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D Zur, M Belkin, Y Moisseiev, G Ben-Simon, S Ullman; Improving the AMD Perception by Image Enhancement Technique that Makes Use of the Filling-in Effect . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3911.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To improve the visual performances of the Age-related Macular Degeneration (AMD) individuals by presenting them enhanced images that make use of the observer's filling-in mechanism. Methods: Age-related Macular Degeneration (AMD) damages the retina and causes retinal scotomas, regions at which visual stimulation is not available. In spite of these blind spots, the images perceived by the patients are usually continuous, and at the same time distorted in certain ways. The abnormal perception cannot be corrected by current clinical or optical means, and prevents many AMD individuals from performing ordinary tasks, such as watching TV and reading. The results of our four years research shows that the main mechanism responsible for the AMD perceptual effects is a cortical «filling-in» process that operates on lines, edges, and texture patterns. The filling-in process causes partial completion of the images across the scotomas and induces the perception of continuous image. We herein present a new technique of image enhancement that makes use of the filling-in mechanism of the AMD observer, enabling him/her to perceive the images better. For example, making the lines and edges in the image sparser and emphasizing only the relevant ones make the perception easier. On the other hand, making two dimensional texture pattern denser often enables the perception of complete pattern. We tested the efficiency of the technique by measuring the minimum image size that enables AMD subjects to recognize familiar faces, objects, and to read. In addition, we measured the visual performances and impression when watching enhanced video images. We compared the results of 37 subjects with their visual perception and performances when watching the original and natural Images. Results: We found that AMD subjects can recognize familiar objects and read in enhanced images that are in average smaller than 50% of the minimum size required to recognize and read in the original images. More than 70% of the subjects that had difficulties in watching the original video images, preferred to watch the enhanced ones. As the visual acuity of the AMD subjects decreased, the percentage of preference for the enhanced images increased. Conclusion: Enhancing the relevant features of the image, in a way that enables them to be filled-in better, significantly improves the perception of the AMD individuals. The implementation of the technique can lead to a new medical apparatus that will enable the patients to watch TV and read more easily.
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