Light Spot Research Articles

Phase Alignment of an Array Optical Telescope System Using Balanced Detection

Differential phase shift keying (DPSK) modulation and multi-aperture receiving are effective means for suppressing flickering, deviation, and fragmentation of the light spot by atmospheric turbulence. What is challenging in coherent beam combination of such an array receiver system is to detect and compensate for phase deviation of sub-apertures. In this paper, a method of phase alignment of an array optical telescope system using balanced detection was proposed and demonstrated. The improved Mach Zehnder Interferometer (MZI) can demodulate the digital signal and recover the phase difference at the same time. It also brings a 3 dB gain to the receiver and improves the detection sensitivity of the system. Adequate simulations with OptiSystem and MATLAB were carried out to show that the power value remains near the ideal state of 2.75 mW, and the bit error rate is less than 10-9 after phase compensation, which indicates the effectiveness and accuracy of the proposed method. Furthermore, taking the communication interruption difference of ninety degrees as an example, the system bit error rate was reduced from 1 to 10-35, and communication was established again.

Early apple bruise recognition based on near-infrared imaging and grayscale gradient images

Early apple bruises, especially those occurring within half an hour, usually have no external symptoms and are difficult to recognize. This study developed a fast and nondestructive detection method for early bruises based on near-infrared camera imaging and image recognition. A total of 31 apple samples were photographed on both sides of each apple. Grayscale images of the sound apples were captured using a near-infrared camera with a wavelength region between 900 and 2350 nm. Images (n = 62) of apples without bruises were collected. The identical apples were artificially damaged and photographed at two stages (0 h, 0.5 h) by the near-infrared camera, and a total of 186 grayscale images were collected. As the light spot on the surface of apples limits the accuracy in detecting defects, a compound image pre-processing method was proposed consisting of nonlinear grayscale transformation and frequency-domain image filtering techniques. Finally, the gradient image is obtained by taking the first-order derivative of the preprocessed image. Since bruise had distinct edges, the gradient grayscale images of apples are more favorable for bruise identification. The compound method obtained a 97.62% classification accuracy for nonbruised apples and apples with fresh bruises. The experimental results show that it is feasible to identify early bruises in apples based on near-infrared camera imaging and gradient grayscale images. In the subsequent study, the method will be further improved, especially the parameters involved in the algorithm could be adjusted to adaptive variables. In addition, the system will be explored to be suitable for online apple bruise detection.

Simulation of an acousto-optic deflector of terahertz radiation based on a sectioned ultrasound transducer

Subject of study. The acousto-optic diffraction features of terahertz radiation by an ultrasonic field with periodic inhomogeneity are theoretically evaluated in this study. Aim of study. This study aims to identify the optimal parameters for implementing an effective terahertz radiation deflector. Method. Liquefied sulfur hexafluoride gas is selected as the interaction medium to enhance the energy efficiency of the deflector. Additionally, the application of a sectioned phased ultrasound transducer is proposed to increase the number of resolvable light spots. Main results. The features of the acoustic field generated by the transducer are demonstrated. Analytical relations are derived for the main parameters of the acousto-optic deflector. Practical significance. A possible fivefold increase in the number of resolvable spots compared with an acousto-optic deflector based on a single-section transducer of the same length is demonstrated.

Increase in Yield and Immunity in Bam OTM Treated Papaya Plants in India

Background: Carica papaya L. (family Caricaceae) is one of the popular fruits in world. As with many tropical and subtropical crops, papaya is host to various pests and pathogens. More than 700 papaya plants were infected by unknown virus. The incidence of plants infected with leaf curl disease was 50-75%, but the infection was very severe. A typical curling and thickening were observed. The infection spread by air and rainwater to nearby papaya farms. Methods: This study reports the effect of BamO formulation on the biotic stress of the Papaya plant. BamO was sprayed on the plants and its effect was observed. After six days of Bam O treatment, new healthy leaves were observed on the plants. Result: The yellow and old leaves were dropped from the plants. After 2 months of the treatment BamO, the fruits were elongated and having similar shapes without uneven bumps. The green fruits without any dark or light spots were observed in BamO treated plants. Priming effect was observed by GCMS analysis, the 3 methylsalicylic acid increased quantity was observed in 7th day and 30th day samples of BamO treated plants. The BamO treatment not only increased the immunity of the plant but found effective in increasing yield of the papaya plants. In BamO treated papaya plants, the total yield obtained was 92.10 tonnes per 444 plants.

Synthesis of a spin-orbit beam lattice using a Dammann grating

In this paper, we propose a method for the generation of a two-dimensional spin-orbit beam lattice using a Dammann grating. A Dammann grating is fabricated and is illuminated by ellipse field/vector filed singular beam that contains a polarization singularity. Since, Dammann grating is used to produce equal-intensity light spots, each of the spin-orbit beams in the lattice has equal intensity distribution. Interestingly, they also have the same polarization distribution as that of the input light. Unlike the interferometric methods of lattice generation, the diffractive method proposed here produces lattices of the same index singularities. Simulation and experimental results are provided to demonstrate the concept.

3D error calibration of spatial spots based on dual position-sensitive detectors.

In this paper, a dual position-sensitive detector-based vision measurement system camera is built instead of a traditional CCD camera. The 3D position information for the light point is calculated according to the 2D coordinate information of a certain light point in the space illuminated on the two position-sensitive detector (PSD) photosensitive surfaces, which is used for position detection of the spatial light point. In addition, the positioning model for 2D PSDs with different spot sizes in the Gaussian spot mode is derived by the mathematical model of Lucovsky's differential equation for a PSD. For the nonlinear distortion of the PSD, a nonlinear error calibration method using a particle swarm combined with a back propagation neural network is proposed to correct the errors in the measured values through the relationship between the input and output values, to obtain the predicted value that approximates the real coordinates. Then, by comparing the influence of different spot sizes on the positioning accuracy, we conclude that the smaller the spot formed by the convergence of the beam under the optical lens, the higher the positioning accuracy. We believe this conclusion can help improve the accuracy of PSD measurements. Finally, a red LED light spot is set up, and the 3D position measurement and error calibration of the light spot is done by dual PSD cameras, which better solves the position detection problem of a space light spot under close-range conditions because it is fast, reliable, and easy to implement. It also provides an effective method to detect the motion trajectory of a moving light spot in space.

First Report of Puccinia modiolae Causing Rust Disease on Malva verticillata in Korea.

Malva verticillata (Malvaceae), commonly called Chinese mallow or whorled mallow, is an annual herb native to East Asia and is currently distributed worldwide. In Korea, this plant is cultivated as a leafy vegetable and cooked like spinach or used in soups and also as a medicine material. In March 2022, typical symptoms of rust disease were observed on M. verticillata in a plastic house (37°22'12″ N, 127°34'30" E) in Yeoju, Korea. Yellow or light green round chlorotic spots appeared on the upper surface of infected leaves, while reddish-brown or dark brown rust pustules formed on its lower surface. Infection occurred in 10% of M. verticillata plants surveyed, and disease severity ranged between 30-90%. A representative sample was deposited in the Kunsan National University Herbarium (KSNUH1762). Telia were mostly hypophyllous, reddish-brown to dark brown, round, mostly grouped, and 0.3-0.7 mm in diameter. Teliospores were mostly two-celled, but rarely one or three-celled, yellowish to light brown, fusoid, and 42.9-101 × 10.8- to 18.8 μm (average 72.7 ± 12.3 × 14.2 ± 1.92 μm [mean ± SD]; n = 50), with a smooth, hyaline to yellowish wall of 1.0-2.5 μm thickness. The morphological characteristics were similar to those reported for Puccinia modiolae (Aime and Abbasi 2018; Albu et al. 2019). To confirm the morphological identification, genomic DNA was extracted from the teliospores of an infected leaf. The internal transcribed spacer (ITS) with primers ITS5-u and ITS4rust (Pfunder and Schürch 2001) and the large subunit (LSU) rDNA with primers LRust1R and LRust3 (Beenken et al. 2012) were amplified for sequencing. The resulting sequences were deposited in GenBank with accession numbers ON631218 for ITS and ON631226 for LSU. BLASTn search showed that the Korean sample was identical to the ITS sequences of P. modiolae from Modiola caroliniana (MK458693-MK458697) and the LSU sequences from M. caroliniana, Malva sylvestris, and Alcea rosea (MH742976, MH742977, and MH742978). In the phylogenetic trees of the ITS and LSU sequences, the Korean sample was grouped with the reference sequences of P. modiolae, with the maximum supporting value. For the pathogenicity test, rust-infected leaf discs were placed on the upper or lower surfaces of leaves of three healthy M. verticillata. Three non-inoculated plants served as controls. Inoculated and non-inoculated plants were maintained in a growth chamber at 22°C, a 16/8 h light cycle, and 80% humidity. After three weeks, all inoculated plants developed evident rust symptoms on the upper and lower surfaces of the leaves on which the leaf discs were placed, whereas the control plants remained symptomless. The pathogen present on the inoculated plants was confirmed to be the same pathogen as that observed in the field, fulfilling Koch's postulates. Based on the morphological investigation, sequence analysis, and pathogenicity tests, P. modiolae was identified as the causal agent of rust disease on M. verticillata. To date, this pathogen has been reported on seven Malvaceae plants, including Alcea rosea, Althaea officinalis, Lavatera arborea, Malva parviflora, Malva sylvestris, Modiola caroliniana, and Modiola sp., in North and South America (Farr and Rossman 2022). However, it has not been reported in Asia or Korea. This study is the first report of rust disease on M. verticillata worldwide. Considering its high incidence rate and severe damage, this pathogen is a potential concern for the cultivation of M. verticillata in Korea. This finding could contribute to developing phytosanitary and control treatments for this disease.

Evaluation of the scintillation screens used for low energy pulsed ion beam profiling

For a compact pulsed sealed-tube neutron generator using vacuum arc as ion source, an ion beams diagnostic system based on scintillation screen was established. And the transverse intensity distribution of the deuterium ions on the target of the pulsed neutron generator was obtained. In order to validate the accuracy of the diagnostic system, the ion irradiation effect of the Al2O3, Quartz and YAP scintillation screens were studied. Steady pulsed deuterium ion beam with energy and intensity comparable to the pulsed ion beam used in the neutron generator was let continuously irradiated on the scintillation screens, and the light yield and spot size changes of the screens were recorded. Results showed that, YAP screens own the worst radiation hardness among the three. For Al2O3 and Quartz screens, though their light yield degraded with the ion radiation, the measured beam profile almost not changed for integrated beam intensity of up to 2.5 × 1014 ions/mm2. Therefore, the diagnostic system can provide accurate results for the ion beam diagnostic for neutron generators.

An FPGA-Based Laser Virtual Scale Method for Structural Crack Measurement

Real-time systems for measuring structural cracks are of great significance due to their computational and cost efficacy, inherent hazards, and detection discrepancies associated with the manual visual assessment of structures. The precision and effectiveness of image measurement approaches increased their applications in vast regions. This article proposes a field-programmable gate array (FPGA)-based laser virtual scale algorithm for noncontact real-time measurement of structural crack images. The device first sends two parallel beams and then applies image processing techniques, including de-noising with median and morphological filtering, as well as Sobel-operator-based edge extraction, to process and localize the light spots. Afterwards, it acquires the scale of the pixel distance to the physical distance and then derives the actual size of the crack. By processing and positioning, the FPGA acquires the scale of the pixel distance to the physical space and then derives the actual size of the crack. The experimental study on crack measurements demonstrates that the proposed technique has precise and reliable results. The error rate is approximately 2.47%, sufficient to meet measurement accuracy criteria. Moreover, experimental results suggest that the processing time for one frame using an FPGA is about 54 ms, and that the hardware acceleration provided using an FPGA is approximately 120 times that of a PC, allowing for real-time operation. The proposed method is a simple and computationally efficient tool with better efficacy for noncontact measurements.

Graphene/Ge Photoconductive Position-Sensitive Detectors Based on the Charge Injection Effect

Position-sensitive detectors (PSDs) are of great significance to optical communication, automatic alignment, and dislocation detection domains, by precisely obtaining the position information of infrared light spots which are invisible to human eyes. Herein, a kind of PSD based on graphene/germanium (Ge) heterojunction architecture is proposed and demonstrated, which exhibits amplified signals by unitizing the charge injection effect. Driven by the graphene/Ge heterojunction, a large number of photogenerated carriers diffuse from the incident position of the light spot and subsequently inject into graphene, which ultimately generates a photoresponse with high efficiency. The experimental results show that the device can exhibit a fast response speed of 3 μs, a high responsivity of ~40 A/W, and a detection distance of 3000 μm at the 1550 nm band, which hints that the graphene/Ge heterojunction can be used as an efficient platform for near-infrared light spot position sensing.

Design and characterization of multijunction photovoltaic laser power converters for nonuniform irradiance light profiles

AbstractNonuniform irradiance profiles of lasers used in power‐by‐light systems deteriorate the efficiency of photovoltaic laser power converters. We analyze three approaches to deal with this efficiency loss: (1) to design the power converter front grid for the nonuniform light received from the power‐by‐light system; (2) to strengthen the peak current and decrease the series resistance of tunnel junctions; and (3) to homogenize the light spot impinging the power converter by simply distancing it from the laser fiber. In the context of these approaches, this paper tackles the optimization of multijunction photovoltaic laser power converters to achieve their maximum efficiency under nonuniform irradiance profiles, without using any optical element to homogenize them and, this way, reproducing realistic operating conditions. As a direct application of the design shown in this paper, we have increased the experimental efficiency of our GaAs devices by up to 3% absolute for a nominal laser wavelength of 857 nm.

Damage caused by Tuckerella ornata (Acari: Tuckerellidae) on cocoa fruits (Theobroma cacao) in the Amazon region, state of Pará, Brazil

The study aimed to report peacock mites (Acari: Tuckerellidae) on cocoa fruits (Theobroma cacao L.; Malvaceae) in the northeast Bragantina region, state of Pará, Brazil. Two mite species were identified, Tuckerella ornata, with 149 specimens, 32.89% on leaves and 67.11% on fruits, and Tuckerella knorri, with only two specimens on leaves. It was found that green fruits with T. ornata significantly reduced the size and weight of seeds. More attacked fruits, with more severe damage, showed deformations and thick cracks. Significant damage was noted in the Forastero cocoa seeds, visible to the naked eye, with light brown spots and a fine crack on the epidermis.

First Report of Yeast-Spot Disease of Soybean Seeds Caused by Eremothecium coryli in Serbia.

Over the last 15 years, the area planted with soybeans (Glycine max) in Serbia has increased drastically, from 131,000 hectares in 2005 to 230,000 in 2019, and the average yield reached 3.2 t/ha in 2020. The Province of Vojvodina is the most important soybean production region with 95% of the total soybean area in Serbia (www.stat.gov.rs). During the 2021 growing season, soybean seeds with various kinds of symptoms including colour changes, light and dark brown spots, blotching, necrosis, and shriveling were collected from soybean field before harvest of soybean cv. Dukat in the Tamiš locality (South Banat District, Vojvodina Province: GPS: 44°56'12.936"N 20°43'24.216"E) in Serbia. The incidence of symptomatic seeds was estimated at 6.4%. Symptomatic soybean seeds were surface disinfected with 2% NaOCl for 2 min, rinsed in sterile water, dried on sterile filter paper, placed on potato dextrose agar (PDA) and were incubated at 25°C in the dark for 10 to 14 days. The identification of fungi at the genus level based on morphological characteristics revealed the presence of species of Macrophomina, Botrytis, Cercospora and Alternaria, which were previously reported as pathogens of soybean seed in Serbia (Krsmanović et al. 2020). Also, seven white to slightly creamy colonies with yeast-like morphology were observed around seeds expressing discoloration and necrotic and sunken spots. Ten days later, microscopic observations of yeast-like colonies revealed the presence of globose budding cells (diameter of 20 to 28 μm) mostly single or rarely in short chains. Also, two to eight needle-shaped ascospores (52 to 80 μm in length) were arranged lengthwise in many cylindrical to naviculate asci (60 to 96 x 8 to 12, avg. 72.4 x 9.2 µm). Ascospores were with a unilateral, slender, flexuous, whip-like appendage. The morphology of the different fungal structures indicated that the pathogen was Eremothecium coryli (Pelgion) Kurtzman and it was further supported by molecular identification. Total DNA was extracted directly from fungal mycelium with a DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) and PCR amplification performed with primers ITS1F (Gardes and Bruns 1993) and ITS4 (White et al. 1990). Sequence analysis of ITS region revealed that the Serbian isolate ND2/21 (GenBank Accession No. OL958602) shared the highest nucleotide identity of 100% with E. coryli isolate (Accession No. KY103387). For pathogenicity test, fresh soybean seeds (cv. Sava) were surface-disinfected with 2% NaOCl and rinsed in sterile water before inoculation. The seeds were pierced 3-4 times with a sterile insect pin through a drop of yeast suspension (concentration 106 ascospores/ml) of one selected single-spore isolate (ND2-21). Similarly, control seeds were pierced with sterile insect pins through a drop of sterile distilled water. Five inoculated seeds and control (five replicates per treatment) were arranged uniformly in a Petri dish (9 cm diameter) and incubated at 22 to 25°C in the dark and kept under >95% relative humidity during the first 48 h. Twenty days after inoculation, small brown necrotic lesions were visible on the soybean seeds. Re-isolation from symptomatic seeds on PDA dishes yielded yeast-like colonies with the same morphological characteristics as those used for inoculation, thus confirming Koch's postulates. The control seeds had no symptoms. This fungus is widely known as a pathogen of yeast spot disease on soybean seeds (Heinrichs et al. 1976; Kimura et al. 2008), but to our knowledge, it has never been reported in Serbia. Considering that invasive species Nezara viridula L. and Halyomorpha halys (STÅL, 1855), the vectors of this fungus, were reported in our country (Kereši et al. 2012; Šeat 2015) and that their mass appearance has been documented in recent years (Konjević et al. 2020), the presence of this pathogen has the potential to cause considerable damage and severe yield losses, resulting in significant economic impact on soybean production in Serbia.

Deep Neural Network-Based 4-Quadrant Analog Sun Sensor Calibration

Many error sources influence the calibration experiment of 4-quadrant sun sensors, making the calibration of sun sensors cumbersome and its accuracy difficult to improve. Any continuous function on a bounded closed set can be approximated by a deep neural network. This paper uses the deep neural network model to approximate the error model. The data-driven training network is adopted to continuously modify the model parameters to fit the error compensation model and ensure that the accuracy reaches the target requirements after calibration. Considering that the deep neural network model needs a considerable amount of data, the neural network model training is divided in 2 stages. In the preliminary stage, cubic surface fitting is used to generate a dataset, which is small in size and controllable. After the completion of the initial training, the experimental data are used to fine-tune the model to achieve error compensation. The accuracy can be improved from 1° (1 σ ) to 0.1° (1 σ ) after the incident angle of the sun sensor is corrected. The error compensation model eliminates the loss of accuracy caused by the distortion of light spots at the edge of the field angle and provides a favorable condition for the expansion of the field angle of the 4-quadrant analog sun sensor.

Light spot detection of diamond wire based on deep learning

Light spot detection of diamond wire based on deep learning

Design of DOE Based on Modified GS Algorithm for Preparation of Micron‑Scale Uniform Light Spot in Ultraviolet Band

Design of DOE Based on Modified GS Algorithm for Preparation of Micron‑Scale Uniform Light Spot in Ultraviolet Band

Waving Effect Characterization for Water-to-Air Optical Wireless Communication

In this paper, we establish and experimentally verify a water-to-air (W2A) visible light communication (VLC) system through dynamic air-water interface. Considering the complexity of waves in real environments, we divide waves into largescale wave and small-scale wave. Monte Carlo simulation and experimental results show that small-scale wave mainly affects the energy distribution of the light spot on the receiving plane and the variation frequency of link gain, while largescale wave mainly affects the coverage of the light spot. In the W2A-VLC system based on light-emitting diode (LED), the statistical characteristics of variation time and link gain are mainly related to the small-scale wave, and the effect of large-scale wave can be treated as slow fading. In order to design a reliable communication system, a large-divergence-angle LED array and avalanche photodiode (APD) array are used under dynamic water surface. We investigate three cases, namely single-input multiple-output (SIMO), multiple-input single-output (MISO) and multiple-input multiple-output (MIMO). In the SIMO or MISO systems, the correlation coefficient of channel gain decreases with the inter-receiver or inter-transmitter distance. A significant transmission performance enhancement can be achieved by deploying more transmitters or receivers and increasing the distance between the transmitters or receivers. A MIMO structure can effectively increase the achievable rate. We further establish a W2A-VLC link in a deep wave pool to verify our research in the real environment. The results show that more intensive small-scale wave yields higher bit error rate (BER), and the diversity scheme can improve the transmission stability and decrease BER.

Значения прилагательного алаг / ала в бурятском и хакасском языках (на примере эпических произведений)

This paper presents a comparative analysis of epic works aimed at examining the semantic structures of two adjectives, alag in Buryat and ala in Khakas. The analysis findings provide a comprehensive picture of the semantic space of the words under study. Special attention is paid to word-to-word connections in the epic language, allowing the nomination motive to be identified. This study has contributed to uncovering the new meanings of the adjective alag, namely “brilliant,” “anxious,” and “dulled,” which are not specified in Mongolian-Russian dictionaries. The issue of the primary and secondary meanings is considered to be crucial in studying the semantic transitions within a polysemant. It is suggested that the meaning of “motley” was derived from the meaning “brilliant,” referring to the predominance of light spots or stripes. The word alag is assumed to have combined with the synonyms erēn “variegated” and sōhor “motley” in the epos language after losing the supposed primary meaning “brilliant.” Identifying the common meaning of “shining” in Turkic-Mongolian epic reflects the peculiarities of the national-cultural worldview of related peoples. The language representation of perceptual information is regarded as a result of the primary stage of self-knowledge, reflecting the mental-psychological and national-cultural specificity of Turkic-Mongolian people. Studying the semantic structure of the adjective alag / ala is expected to identify some general lines of the perceptual information implementation in Turkic and Mongolian languages.

Talbot effect of ring laser array realized by Gyrator canonical transformation

We propose a ring laser array structure and study the Talbot effect. By comparing with the one-dimensional laser array, the near-field distribution of the identical intensity of the ring laser array without edge effect is obtained, which can be more conducive to improving the capability of the external cavity phase locking of lasers. In this paper, Talbot effect and self imaging condition of ring laser array in polar coordinates are calculated by using Gyrator canonical transformation. The sub-image distribution at the fractional Talbot distance is further analyzed. The optical profile and phase distribution of the ring laser array at the fractional Talbot distance are simulated, which are mutually verified with the theoretical calculation results. At a quarter of the Talbot distance, the number of sub-images is twice that of the emitters. The light intensities of the sub-images are identical, and thedifference in phase between adjacent sub-images is <inline-formula><tex-math id="M1">\begin{document}${\pi }/{2}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20222412_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20222412_M1.png"/></alternatives></inline-formula>. At half of the Talbot distance, the number of sub-images is the same as that of the emitters, while the spatial position of sub-image is shifted by half a cycle along the angular direction. Moreover, the sub-images with twice the number of the emitters are present in three quarters of the Talbot distance. The light intensities of the sub-images are identical and the difference in phase between adjacent sub-images is <inline-formula><tex-math id="M2">\begin{document}$- {\pi }/{2}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20222412_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20222412_M2.png"/></alternatives></inline-formula>. Further, the Talbot images with the same spatial and phase distribution as the emitters are generated along the angular direction at the Talbot distance. The optical profile and phase distribution of one dimensional laser array at the fractional Talbot distance are also simulated by FDTD Solutions for comparison. It is found that the edge effect of one-dimensional laser array leads to the uneven distribution of near-field light intensity, in which the intensity of light spot on the edge of array is significantly lower than that in the center of array. While the Talbot sub-images of ring laser array with identical light intensity are obtained. Therefore, We consider that the ring laser array can effectively eliminate the edge effect. The results are helpful in studying the external cavity phase locking of ring laser arrays and its applications in the field of high brightness coherent laser and quantum measurement.

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The work is devoted to the study of the characteristics of the optical-mechanical sensor for the measurement control of geometric characteristics of firearms bores. The results of the analysis of publications devoted to the structure and application of measuring devices based on the triangulation method of distances determining are given. The limited possibility of applying of the results obtained in known works in the creation of an optical-mechanical sensor for diagnosing of firearms bores was noted. Features of construction and basic geometric parameters of the optical-mechanical sensor are considered. A description of the measurement method is given, which provides for the calculation of the desired distance using the known parameters of the optical scheme of the optical-mechanical sensor and the linear and angular parameters of the triangles consisting of the elements of the optical scheme of the sensor. An expression for the dependence of the angle between the optical axis of the receiving lens and the light-sensitive detector from other basic geometric parameters of the optical-mechanical sensor was obtained using the basic formula for a thin lens. The expression determines the angular position of the light-sensitive detector in relation to the main optical axis of the receiving lens and should be taken into account as a limitation in the practical implementation of the sensor. The conversion function of the optical-mechanical sensor is determined, which establishes the dependence between the increment of the coordinate of the light spot on the surface of the light-sensitive detector of the sensor and the increment of the radius of the bore. An expression for solving the inverse problem � calculating the value of the input value based on measurement information about the output value � was obtained. Graphs of these functions for typical combinations of optical-mechanical sensor parameters are given. A study of the linearity of the conversion function of the optical-mechanical sensor and the nature of its sensitivity change within the range of measurement was conducted.