Design and Implementation of Real-time Image Processing of the Low Vision Aid Based on FPGA
| Autor: | Ji-Min Li, 李吉民 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 Objective：To develop a customer-made portable low-vision-assistant device is the goal that can do image processing in hardware so that the peoples with low-vision can view enhanced images without the needs of image-magnification. By wearing this device, the visual sensitivity and distinguish ability for things can be improved for low-vision subjects. Method：Technique of contrast sensitivity measurement was employed to evaluate the visual function for the subjects with low-vision so that their contrast sensitivity functions (CSF) were obtained and compared to the normals. The differences between the two were then converted to visual degradation transfer function (VDTF) so that the deficiencies in the domain of spatial frequency of the low-vision subjects could be obtained. Through the algorithm of image enhancement that incorporated with FPGA (Field Programmable Gate Array, ALTERA Cyclone® II EP2C70), which can integrate system on a programmable chip, a high-speed image enhancement system can be implemented. Result：The results of image enhancement through the application of FPGA showed that when the system clock ran at 27 MHz, then for an image with size of 640×480 and 8-bit resolution that was separated into five frequency bands with individual processing algorithm, the enhanced-image output can reach 64 frames/sec. Conclusion：Instead of traditional theory of magnification, image enhancement through hardware technique in this study can provide an effective way of reality. Compared to the way of software in image processing, the way of the approach by hardware can provide real time information with enhanced images. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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