摘要：

针对小波域图像放大出现的伪吉普斯现象和虚假边缘问题,提出一种新的小波域图像放大算法。对原始图像进行一级小波变换,根据各高频子带的方向特点,确定高频子带系数在放大子带中的布放位置。给出基于边缘方向的高频系数插值方法,计算空白像素的高频系数。将线性变换的原始图像作为放大后的低频子带,结合放大后的3个高频子带进行小波反变换,得到基于小波变换的放大图像。实验结果表明,该算法可有效克服由于小波变换缺乏平移不变性造成的伪吉普斯现象,避免产生虚假边缘。

关键词: 图像放大, 小波变换, 高频子带放大, 伪吉普斯现象, 虚假边缘

Abstract: In order to suppress Pseudo-Gibbs phenomena and remove false edges in image magnification of Wavelet domain,an image magnification algorithm in Wavelet domain is presented.After the original image is decomposed by one level Wavelet transform,an accurate location and placement method of high frequency coefficients in magnified high frequency subbands is given according to the orientation characteristic of high frequency subbands.An edge direction based interpolation method is proposed to determine the value of high frequency coefficient at the blank spaces of pixels.The magnified image is obtained by inversing Wavelet transform on the above magnified three high frequency subbands,and the magnified low frequency subband generated by linear transform of the original image.Experimental results show that the proposed algorithm can effectively remove the Pseudo-Gibbs phenomena due to the shift variance characteristic of wavelet transform,and avoid the generation of false edges.

Key words: image magnification, Wavelet transform, magnification of high frequency subbands, Pseudo-Gibbs phenomena, false edge

中图分类号: 

• TP391