The influence of speckle noise in degrading performance of a reader for electro-optically reading a multiple element symbol is reduced by constructing wavelets for each element width, correlating each wavelet with a differentiated signal derived from light scattered from the symbol to obtain a correlated...http://www.google.com.tw/patents/US7124949?utm_source=gb-gplus-share專利 US7124949 - Reducing speckle noise in electro-optical readers
