Kolobrodov V.G., Dobrovolska C.V., Mykytenko V.I., Tymchik G.S., Tiagur V.M., Komada P., Mussabekova A., Targeusizova A., Iskakova A. Spaceborne linear array imager's spatial resolution for arbitrary viewing angles (Conference Paper)

Simplified model of image forming in spaceborne linear array sensors at arbitrary sight angles is proposed in this paper. On basis of evaluation of system lens - linear array detector modulation transfer function (MTF), the equations were obtained that allow you to determine spatial resolution on Earth's surface. An example of pushbroom imager's MTF determination at sight of Nadir and with different slopes of lens optical axis is given. Image quality changes, which accompany lens optical axis angular inclination were studied. More research needed to determine the impact of lens aberrations on imager's MTF with arbitrary viewing angles.

Keywords: linear array detector, modulation transfer function, remote sensing, spatial resolution

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Kolobrodov V.G., Tymchik G.S., Kuchugura I.O. Design of the multiorder intraocular lenses

Abstract. Intraocular lenses (IOLs) are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL) which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.
Keywords: multiorder intraocular lens, diffraction efficiency, endless adaptation.

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Kolobrodov V.G., Tymchik G.S., NguyenQ.A. The problems of designing coherent spectrum analyzers.

The purpose of this article is to improve methods of calculating generalized characteristics of the coherent spectrum analyzers, which define the device’s properties and operation. These are the working range of spatial frequencies, the spatial spectral resolution and the energy resolution. Due to these methods, it is possible to choose optimal dimensions and parameters of components of the device to improve the properties of the last.

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In this article, we investigate the mathematical model of a digital optoelectronic processor for the purpose of determining the signal at the processor's output. The study of the model allows us to determine the distortions of the input signal of the processor, which are caused by the matrix spatio-temporal modulator. The developed physical and mathematical model of the processor made it possible to obtain an analytical expression for the signal at the processor's output. Its analysis shows that the formula for determining the spatial frequency differs significantly from the traditional formula. The spatial frequency depends on positions of the central and side maxima in the first-order diffraction maximum. In this case, the signal spectrum can be determined by measuring the lateral maximum, which is located closer to the optical axis of the processor. This allows to use of smaller matrix detectors, as well as to investigate the signal spectrum beyond the Nyquist frequency of the modulator.

https://doi.org/10.1117/12.2501595

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Kolobrodov V.G., Tymchyk G.S., Mykytenko V.I., Kolobrodov M.S. Physical and mathematical model of the digital coherent optical spectrum analyzer

A physical and mathematical model of digital coherent optical spectrum analyzers is discussed. In digital coherent optical spectrum analyzers the input signal is forming as a two-dimensional transparency by means of a spatial light modulator. After Fourier transformation with a lens, multiplication by a spatial filter and second Fourier transformation, the signal is captured by a matrix detector for further computer processing. A lot of digital coherent optical spectrum analyzers and their components (laser, lighting system, spatial light modulator, Fourier lens and matrix detector) models were developed to calculate the signal at the matrix detector output. They use the impulse response and transfer function to evaluate the effectiveness of digital coherent optical spectrum analyzers. The analysis of mathematical relationships shows that the use of a discrete spatial light modulator for the signal input and a matrix detector for light field registration in the spectral domain when combined with computer technology greatly extends the functionality of digital coherent optical spectrum analyzer. The formulas for impulse response and transfer function calculations were obtained, which allows to analyze and optimize the digital coherent optical spectrum analyzer basic characteristics.

Keywords: Matrix detector, Optical correlator, Optical spectrum analyzer, Spatial light modulator

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