Growth and characterization of l-leucine l-leucinium picrate single crystal: A new nonlinear optical material

This paper concerns the problem of the optimization of parameters in acousto-optic image processing systems. The optimization was carried out with the purpose of obtaining the best performance and minimum driving power. A choice of optimal geometry of acousto-optic interaction in the crystal is discussed. Longitudinal aberrations in the device caused by dispersion of refractive indices of acousto-optic media are studied. Calculations prove that a specific choice of distances between optical elements in the device can reduce the aberration to a value less than the focal depth of a filtered image. Spectral analysis of radiation reflected from artificial test objects demonstrates operationaal capability of the imager.

http://iopscience.iop.org/article/10.1088/1464-4258/9/4/006/pdf

Improvement in performance of a TeO2 acousto-optic imaging spectrometer

Acousto-optics(最近の展望)〔邦文〕

The problem of optical image deformations caused by the phenomenon of light beam diffraction in uniaxial crystals by ultrasonic waves is considered in the paper. A general analytical expression is derived describing a dependence of spatial deformations and transmission coefficients on incidence angles as well as on parameters of the crystal and the ultrasound. The most interesting wide-angle diffraction configurations are analyzed, and all types of spatial distortions and transfer functions are described.

Image aberrations caused by light diffraction via ultrasonic waves in uniaxial crystals

Acousto-optic processing of images is based on the angular selectivity of acousto-optic interaction resulting in spatial filtration of the image spectrum. We present recent theoretical and experimental investigations carried out in this field. Much attention is given to the analysis of the acousto-optic cell transfer function form depending on the crystal cut, the geometry of acousto-optic interaction, and the ultrasound frequency. Computer simulation results of the two-dimensional acousto-optic spatial filtration of some elementary images are presented. A new method of phase object visualization is suggested and examined that makes it possible to separate amplitude and phase information contained in an optical image. The potentialities of the acousto-optic image processing are experimentally demonstrated by examples of edge enhancement and optical wavefront visualization effects.

Acousto-optic image processing

Results are presented of a theoretical and experimental study of a new method of optical image processing based on two-dimensional acousto-optic filtration of the spatial spectrum of images. Most attention is concentrated on the analysis of the acousto-optic cell transfer function form and its dependence on crystal cut, geometry of acousto-optic interaction and ultrasound frequency. Results of computer simulation of acousto-optic spatial filtering are illustrated by the example of an object in the form of an amplitude grating. Experiments investigating the transfer functions of acousto-optic cells with collinear and tangential geometry of acousto-optic interaction are described. Acousto-optic image processing is demonstrated experimentally using the example of the edge enhancement effect for some elementary images.

Optical image processing by means of acousto-optic spatial filtration

The spatial structure of Bragg angles and the transfer functions of an acousto-optic cell are calculated for the cases of isotropic and anisotropic light diffraction in a uniaxial crystal. Their change with ultrasound frequency is traced. The possibility of image processing by acousto-optic filtration of the spatial spectrum of an image is considered. The results of experimental visualization of the transfer functions of a calcium molybdate crystal cell are presented.

Spatial structure of acousto-optic phase matching in uniaxial crystals

A method of visualization of phase objects is described based on selective properties of the Bragg diffraction of light by ultrasound. The main attention is focused on specific features of visualization in tangential geometry of the acousto-optical interaction. It is shown that, in the optimized case, the light intensity distribution in the visualized image is proportional to the phase gradient. The resolution and contrast of the visualized image are analyzed numerically. Potentialities of the method are illustrated by examples of computer simulation of the visualization effect.

Application of tangential geometry of the acousto-optical interaction to visualization of phase objects

Results are presented of a theoretical study of optical image processing based on two-dimensional acousto-optic filtration of the spatial spectrum of images. Most attention is concentrated on the analysis on the analysis of the acousto-optic transfer function form and its dependence on crystal cut, geometry of acousto-optic interaction and ultrasound frequency. Results of computer simulation of acousto-optic spatial filtering are illustrated by the example of an object in the form of an amplitude grating. For this object, effects of image differentiation and integration are demonstrated.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

D. E. Kostyuk

Papers

Acousto-optic image processing

Optical image processing by means of acousto-optic spatial filtration

Spatial structure of acousto-optic phase matching in uniaxial crystals

Application of tangential geometry of the acousto-optical interaction to visualization of phase objects

Application of acousto-optic selectivity for optical image processing