A Fourier correlator with a spatial filter in the form of an axicon is considered. A convolution-type integral expression that relates complex amplitudes at the input and output of the optical system is obtained.
Results on investigating the possibilities of color and monochromatic aberrations of the needle-shaped unit of a rigid endoscope, which includes gradient-index optical elements: an objective and a translator, are presented. It is shown that a hybrid compensator consisting of a Wood lens and a homogeneous meniscus can serve as an effective corrector of its aberrations.
The Fourier-Fresnel transform based on geometrical optics, which is performed by converging and diverging lenses, and used in speckle interferometry to determine with a variable sensitivity the shift in the plane and the inclination of elements of the surface of deformed objects is considered.
Results of theoretical investigation of the zone shadowing effect in focusing diffractive optical elements are presented. It is shown that fabrication of a diffractive optical element on a curvilinear surface will substantially reduce this effect and increase the coefficient of usage of element surface.
Large-dimension signals and images are frequently reconstructed by means of iterative algorithms in which the regularization parameter is the number of iteration at which the construction of the minimizing sequence stops. The choice of the stopping iteration is an important problem. Its solution requires substantial a priori information unavailable in practice. The present paper, using the cross-validation method, proposes an algorithm for estimating the number of iteration at which the solution has the minimum error.
The maximum likelihood method of simultaneous detection of an inhomogeneous image and estimation of its area in the presence of a space noise is considered. Exact characteristics of the algorithm performance are found. The obtained results are applied to an image in the shape of ellipse with a linearly varied intensity.
An algorithm for segmentation of anisotropic images and construction of a field of directions, which is based on analyzing integral characteristics of a local energy spectrum calculated in a sliding window, is proposed. The efficiency of applying the algorithm to processing images of a microrelief of traces of real objects identified while studying clues is illustrated.
A hydroacoustic signal processing method is considered. The method uses an adaptive environment model including the medium of propagation and the radiation sources contained in it, and also a receiving antenna array model. Results of investigation on a software test complex are presented. It is shown that the method can be successfully applied to problems of primary hydroacoustic signal processing.
Peculiarities of application of broadband emission detectors in spectral ratio pyrometers are considered. To calculate the temperature, it is proposed to use the Planck formula that ensures a high measurement accuracy over a wide range of temperatures.
A new type of integrated-optic polarization splitter is proposed. Its operation is based on significant mode birefringence of a four-layer Y-brancher with specially defined parameters. The artificial birefringence is formed by combining a weakly guided waveguide and an abruptly inhomogeneous waveguide. The main parameters of the device are estimated by the finite-difference beam propagation method.
