IMAGE RECOGNITION METHOD BASED ON JOINT FRACTIONAL FOURIER TRANSFORMATION AND AN OPTICAL CORRELATOR FOR CARRYING OUT SAID METHOD

摘要

A studied (9) and a reference (10) images arranged on the reference plane (8) of a first optical system (2) are illuminated by two reference converging or diverging plane monochromatic waves emitted at specified equal angles with respect to an optical axis. The joint fractional Fourier transformation of images is carried out in the first single-lens or double-lens optical system (2) at the asymmetric position of the reference (8) and an exit (13) planes with respect to the lenses and satisfying the following condition: BFFT=a22b-a12Fsin υ=0, wherein a22, a12 are invariant parameters of the optical system of the joint fractional Fourier transformation; 2b is a reference distance between the initial studied (9) and the reference (10) images, F is the focal length of a lens which carries out the fractional Fourier transformation; υref is the angle of incidence of a flat monochromatic wave. The interference pattern of the joint fractional Fourier transformation at a determined spatial frequency is recorded on a photosensitive medium (12) in the exit plane (13), the Fourier transformation of said interference pattern is carried out in another optical system (3), a correlation field containing autocorrelative functions of the images which are formed in 0th diffraction order and cross-correlation images which are formed in ?1st diffraction orders being recorded.