基于离散余弦变换域采样和重建的低码率图像压缩算法  

Low Bit Rate Image Compression via Down-sampling and Reconstruction in DCT

作　　者：吴强[1] 何小海[1] 熊淑华[1] 陈洪刚[1] 卿粼波[1] 

机构地区：[1]四川大学电子信息学院,成都610065

出　　处：《科学技术与工程》2016年第5期187-192,共6页Science Technology and Engineering

基　　金：国家自然科学基金资助项目(61471248);四川省科技计划项目(2015JY0189);四川省教育厅2014年研究生教育改革创新项目(2014-教-034)资助

摘　　要：构建了一种基于离散余弦变换(discrete cosine transform,DCT)域采样和超分辨率(super resolution,SR)重建的低码率图像压缩编码算法。在编码端对原始图像进行分块离散余弦变换(DCT),并提取每个DCT系数块的低频系数,然后再反变换到空间域,从而得到在DCT域下采样的低分辨率(low resolution,LR)图像块。用JPEG标准对下采样图像块编解码后,采用基于学习的方法恢复DCT域高频系数,重建出高分辨率(high resolution,HR)的图像。实验结果表明,在码率较低的情况下,算法比JPEG编码标准具有更好的率失真性能;同时,在相同码率下,算法重建的解码图像视觉效果更好。An image Compression algorithm is presented via combining the discrete cosine transformation （DCT） domain down-sampling and super-resolution reconstruction. Firstly, the image is first divided into non-over- lapping blocks, and each block is transformed by DCT. Secondly, low frequency coefficients of each block are ex- tracted and inverse-transformed to generate the down-sampled low resolution image. After the down-sampled image is compressed and decompressed by the standard JPEG. the high freauencv coefficients are recovered by the learn-ing-based method in the spatial domain. Experimental results show that the compression algorithm presented has better rate-distortion performance than JPEG at low bit rate, and the visual quality of decompressed image by our method is also better at the same coding bit rate.

关 键 词：图像编码 低码率 离散余弦变换(DCT) 采样 超分辨率重建 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]