Contents

15 June 1973
Vol 180, Issue 4091

About The Cover

Computer processed block pictures reveal existence of two-dimensional spatial frequency analysis in vision, Block-averaged portrait at top is perceived more readily if middle and high frequencies are removed by blurring. Selective removal of high frequencies alone, as at loweer left, leads to little improvement. But selective removal only of frequencies immediately above orifinal portrait's spectrum as at lower right, is more effective. See page 1194. [L. D. Harmon and B. Julesz, Bell Laboratories, Murray Hill, New Jersey]