Dr. Mohamed S. El-Tokhy Profile

Dr. Mohamed S. El-Tokhy

at Egyptian Atomic Energy Authority

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Publications (6)

SPIE Journal Paper | 21 April 2020

Improvements of resolution and conversion efficiency of optoelectronic imaging instruments based on graphene and quantum dot bases of photodetectors with light-emitting diodes

Mohamed El-Tokhy

OE, Vol. 59, Issue 04, 043102, (April 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.4.043102

KEYWORDS: Photons, Light emitting diodes, Near infrared, Image resolution, Graphene, Electrons, Optoelectronics, Optical engineering, Photodetectors, Absorption

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SPIE Journal Paper | 4 March 2020

Ultimate neutron and x-ray radiography images compression using artificial bee colony and firefly optimization algorithms

Mohamed El-Tokhy

JEI, Vol. 29, Issue 02, 023003, (March 2020) https://doi.org/10.1117/12.10.1117/1.JEI.29.2.023003

KEYWORDS: Image compression, Radiography, X-rays, X-ray imaging, Reconstruction algorithms, Optimization (mathematics), Computer programming, Binary data, Image quality, Detection and tracking algorithms

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Optimum compression ratio (OCR) of neutron and x-ray radiography images with minimum decomposition distortion is the main target of this paper. Artificial bee colony (ABC) and firefly optimal algorithms are applied for achieving this goal. These algorithms are applied in conjunction with proposed image encoding/decoding and decomposition/decompression algorithms. The encoding/decoding algorithms depend on binary image, Huffman, and hierarchical trees. In addition, the decompression algorithms use real dual-tree transform, Hilbert transform, real a trou transform, and Gaussian pyramidal transform. A fitness function (FF) that correlates to compression ratio and image quality is conducted. The OCR with the best radiography image quality is the purpose of the suggested FF. A comparison between the optimized compressed ratio of x-ray and neutron radiography images for both optimization techniques is demonstrated. The proposed algorithms are validated. For the ABC algorithm, optimum values of 80.3610% and 80.3610% are fulfilled for x-ray and neutron images via hierarchical trees with Hilbert transforms. An optimum value of 85.333333% is attained by the Huffman algorithm with discrete cosine transform for both images. For the firefly optimization algorithm (FOA), the hierarchical trees with Hilbert transform achieve an optimum value of 97.0499% for both images. The binary image encoding with pyramidal transform gives optimum values of 68.8055% and 77.4566% for x-ray and neutron images, respectively. The FOA is noted to accomplish more advanced results over the ABC algorithm for compressed radiography images. Additionally, the binary image algorithm with a trou decompression provides an optimum value of 76.77% for neutron radiography images. The achieved optimum values of neutron images are better than of x-ray images due to the absorption of more energy by neutron radiation. Robustness and the significant task of the supposed FF are clarified. This confirms the applicability of image compression optimization algorithms with neutron and x-ray radiography images.

SPIE Journal Paper | 9 May 2014

Performance evaluation of quantum well infrared phototransistor instrumentation through modeling

Mohamed El-Tokhy, Imbaby Mahmoud

OE, Vol. 53, Issue 05, 054104, (May 2014) https://doi.org/10.1117/12.10.1117/1.OE.53.5.054104

KEYWORDS: Quantum wells, Phototransistors, Infrared radiation, Infrared photography, Mathematical modeling, Instrument modeling, Performance modeling, Signal to noise ratio, Optical engineering, Infrared detectors

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SPIE Journal Paper | 1 September 2011

Block diagram modeling of quantum dot infrared photodetectors

Mohamed El-Tokhy, Imbaby Mahmoud, Hussein Konber

OE, Vol. 50, Issue 09, 094004, (September 2011) https://doi.org/10.1117/12.10.1117/1.3626209

KEYWORDS: Electrons, Photodetectors, Quantum dots, Infrared radiation, Infrared photography, Quantum well infrared photodetectors, Thermal modeling, Mathematical modeling, Instrument modeling, Performance modeling

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Proceedings Article | 12 February 2011 Paper

Assessment of tissue optical clearing as a function of glucose concentration using optical coherence tomography

Narendran Sudheendran, Mohamed Mohamed, Mohamad Ghosn, Valery Tuchin, Kirill Larin

Proceedings Volume 7889, 78892A (2011) https://doi.org/10.1117/12.874991

KEYWORDS: Glucose, Optical clearing, Tissue optics, Mirrors, Tissues, Skin, Optical coherence tomography, Gold, Scattering, Biomedical optics

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SPIE Journal Paper | 1 September 2010

Performance improvement of quantum well infrared photodetectors through modeling

Mohamed El-Tokhy, Imbaby Mahmoud, Hussein Konber

JNP, Vol. 4, Issue 01, 043518, (September 2010) https://doi.org/10.1117/12.10.1117/1.3502660

KEYWORDS: Quantum wells, Quantum well infrared photodetectors, Photodetectors, Electron transport, Infrared radiation, Performance modeling, Mathematical modeling, Sensors, Thermal modeling, Systems modeling

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Showing 5 of 6 publications

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