, Boston, Massachusetts]