摘要
为克服常用滤波模板的缺陷,消除传统图像滤波中存在的振铃现象和方块效应,提出了任意正交变换下的2维加窗全相位滤波算法。在严格证明任意正交变换下的2维全相位模板的计算通式基础上,进一步推导出傅里叶变换下的加窗全相位模板的简化公式。通过对亚奈图像的恢复实验证明:相比于反傅氏变换法生成的模板,用全相位DFT(d iscrete Fourier transform)模板恢复出的图像PSNR(峰值信噪比)值要高出7dB以上,且消除了振铃现象。通过实验还证明,用全相位DCT(d iscrete cosine transform)模板滤波可完全消除传统分块滤波中的方块效应。
To overcome commonly-used filtering template' s drawback and remove the ringing artifact& block effect in conventional image filtering, this paper presents 2D all-phase window filtering under arbitrary orthogonal transform. Based on the general calculating formula of 2D all-phase template under arbitrary orthogonal transform, the concise formula of all- phase template with window under DFT is deduced. The restoration experiment on the sub-sampled image proves that: compared with the template constructed by IDFT, the PSNR of the image restored by all kinds of all-phase template is above 7dB higher and ringing artifact can be eliminated. Another experiment shows that block effect in conventional block filtering can be completely removed by employing 2D all-phase DCT template.
出处
《中国图象图形学报》
CSCD
北大核心
2006年第6期811-817,共7页
Journal of Image and Graphics
关键词
模板
2维加窗全相位滤波
振铃现象
方块效应
任意正交变换
template, 2D all-phase filtering with window, ringing artifact, block artifact, arbitrary orthogonal transform