Real-time lossless image compression by dynamic Huffman coding hardware implementation

Abstract

Over the decades, implementing information technology (IT) has become increasingly common, equating to an increasing amount of data that needs to be stored, creating a massive challenge in data storage. Using a large storage capacity can solve the problem of the file size. However, this method is costly in terms of both capacity and bandwidth. One possible method is data compression, which significantly reduces the file size. With the development of IT and increasing computing capacity, data compression is becoming more and more widespread in many fields, such as broadcast television, aircraft, computer transmission, and medical imaging. In this work, we introduce an image compression algorithm based on the Huffman coding algorithm and use linear techniques to increase image compression efficiency. Besides, we replace 8-bit pixel-by-pixel compression by dividing one pixel into two 4-bit halves to save hardware capacity (because only 4-bit for each input) and optimize run time (because the number of different inputs is less). The goal is to reduce the image’s complexity, increase the data’s repetition rate, reduce the compression time, and increase the image compression efficiency. A hardware accelerator is designed and implemented on the Virtex-7 VC707 FPGA to make it work in real-time. The achieved average compression ratio is 3,467. Hardware design achieves a maximum frequency of 125 MHz.