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Proceedings Paper

Effects of the source, surface, and sensor couplings and colorimetric of laser speckle pattern on the performance of optical imaging system
Author(s): M. Darwiesh; Ashraf F. El-Sherif; Hatem El-Ghandour; Hussein A. Aly; A. M. Mokhtar
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Paper Abstract

Optical imaging systems are widely used in different applications include tracking for portable scanners; input pointing devices for laptop computers, cell phones, and cameras, fingerprint-identification scanners, optical navigation for target tracking, and in optical computer mouse. We presented an experimental work to measure and analyze the laser speckle pattern (LSP) produced from different optical sources (i.e. various color LEDs, 3 mW diode laser, and 10mW He-Ne laser) with different produced operating surfaces (Gabor hologram diffusers), and how they affects the performance of the optical imaging systems; speckle size and signal-to-noise ratio (signal is represented by the patches of the speckles that contain or carry information, and noise is represented by the whole remaining part of the selected image). The theoretical and experimental studies of the colorimetry (color correction is done in the color images captured by the optical imaging system to produce realistic color images which contains most of the information in the image by selecting suitable gray scale which contains most of the informative data in the image, this is done by calculating the accurate Red-Green-Blue (RGB) color components making use of the measured spectrum for light sources, and color matching functions of International Telecommunication Organization (ITU-R709) for CRT phosphorus, Tirinton-SONY Model ) for the used optical sources are investigated and introduced to present the relations between the signal-to-noise ratios with different diffusers for each light source. The source surface coupling has been discussed and concludes that the performance of the optical imaging system for certain source varies from worst to best based on the operating surface. The sensor /surface coupling has been studied and discussed for the case of He-Ne laser and concludes the speckle size is ranged from 4.59 to 4.62 μm, which are slightly different or approximately the same for all produced diffusers (which satisfies the fact that the speckle size is independent on the illuminating surface). But, the calculated value of signal-tonoise ratio takes different values ranged from 0.71 to 0.92 for different diffuser. This means that the surface texture affects the performance of the optical sensor because, all images captured for all diffusers under the same conditions [same source (He-Ne laser), same distances of the experimental set-up, and the same sensor (CCD camera)].

Paper Details

Date Published: 21 February 2011
PDF: 21 pages
Proc. SPIE 7920, Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVI, 792005 (21 February 2011); doi: 10.1117/12.874074
Show Author Affiliations
M. Darwiesh, Military Technical College (Egypt)
Ashraf F. El-Sherif, Military Technical College (Egypt)
Hatem El-Ghandour, Ain Shams Univ. (Egypt)
Hussein A. Aly, Military Technical College (Egypt)
A. M. Mokhtar, Military Technical College (Egypt)

Published in SPIE Proceedings Vol. 7920:
Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVI
Bo Gu; Guido Hennig; Xianfan Xu; Hiroyuki Niino, Editor(s)

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