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UBC Theses and Dissertations

The input stage of a TV-computer reading system for the blind Tsang, Robert Chuen Bong

Abstract

The input stage of a TV-computer reading system has been built using state-of-the-art integrated circuits. A stroboscopic sampling method is used. Programs are developed to rearrange the input data for later processing. The system is also available to work as an image enlarger for people with low-vision. Judging from the appearance of the final displays, the signal-to-noise ratio is acceptable. The possibility of incorporating an automatic focus device is examined and an algorithm is developed to this end. Best focus is obtained by adjusting the camera's lens to maximize the ‘T’ function which is related to the differences in the greyness between samples. The hardware and software are developed for the TV camera to work with a PDP-12 computer as an input system. Suggestions for further improvements of the system are also included.

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