A lossless image compression algorithm using duplication free run-length coding

In this paper, a novel lossless image compression algorithm using duplication free run-length coding (RLC) is proposed. An entropy rule-based generative coding method is proposed to generate variable length codewords, and the resulting codewords are utilized to encode image where codewords are assigned to pixel intensity values based on their probability of occurrence. These codewords can be generated in a way so that pixel intensity level could be distinguished from run in which case this differentiability is required in the traditional RLC. The proposed method overcomes the duplication problem in the traditional RLC algorithms. To the best of our knowledge, the proposed method is the first RLC algorithm that encodes the case of two consecutive pixels of the same intensity into a single codeword, hence gaining on compression. Also, the number of occurrence (i.e., run) that can be encoded in a single codeword is infinite. Experiments were carried out using standard test images to verify the basic performances of the proposed method. The results suggest that the proposed method does not cause an increase in the file size of the encoded images, and it achieves better compression ratios when compared to the traditional RLC algorithms.