Any desired diffraction pattern can be produced in the Fourier plane by specification of a corresponding input plane transparency. Complex-valued transmittance is generally required, but in practice, phase-only transmittance is used. Many design procedures use numerically intensive, constrained optimization. We, instead, use a noniterative procedure that directly translates the desired, but unavailable, complex transparency into an appropriate phase transparency. At each pixel the value of phase is pseudorandomly selected from a random distribution whose standard deviation is specified by the desired amplitude. We apply the pseudorandom phase-only encoding to hybrid composite filter design. These filters are used in a filter bank architecture to perform intensity- and distortion-invariant pattern recognition.

Date Published: 1 March 1994
PDF: 13 pages
Proc. SPIE 2237, Optical Pattern Recognition V, (1 March 1994); doi: 10.1117/12.169439

Published in SPIE Proceedings Vol. 2237:
Optical Pattern Recognition V
David P. Casasent; Tien-Hsin Chao, Editor(s)