基于小波变换的图像边缘检测

Edge detection image based on wavelet transform

提出了一种新的基于小波变换的多尺度多分辨率特性的边缘检测方法。分别利用不同尺度小波变换后的水平方向、垂直方向和对角线方向高频信息 ,根据李氏指数与小波变换关系 ,采用零交叉检测方法和极大值在不同尺度下传播的特性 ,检测出图像在 3个方向的极大值。对不同尺度不同方向高频子图像 ,首先采用平均值法确定阈值 ,去除震荡噪声 ,然后对不同方向高频子图像合成的图像 ,根据最大类间方差法 ,计算其阈值 ,求出极大值 ,最后从这 3个方向的极大值中确定出最大值。实验结果表明 ,检测出图像的边缘结果非常理想。

Based on multi-scale and multi-resolution of wavelet transform a new algorithm of edge detection has been presented. This algorithm separately utilizes high frequency information of horizontal, vertical and diagonal directions of wavelet transform under different scales. According to relation of Lipschitz exponent and wavelet transform, the properties of cross-zero and propagation under different scales are utilized to determine local max in three directions. Firstly, to the subimage of different scales and directions the method of average threshod is utilized to determine the threshold and to denoise. Secondly to the synthesized image of different orientation subimage the method of OSTU is utilized to compute the threshold to max. At last it determines the maximal one of those in three orientation. The experiment presents that the results of edge detection are very good.