Abstract

A position and scale-invariant method of pattern recognition using an anamorphic Fourier correlator is presented. A modified matched filtering technique is used to obtain scale invariance. The spectrum of the scene is obtained with the nonsymmetric Fourier transform; the nonsymmetric scene spectrum matches the symmetric filter through a wedge mask. Object spectra of different sizes match the filter along different angular directions; a mask rotation search is thus substituted for a scale search. The use of a few circular harmonic filters of a target followed by a discrimination decision in feature space assures good performance. Results of a computer experiment are presented.

© 1985 Optical Society of America

Shift- and scale-invariant anamorphic Fourier correlator

Tomasz Szoplik
J. Opt. Soc. Am. A 2(9) 1419-1423 (1985)

Synthetic circular-harmonic phase-only filter for shift, rotation, and scaling-invariant correlation

Ping Zi-Liang and Erik Dalsgaard
Appl. Opt. 34(32) 7527-7531 (1995)

Shift- and scale-invariant recognition of contour objects with logarithmic radial harmonic filters

Antonio Moya, José J. Esteve-Taboada, Javier García, and Carlos Ferreira
Appl. Opt. 39(29) 5347-5352 (2000)

Real filter based on Mellin radial harmonics for scale-invariant pattern recognition

E. Tajahuerce, A. Moya, J. García, and C. Ferreira
Appl. Opt. 33(14) 3086-3093 (1994)

Shift-and-scale-invariant pattern recognition using an elliptic coordinate-transformed phase-only filter

Javier García, Tomasz Szoplik, and Carlos Ferreira
Appl. Opt. 31(23) 4823-4828 (1992)