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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)].
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