Modified Sparsity Index and Histogram Sorting Based Lossless Image Compression for Medical Images

In medical applications, lossless coding methods are required since loss of any information is usually unacceptable. Integer to integer lifting operations help to implement the lossless compression methods. Medical images are sparser than other natural images, so that by exploiting the sparseness feature, it is possible to achieve maximum compression efficiency. This paper modifies the sparsity index which defines the degree of sparseness of images and it proposes a histogram sorting method which is more efficient than the conventional histogram packing methods in terms of compression ratio.