Implementation of light spot positioning system using FPGA-based image module and its applications

• Main Authors: Chen-Neng Fan, 范振能
• Other Authors: Wen-Kai Kuo
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/5bh9pb

碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 95 === In this thesis, we propose a FPGA (Field Programmable Gate Array) chip module to implement the light spot positioning system and its applications. We use image sensor to capture two successive images by controlling the power of laser pointer or LED (light emitter diode) ON and OFF. Then a simple subtraction operation is used to eliminate the background and avoid the light noise. By this method, we can get a resulted image with noting but a clear light spot and it becomes very easy to locate its coordinate. We also design an algorithm suitable for FPGA-based system to locate the coordinate of light spot center. The conventional PC-based light spot locating method records all the coordinates of the spot pixel in the image, then compute the average center to get the coordinate of the light spot. Our algorithm uses the replaced method to save memory and logic elements in the FPGA module. The total used logic elements (LE) of our algorithm are only 16.6% of that of the conventional method. To interact with the computer, we use FPGA to control the USB micro-controller in a commercial USB mouse to make the compute cursor to follow the light spot motion. Besides, we put a diffractive optical element (DOE) in front of the image sensor to blur the background image and transform the light spot into a diffractive circle pattern. This approach can eliminate the subtraction noise caused by the two successive images without similar back-ground images.