Home – Home – Jornals – Avtometriya 2007 number 3

The accuracy of estimating the shift between two discrete images of the same scene is analyzed in the situation when the shift value is under the sampling step. A new algorithm is proposed for estimating the shift. The algorithm requires a low computational complexity and its estimate errors are small. Results of computational experiments verify its advantages over the known algorithms.

A control scheme for mobile robot formation in the leader following mode is proposed. It enables to track the target and is based on using a sliding mode along the desired trajectory in the state space. Results of modeling using MATLAB/SIMULINK environment are presented. They confirm efficiency of the proposed algorithm.

Freeforms synthesized by means of perturbation functions are considered. A special feature of the freeforms based on the scalar perturbation functions and the method of their visualization is that the time of geometrical processing and the amount of data required for modeling the surface do not depend on its geometry. The freeforms based on the analytical perturbation functions have an advantage of spline representation of surfaces, that is, a high degree of smoothness, and an advantage of arbitrary form for a small number of perturbation functions.

Concepts of using new perspective systems in computer graphics are considered. The systems open up opportunities for rendering 3D visual scenes similar to the natural visual perception.

The filtering of projections in tomography algorithms, which is based on the regularization of distribution 1/z², is investigated. Numerical simulations validate that changing the filter support will substantially improve the tomograms. Comparison of the results of reconstruction by the 1/z²-filtering algorithm and the Shepp

Types of interpolation in calculating the frame-to-frame difference for decreasing the influence of the stationary background when detecting point objects are compared. The comparison is done for an observation system with a photodetector array and an oscillating axis. Methods of interpolation in the presence of a fractional shift (below the photodetector array step) are considered. Computational experiments estimating the efficiency of the methods upon detecting point objects were carried out.

The possibility of decreasing the depth of interference region in the Fizeau interferometer configuration with a semiconductor laser is considered for problems concerned with inspection of plane-parallel plates.

An experimental assembly is created and a method for simultaneous studying dynamics of phototransformation of holographic photopolymer materials by spectrophotometric and interferometric methods is elaborated. A special diffraction interferometer with combined branches is developed. The interferometer ensures the sensitivity to the change in the refractive index Dn ~ 10^-3 for ~100 mm specimens.

Peculiarities of designing and determining the refraction (lens power) and the diffraction efficiency of bifocal hybrid (diffractive-refractive) intraocular lenses (IOL)

Passive mode-locking with equidistant ultrashort pulses in the laser cavity due to additional weak modulation of the losses or the refractive index is analyzed. The velocity of the relative pulse motion and the time of establishing the harmonic passive mode-locking mode are analytically estimated.

A multibeam interferometer with oscillating mirrors is theoretically investigated. The exact solution to the main equation for the interferometer and expressions for its transfer functions, i.e., generalized reflection and transmission factors, are obtained in a plane-wave approximation.

A method for measuring diameters of circular reflecting cylinders is discussed. The method consists in processing a diffraction pattern that is formed in the near-field zone by illuminating the object edges by a plane monochromatic beam. An equivalent mathematical model of forming a diffraction field is developed and experimentally validated. The model makes it possible to obtain analytical functions describing the distribution of the field from the circular reflecting cylinder. The influence of the cylinder reflecting surface on the diffraction pattern parameters is studied. A highly accurate algorithm is proposed for calculating the diameter of the cylindrical article by its Fresnel diffraction pattern with an error under 1 m.

A method is proposed for parallel (simultaneous) readout of information from three- dimensional