Kolobrodov V.G.

Temperature Measurement Uncertainty of Patient by Medical Thermal Imager

The purpose of this article is to develop the method of estimation and research of measurement temperature uncertainty by the medical thermal imager in pathological zones depending on the distance between the patient and the thermal imager. The proposed method is based on the noise equivalent temperature difference (NETD) which depends on the linear objective magnification of the thermal imager.

Improvement of Calculating Medical Thermovision Camera Minimum Resolvable Temperature Difference

The paper is devoted to improvement of the equation for calculating the minimum resolvable temperature difference (MRTD) of medical thermovision camera by means of more sophisticated models of thermal images visual perception. An MRTD calculating algorithm, which is based on a more reliable approximation of the visual system modulation transfer function by Schultz, is considered. We obtain new expression for the bandwidth of Schultz’s approximation, which does not depend on the angular size of the Foucault pattern bar. An improved equation for calculating the MRTD was obtained.

Method for Assessing Modulation Transfer Function of Trifocal Intraocular Lens

The article investigates the quality of images formed by multifocal optical elements. The method for calculating of multifocal diffractive lens modulation transfer function (MTF) at presence of background is proposed. The method is based on a geometric calculation of the intensity of background images and the diffraction efficiency of the main image in each focal plane is considerated. The article has studied the contrast of main images formed by trifocal intraocular lens (IOL).

Infrared Hybrid Lenses with Corrected Spherical Aberration

This paper proposes the method of monochromatic lens spherical aberration correction by designing it as a hybrid lens. This method is based on the equation, which allows obtaining designing wavelength and focal distant of the hybrid lens diffractive part. The spherical aberration of the obtained diffractive part is equal to the refractive part of spherical aberration but has an opposite sign within a given clear aperture. Using this method, we calculate the plano-convex germanium hybrid lens with low f-number, which forms perfect spherical wavefront for the operating wavelength.

Reduction in Luminescence Enhancement Pulse Regime

This paper shows that significant energy losses in the Q-switched lasers are due to enhanced luminescence. We experimentally confirm the reduction of the relaxation time of the active centers with a high level of population inversion working levels. We propose a method of reducing losses of luminescence enhancement by using “complex” pump pulses. We analyze the use of “double” and “complex” pump pulses. Excitation of “double” pump pulse can reduce the loss by 7–10 %.

An Algorithm for Image Coding of Photographing Object Having a Large Range of Brightness

This paper proposes an algorithm for image coding of photographing object having a large range of brightness. It allows to achieve a high quality image of the photographing object by constructing it of the most informative images' elements of the object obtained under the same environmental conditions and different exposures. We also propose an algorithm for resulting HDR (High Dynamic Range) image coding from a series of LDR (Low Dynamic Range) images obtained by exposure bracketing or sensitivity bracketing of the optical receiver.

Investigation of Kinoform Element Chromatism

The paper investigates the chromatic characteristic of the kinoform element in a given spectral range. Based on the well-known chromatism theory we obtain more exact expressions of the chromatic focus shift and the dispersion coefficient. The enhanced chromatism theory determined that the chromatic focus shift and the dispersion coefficient depend not only on a spectral range but also on a Fresnel zone number. Based on the enahnced theory we analyze the kinoform chromatism in the spectral range of 8–12 µm.

Performance Evaluation for Multichannel Optoelectronic Surveillance Systems (MOESS) with Image Fusion

The article proposes the methodology for performance evaluation of MOESS with image fusion. This methodology combines probability of detection, recognition and identification with image fusion quality metric – targeting task performance. This metric takes into account the image formation process in single channel of MOESS, image fusion and human visual perception. Simulation results are well correlated with subjective tests. The proposed methodology allows matching the best image fusion method for current operating conditions.

The Problems of Designing Coherent Spectrum Analyzers

The purpose of this paper is to improve methods for designing coherent spectrum analyzers. Methods of calculating generalized characteristics such as the working range of spatial frequencies, the spatial spectral resolution and the energy resolution are suggested in this paper. To develop the methods of calculating we consider the most common scheme in which the transparency locates in the front focal plane of the Fourier lens. As transparency, we take a rectangular aperture that has spatial spectrum described by sync functions.

Matching the Resolution of the Lens and Matrix of Medical Thermal Camera

The paper considers the interrelation between radius of the confusion lens circle and the period matrix of modulation transfer function (MPF) with the concurrence lens and the detector. We propose two criteria of the alignment lens and the detector. The first criterion is the equality of the lens and matrix on the level while the second criterion is the equality of the MPF lens detector at the Nyquist frequency. Finally, we uncover the reduced dependence of the normalized radius of the circle of confusion on the value of the contrast of the lens alignment