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Your search keyword '"Cheremkhin, Pavel A."' showing total 131 results
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131 results on '"Cheremkhin, Pavel A."'

5. Interpolation-Filtering Method for Image Improvement in Digital Holography.

Author

Kozlov, Alexander V., Cheremkhin, Pavel A., Svistunov, Andrey S., Rodin, Vladislav G., Starikov, Rostislav S., and Evtikhiev, Nikolay N.

Subjects
SPECKLE interference, DIGITAL image processing, IMAGE reconstruction, HOLOGRAPHY, INTERPOLATION
Abstract

Digital holography is actively used for the characterization of objects and 3D-scenes, tracking changes in medium parameters, 3D shape reconstruction, detection of micro-object positions, etc. To obtain high-quality images of objects, it is often necessary to register a set of holograms or to select a noise suppression method for specific experimental conditions. In this paper, we propose a method to improve filtering in digital holography. The method requires a single hologram only. It utilizes interpolation upscaling of the reconstructed image size, filtering (e.g., median, BM3D, or NLM), and interpolation to the original image size. The method is validated on computer-generated and experimentally registered digital holograms. Interpolation methods coefficients and filter parameters were analyzed. The quality is improved in comparison with digital image filtering up to 1.4 times in speckle contrast on the registered holograms and up to 17% and 29% in SSIM and NSTD values on the computer-generated holograms. The proposed method is convenient in practice since its realization requires small changes of standard filters, improving the quality of the reconstructed image. [ABSTRACT FROM AUTHOR]

Published
2024
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13. A Family of Methods Based on Automatic Segmentation for Estimating Digital Camera Noise: A Review

Author

Kozlov, Alexander V., Rodin, Vladislav G., Starikov, Rostislav S., Evtikhiev, Nikolay N., and Cheremkhin, Pavel A.

Abstract

Digital camera noise information is useful in various applications: image enhancement and postprocessing, device selection for a particular system, recognition, decision making, and forensics, and so on. Therefore, there is a need for fast and reliable noise estimation methods. There are set of methods based on automatic segmentation of uniform target (ASUT), automatic segmentation of nonuniform target (ASNT, original and modified), automatic segmentation of strip target (ASST) ones, and using an automatic segmentation of a single image (ASSI). This article discusses these methods grouped into one family. The methods in this family estimate noise parameters by processing only a few images. The results are compared with the EMVA 1288 Standard. The simplest and least time-consuming methods are ASSI and ASNT. However, they do not allow the estimation of all noise characteristics. ASST and ASUT provide all noise data, but ASST is more complex due to the target design. ASUT can be considered the most balanced and accurate.

Published
2024
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29. Lensless Optical Encryption of Multilevel Digital Data Containers Using Spatially Incoherent Illumination.

Author

Cheremkhin, Pavel, Evtikhiev, Nikolay, Krasnov, Vitaly, Ryabcev, Ilya, Shifrina, Anna, and Starikov, Rostislav

Subjects
TWO-dimensional bar codes, DATA structures, ERROR correction (Information theory), SPATIAL light modulators, CONTAINERS, LIGHTING, DATA encryption, DIGITAL watermarking
Abstract

The necessity of the correction of errors emerging during the optical encryption process led to the extensive use of data containers such as QR codes. However, due to specifics of optical encryption, QR codes are not very well suited for the task, which results in low error correction capabilities in optical experiments mainly due to easily breakable QR code's service elements and byte data structure. In this paper, we present optical implementation of information optical encryption system utilizing new multilevel customizable digital data containers with high data density. The results of optical experiments demonstrate efficient error correction capabilities of the new data container. [ABSTRACT FROM AUTHOR]

Published
2022
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