IMAGE SCANNING AND SIGNAL PROCESSING USING SURFACE ACOUSTO-OPTIC INTERACTION

The Surface Acousto-Optic (SAO) interaction has been successfully employed in a variety of applications such as convolution, correlation, Fourier transformation in real time, and image scanning.; The theory of interaction of SAW with the coherent Gaussian beam is developed using the diffraction integral, which is eventually extended to uniform light. Two dimensional image scanning of black and white movies is performed. The system is extended to the scanning of one and two dimensional color transparencies. The modulation transfer function for the image scanner is derived and the limit of resolution is obtained from it.; The optical probing technique is employed to investigate the effect of loading the surface of the SAW substrate with a semiconductor in a separate media convolvor. Three different configurations of SAO processor, spatial integrating, time integrating, and lensless correlator, have been used to perform convolution, correlation, and Fourier transformation in real time. The performance of these correlators are compared with Silicon-on-LiNbO(,3) SAW convolver and charge coupled devices with respect to dynamic range, time bandwidth product, etc. In order to reduce the size of the SAO processor, optical fibers have been used to replace the lenses for beam shaping. The implementation of a new compact time integrating correlator using polarization discrimination technique is given.; For the first time, an incoherent source as viable alternative to the laser has been used in SAO interaction. Experimental results of autoconvolution of a pulse and image scanning of black and white and color transparencies are given using incoherent source.; A theoretical analysis of Fourier transform properties of the SAO lens, achieved by the chirp signal is developed and the experimental results are given. This active lens has been used to demultiplex the light beam of many wavelengths and to achieve electronic focusing by changing the chirp rate.; Chirp grating has been fabricated by recording the interference of a collimated beam and a cylindrically focusing beam. A new integrated acousto-optics device is suggested which employs the chirp grating as a lens (passive).; In all the experiments, the SAW substrate used is Y cut Z-propagating LiNbO(,3) and the diffraction is in the Raman-Nath region. The coherent light sources used are He-Ne and Argon-ion lasers. A projector lamp is used as an incoherent source.