Leveraging Redundancy in Feature for Efficient Learned Image Compression

In recent years, with the development of the field of learned image compression, numerous models with excellent rate-distortion performance have emerged. However, the considerable computational complexity inherent in these models poses challenges for their practical deployment. In this paper, we investigate feature redundancy in learned image compression (LIC) algorithms for efficient feature extraction and introduce an efficient and lightweight LIC framework. Specifically, we explore the existence of a large number of similar features in the network. Subsequently, we design effective feature extraction modules across various levels, such as layer and block. In addition, based on the fact that the role of the codec's encoder is to remove redundancy and the decoder is to reconstruct, we propose an asynchronous feature fusion block. This fusion block incorporates an "edge smoothing" operator in the encoder and an "edge enhancement" operator in the decoder. Our methodology strikes an ideal balance between rate-distortion performance and efficiency. The experimental results indicate that our approach necessitates only 310KMac/pixel computation and 9.5M parameters, while in terms of performance, our method achieves a 20.7% BD-rate advantage over BPG on Kodak data, mirroring VVC's performance. Compared to other learned image compression algorithms with SOTA performance, our method has a great advantage in terms of computation/parameter count.