Efficient Lossless Image Compression Based on CWT

Image compression is a technique used to reduce the storage required to save an image. The existing image coding methods cannot support content based image compression and enlargement for arbitrary resolution display devices. In multimedia communications, image retargeting is generally required at the user end. The work presented in this paper addresses the increasing demand of visual signal delivery to terminals with arbitrary resolutions, without heavy computational burden to the receiving end. In this paper, the principle of seam carving and wavelet based SPIHT codec are used. For each input image, block based seam energy map is generated at the encoder side and the multilevel integer wavelet transform is performed. At the decoder side, the end user has the ultimate choice for the spatial scalability without the need to examine the visual content an image with arbitrary aspect ratio can be reconstructed in a content-aware manner based upon the side information of the seam energy map. The final result show that, for the end users, the received images with an arbitrary resolution preserve important and sensitive content while achieving high coding efficiency for transmission.