Continuous Patch Stitching for Block-wise Image Compression

TL;DR

This paper introduces a continuous patch stitching framework for block-wise image compression that reduces computational resources and eliminates block artifacts, enabling seamless high-quality image compression.

Contribution

It proposes a novel CPS framework with padding-free operations and a stitching strategy, improving efficiency and artifact removal in block-wise learned image compression.

Findings

Achieves state-of-the-art performance on image compression benchmarks.

Requires less than half the computational resources of existing models.

Effectively eliminates block artifacts in high-resolution image compression.

Abstract

Most recently, learned image compression methods have outpaced traditional hand-crafted standard codecs. However, their inference typically requires to input the whole image at the cost of heavy computing resources, especially for high-resolution image compression; otherwise, the block artefact can exist when compressed by blocks within existing learned image compression methods. To address this issue, we propose a novel continuous patch stitching (CPS) framework for block-wise image compression that is able to achieve seamlessly patch stitching and mathematically eliminate block artefact, thus capable of significantly reducing the required computing resources when compressing images. More specifically, the proposed CPS framework is achieved by padding-free operations throughout, with a newly established parallel overlapping stitching strategy to provide a general upper bound for ensuring the continuity. Upon this, we further propose functional residual blocks with even-sized kernels to achieve down-sampling and up-sampling, together with bottleneck residual blocks retaining feature size to increase network depth. Experimental results demonstrate that our CPS framework achieves the state-of-the-art performance against existing baselines, whilst requiring less than half of computing resources of existing models. Our code shall be released upon acceptance.