Subject of study. This study investigated the spatial-spectral distortions arising from acousto-optic diffraction, which must be considered when constructing an optical system and calibrating acousto-optical device. Aim aimed to perform spatial spectral calibration imaging spectrometers based on tunable filters develop a technique for equalizing transmittance filter in entire working range. Method. To obtain undistorted data, both inhomogeneities need corrected. The procedure consisted...

Optical biomedical imaging in short wave infrared (SWIR) range within 0.9–1.7 μm is a rapidly developing technique. For this reason, there an increasing interest cost-effective and robust hardware for hyperspectral data acquisition range. Tunable-filter-based solutions are of particular as they provide image processing flexibility effectiveness terms collected volume. Acousto-optical tunable filters (AOTFs) unique set features necessary high-quality SWIR imaging. In paper, we discuss...

Subject of study. This study investigated a tunable source utilizing acousto-optic filtering, enabling control over the number, position, and intensity selected spectral lines, facilitating color reproduction within broad gamut. Aim aimed to assess accuracy this based on an acousto-optical filter, analyze influencing factors, develop algorithm for optimal component selection minimize errors. Methods. utilized layout recording characteristics determining coordinates applied developed identify...

Abstract A method for controlling precisely the intensities of several spectral components radiation generated by a multiwavelength laser system is described. The based on use simultaneous Bragg diffraction set acoustic waves corresponding frequencies and adjustment their amplitudes. efficiency proposed demonstrated example pulsed Nd:YAG (1064 nm) with intracavity parametric generation signal wave (1572 extracavity light conversion into higher harmonics sum frequencies. An independent...

Fatigue crack in rails and cyclic-loaded train parts is a contributory factor multiple railroad accidents. We address the problem of detection measurement at early stages, when total failure has not yet occurred. propose to combine acoustic emission (AE) testing for prediction growth with digital image correlation (DIC) its accurate quantitative characterization. In this study, we imitated fatigue appearance samples railway rail two by cyclic loading, applied these techniques inspection....

Identification of specific vascular patterns in skin formations is important for non-invasive differential diagnosis benign and malignant tissues. Accurate blood vessel mapping quantitative analysis the vessels morphology may increase diagnostic efficiency significantly comparison to conventional dermatoscopy methods. In this paper, we propose videocapillaroscopy technique visualization microvascular architecture right nevi area. It includes acquisition lesion images by exoscope-based...

We address non-contact detection of defects in the railway rails under their dynamic loading and propose to combine digital image correlation (DIC) finite element modeling (FEM). show that accurate model defect-free rail operating at same conditions as inspected one provides a reliable reference for experimental data. In this study, we tested samples with artificial fatigue cyclic loading, calculated displacement stress distributions different locations cracks via DIC validated obtained...

The article presents a technique for acousto-optical multispectral imaging based on choosing the most informative spectral channels and formation of multi-window transmission function an tunable filter. developed algorithm allows one to select combinations that provide high contrast given set objects backgrounds with known spectra. method is tested visualization 20 different object-background pairs similar color tone. results experiment demonstrate effectiveness proposed algorithm.

Subject of study. The study is focused on the investigation efficiency an absorber for s -polarized transverse ultrasonic waves in acousto-optical devices. Aim objectives are to determine structure acoustic field devices and develop a methodology assessing quality absorbers based analysis echo-pulse signals. Method. method leverages surface scattering degree ultrasound absorption reflection. Main results. A determining applied absorbent coatings has been developed. Practical significance....

Subject of study. This study focuses on methods for designing optical schemes acousto-optical (AO) hyperspectral devices tailored applied problems. Aim The objective is to develop a device incorporating tandem AO tunable filter the 0.85–1.6 µm spectral range. Method. system was designed using Zemax, supported by an original software module. simulation outcomes were experimentally verified. Main results. A short-wave infrared and manufactured. employs InGaAs sensor uses filtration enhance...

Optical system of spectral imaging device operating in visible and short-wave infrared range (SWIR) is designed. The developed based on the dual-spectrum acousto-optic tunable filter (AOTF) with two piezoelectric transducers, each working one ranges: (450 - 900 nm) or SWIR (900-1700 nm). Different types optical aberrations arising both ranges are analyzed. optimized to minimize these aberrations. characteristics discussed.

We address anisotropic acousto-optic (AO) filtration for spectral imaging applications. The design algorithm polarizer-free AOTF optical system is described. proper geometry of AO cell provides smaller and cheaper imager implementation. characteristics the are discussed.

The classic spoofing attack on vascular pattern biometric systems most often uses tools based a printed copy of the user's veins. This paper presents results an investigation into possibility using NIR absorbing/reflecting materials to produce against this type system. authors have developed concept new artefact that is produced directly attacker's hand without vein pattern. created in two stages: first stage, obscured with NIR-reflecting substances, and second control applied NIR-absorbing...

We report on the laser system generating pulsed coherent radiation of seven wavelengths in short-wave infrared and visible ranges: 1572 nm, 1064 786 635 532 524 nm 452 nm. It includes Nd:YAG (1064 nm), one LBO five KTP crystals for frequency up-conversion sum-frequency generation. Timing energy parameters all spectral components are presented. Proposed might be useful high-speed multispectral imaging, wavelength-multiplexed holography many other tasks.

Non-destructive testing of crystalline materials is an important task for optical instrumentation, industry, and computer engineering. Timely detection defects in their internal structure determines the efficiency safety various devices systems. Development methods non-contact analysis crystals urgent task. In this study, we propose to apply acousto-optical hyperspectral imaging crystal's structure. We developed experimental setup measured a spatial distribution transmittance spectra across...

Multiple-window acousto-optic filtering of wide-band (white) light allows to control chromaticity radiation in the visible range, which use a system consisting source and an filter for colour reproduction problems, instance, colorimetry, psychophysiology, spectral analysis, biomedicine other applied research areas requiring control. The article describes problem necessary when using two or three components (narrow bands), evaluates factors affecting accuracy demonstrates capability reach...

Abstract The safety of rail transport, including passenger traffic, largely depends on the timely diagnosis state infrastructure. To determine metal structures, method acoustic emission (AE) is used. It based registration elastic mechanical vibrations arising in material controlled object from a defect. AE highly informative, but interpretation measurement results often causes difficulties, especially when studying complex structural elements. In this paper, it proposed to use digital image...

Abstract One of the main factors contributing to accidents in railway transport are fatigue fractures rails, wheel axles and other critical parts rolling stock. Despite widespread use various physical control methods (eddy current, ultrasonic, magnetic), causes are, as a rule, missing defects structural elements car bogie. The paper considers application digital image correlation method measure spatial distribution deformations. results laboratory tests using this presented. possibility...