基于小波包特征提取的车牌字符识别，是一片期刊论文，还不错的，可以学习-Feature extraction based on wavelet packet license plate character recognition is a journal articles, but also good, you can learn

基于小波变换的图像纹理特征提取方法及其应用-A Method of Image Texture Feature Analysis Based on Wavelet Decomposition and its Application