Implementation of a non-zero-order joint-transform correlator by use of phase-shifting techniques

The implementation of non-zero-order joint-transform correlators (JTC's) is presented. The zero-order spectra (i.e., the autocorrelation power spectral are removed from the joint-transform power spectrum by use of phase-shifting techniques bg; which the output diffraction and input spatial domain dan more efficiently be utilized. Applications of the phase-shifting techniques to both conventional JTC's and phase-transformed input STC's (PJTC's) are discussed. Compared with the conventional JTC, the PJTC has the advantages of higher light efficiency, a better signal-to-clutter ratio, and the simplicity to realize phase shifting. We anticipate that the proposed non-zero-order JTC's should have a significant impact on the future development of more efficient STC's. (C) 1997 Optical Society of America