Lossless compression of JPEG coded photo albums
The explosion in digital photography poses a significant challenge when it comes to photo storage for both personal devices and the Internet. In this paper, we propose a novel lossless compression method to further reduce the storage size of a set of JPEG coded correlated images. In this method, we propose jointly removing the inter-image redundancy in the feature, spatial, and frequency domains. For each album, we first organize the images into a pseudo video by minimizing the global predictive cost in the feature domain. We then introduce a disparity compensation method to enhance the spatial correlation between images. Finally, the redundancy between the compensated signal and the corresponding target image is adaptively reduced in the frequency domain. Moreover, our proposed scheme is able to losslessly recover not only raw images but also JPEG files. Experimental results demonstrate the efficiency of our proposed lossless compression, which achieves more than 12% bit-saving on average compared with JPEG coded albums.