Abstract

The classical matched spatial filter¹ (CMF) is optimum for noise but has a poor discrimination capability as it generates very broad output correlation peaks; whereas, the phase only filter² (POF) gives excellent discrimination via very sharp output correlation peaks, however, it is extremely sensitive to noise. A new adaptive filter is formulated which integrates the phase only filter with the matched spatial filter. A variable amplitude threshold value is set so that, at a particular spatial pixel location, if the amplitude value is greater than the preset threshold, ∊, only phase information is recorded; otherwise, both the phase and amplitude information are encoded. For convenience, this is called an adaptive discriminant filter (ADF). When reference images are encoded into the hybrid correlation system the amplitude threshold value is adjusted by an integrated adaptive controller to optimise noise resistance whilst maintaining discriminant ability;^3,4 Fig. 1.

© 1995 IEEE