arXiv Computer Vision

Joint Semantic-Channel Coding and Modulation for Generative Image Transmission

The paper introduces SemQAM, a joint semantic-channel coding and modulation framework for generative image transmission that converts source representations directly into modulated QAM symbols. By vector‑quantizing latent features and mapping each index to a QAM symbol, SemQAM allows channel impairments to influence codebook learning and employs conditional expectations of received codewords to mitigate error propagation in autoregressive decoding. Experiments demonstrate that SemQAM-C matches or surpasses conventional source coding methods while reducing channel uses by 18.57% compared to separated schemes, highlighting its efficiency and effectiveness in joint coding.

arXiv Machine Learning
Aug 18

In-Context Source and Channel Coding

arXiv:2601. 10267v2 Announce Type: replace Abstract: Separate Source-Channel Coding (SSCC) remains attractive for text transmission due to its modularity and compatibility with mature entropy coders and powerful channel codes.

By Ziqiong Wang, Tianqi Ren, Rongpeng Li, Zhifeng Zhao, Honggang Zhang
arXiv Computer Vision
Oct 1

Rethinking Generative Image Compression at Extremely Low Bitrates

The paper introduces RAE-CoD, a diffusion-based compression method that operates in a representation autoencoder space to preserve recognizable content even at extremely low bitrates. It addresses the problem of semantic collapse observed in existing codecs when the bitrate approaches zero, showing that reconstruction losses conflict with semantic objectives and that VAE diffusion models lose efficiency in preserving semantics. Experiments on MSCOCO-30K demonstrate that RAE-CoD outperforms competitors, reducing VFM feature MSE and Fréchet Distance ratios by at least 25.7% and 69.1% at 0.001–0.008 bpp while maintaining stable recognizability and quality.

By Tianyu Zhang, Zhaoyang Jia, Houqiang Li, Dong Liu
arXiv Computer Vision
Sep 4

Tree-Structured Vector Quantization For Efficient And Progressive Image Compression

Tree-VQ introduces a progressive tree‑structured vector quantization framework for learned image compression, organizing discrete codewords in a hierarchical binary tree where each latent token is represented by a routed root‑to‑leaf path. Every prefix of this path yields a valid quantized representation, enabling coarse reconstructions from shallow nodes and successive refinements from deeper nodes. The method incorporates a prefix‑compatible tree entropy model, rate‑aware refinement scheduling, and hierarchical prefix supervision to achieve efficient, low‑latency compression with superior perceptual quality and fewer parameters compared to existing approaches.

By Xinkun Wang, Tianyi Xu, Qingyu Luo, Mingming Ma, Changzhe Jiao, Fu Li, Yi Niu
arXiv Computer Vision
Sep 7

Multi-scale Image Representation Compression

The paper introduces MIRC, an overfitted image codec that quantizes and entropy‑codes all components—including latents, synthesis network, and entropy models—within a single end‑to‑end rate‑distortion framework inspired by NVRC. It adds a multi‑scale representation with cross‑stage parameter sharing to capture cross‑scale redundancy, yielding a 10.5 % BD‑rate saving over VVC on the CLIC2020 professional set. MIRC offers multiple configurations ranging from 1.2 to 2.9 kMAC per pixel, allowing decoding complexity to be tuned to deployment needs.

By Tianhao Peng, Ho Man Kwan, Fan Zhang, Shan Liu, David Bull