Image Perception Wavelet Simulation and Enhancement for the Visually Impaired.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This research delves into the area of image enhancement for the visually impaired. Binocular macular degeneration a visual impairment, affects many Americans since this condition could not be corrected with conventional glasses the literature suggested using an enhancement system which used a pre-emphasis algorithm to enhance the input image for output to the observer. The work of Dr. Eli Peli, a pioneer in the field of image enhancement, is examine and reproduced. Since his work concentrated mainly on frequency analysis of images, the bulk of this research involves using discrete wavelet analysis to augment that work. A biorthogonal wavelet set is used to enhance images. That same wavelet set is used to provide a simulation of a persons perception of an image based upon that person contrast sensitivity function. The wavelet enhancement follows Dr. Pelis method of enhancement using a modified pre-emphasis filter. The wavelet enhancement results are similar to that technique, with the most notable difference being that wavelet enhancements tend to accentuate the horizontal and vertical details of the image more than the spatial frequency concentric filter techniques outlined by Peli and others. The perception simulations use wavelet analysis and are based on the work accomplished by Peli concerning local band-limited contrast, with the frequency analysis of that work giving way to a wavelet analysis the results here are significantly different than those result seen in the Peli simulation.
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