A Lossless Joint Image Compression Using Wavelet Decomposition and Hierarchical Tree Encoding

Wavelet decomposition and hierarchical tree encoding can be used to achieve joint lossless image encryption and compression simultaneously. It is done on the basis of BLAKE-2 Hash algorithm, Integer Wavelet Transformation (IWT) and Set Partitioning In Hierarchical Trees (SPRIT) encoding. BLAKE-2 Hashing algorithm is used to generate sensitive keys from the input image and it results different key values for different images. BLAKE algorithm is very sensitive to changes occurred in the input. In IWT, images are decomposed in to various layers and hence are more immune to attacks. One of the most powerful image compression algorithm used to produce an embedded bit stream form that has the best reconstructed images which shows a significant perceptual improvement as well as an increased PSNR is SPRIT. SPRIT encoding never uses a code book and hence there is no burden to send the coded book while transmission. By combining all the three methods we obtained a decrypted image with high security, good lossless compression performance, high PSNR value and a better quality factor.