MULTILEVEL PHASE-ENCODED AND AMPLITUDE-ENCODED MODIFIED-FILTER SYNTHETIC-DISCRIMINANT-FUNCTION FILTERS

The performance of the modified-filter synthetic-discriminant-function (MfSDF) filter with multilevel phase and amplitude (MLAP) constraints is investigated with various in-plane rotated images from an in-class Bradley armored personnel carrier vehicle and an out-of-class Abram M I tank; this is of interest because of the commercial availability of liquid-crystal televisions, which are able to encode the gray-level am plitude and/or the discrete multilevel phase information. The evaluati on is performed to explain better the image-distortion range that can be covered effectively by MLAP/MfSDF filters. The results show that th e MLAP/MfSDF filter offers much-improved correlator system performance with a greater allowable image-distortion range while maintaining 100 % discrimination between in-class and out-of-class images; furthermore , it shows an improved ability to accommodate the input image noise wh en compared with the MfSDF filter with a binary phase-only constraint. Thus the MLAP/MfSDF can be implemented effectively by a hybrid optica l/digital correlator system to track a vehicle or a tank dynamically a s it moves along a random trajectory across the input field.