Some Advances in Optoelectronic Pattern Recognition Using Liquid Crystal Device

• Main Authors: Jian-Shuen Fang, 方建舜
• Other Authors: Chulung Chen
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/60028149075614762397

碩士 === 元智大學 === 電機工程學系 === 90 === In this thesis, the optoelectronic pattern recognition using liquid crystal device is presented. Hybrid Optoelectronic signal processing could be the powerful operation for real-time pattern recognition. Optical pattern recognition can cooperate with electronic computer to fit more flexibility require. To detect target images with equal output correlation peaks, the minimum average correlation energy nonzero order joint transform correlator (MACE-NOJTC) is introduced. The design is carried out using the Lagrange multipliers technique to minimize the average correlation energy for all training set images while constraining the correlation peak value to a user-specified constant. An ideal reference function for the MACE-NOJTC is derived. Correlation results are presented. It is observed that the system has the ability to recognize the rotated image and to locate the image position. The multilevel multi-level quantization reference function (MQRF) is also proposed. The MQRF filters are spatial domain filters using finite quantization levels. They can be implemented at the input spatial light modulator of a joint transform correlator (JTC). The performance of MQRF filters has been tested. We have calculated that the peak to average correlation energy (PACE), peak to sidelobe ratio (PSR), and discrimination ratio (DR). They meliorate as the quantization level increases.