Homomorphic cameo filter for pattern recognition that is invariant with changes in illumination

We introduce a new matched filter method that yields correlation peaks that are invariant with changes in the illumination of any targets. A scene con taining objects at unknown locations is first subjected to a logarithmic tr ansformation that changes the multiplicative constant to an additive backgr ound, which is then discriminated against by means of a composite filter co ntaining a cameo of the true target and a term with which to discriminate a gainst other false targets. Experimental results are shown. (C) 2000 Optica l Society of America OCIS codes: 070.6110, 110.2970, 150.2950, 200.4740.