Yezhov P. Synthesized phase objectsin the pattern recognition problem.

The thesis deals with of the pattern recognition problem. A method of synthesized phase objects is suggested. The essence of the suggested method is that synthesized phase objects are used instead of real amplitude objects. The former is the object-dependent phase distributions calculated using the iterative Fourier-transform (IFT) algorithm. The method is experimentally studied with the use of Vanderlugt optical-digital 4F-correlator. We present the comparative analysis of recognition results using conventional and proposed methods, estimate the sensitivity of the latter to distortions of the structure of objects, and determine the applicability limits. It is demonstrated that the proposed method allows one: (а) to simplify the procedure of choice of recognition signs (criteria); (b) to obtain one-type ?-like recognition signals irrespective of the type of objects; (с) to improve signal-to-noise ratio (SNR) for correlation signals by 20 - 30 dBon average. The spatial separation of the Fourier-spectra of objects and optical noises of the correlator by means of the superposition of the phase grating on recognition objects at the recording of holographic filters and at the matched filtering has additionally improved SNR (>10 dB) for correlation signals. To introduce recognition objects in the correlator, we use a spatial light modulator LC-R 2500 device. Matched filters are recorded on an original self-developing photopolymer.High efficiency of photopolymer compositions, which are used for forming of the MF was demonstrated at the matched filtering. Recording conditions of the matched filter on the photopolymer composition, which provides highest diffraction efficiency (70%) at the SNR about 40 dB for recognition objects in Vanderlugt correlator were defined. As a result of optical experiments, it is shown that the controlled variation of a recognition sensitivity at the comparison of the input and reference objects can be realized, while solving the recognition task within themethod of synthesized phase objects, as distinct from the standard approach. We have obtained and analyzed the results of the recognition for a collection of objects with the use a joint Fourier-transform correlator. To introduce joint fourier spectra in the correlator, we use a spatial light modulator LC-R HEO 1080 Pluto device. For each of the objects, we studied the character of the signal amplitude decrease depending on the growth of distortions in the object structure. We show that it is possible to obtain a family of cross-correlation curves that decrease differently within the method of synthesized phase objects, rather than a single curve. This allows one to vary the sensitivity of the correlator in the process of recognition.