DVCast: denoising and variable dct for analog visual communications

Recently, analog visual transmission has attracted considerable attention owing to its graceful performance degradation for various wireless channels. In this study, a novel analog visual communications system called Denoising and Variable dct for image multicast (DVCast) is proposed, in which an image denoising algorithm is used to fully utilize spatial correlation; moreover, the variable block size Discrete Cosine Transform (DCT) is used to preserve more correlation information in an image. Obviously, there is a tradeoff between system performance and computing complexity. Therefore, to improve the real-time performance of the proposed system, implementation of Block Matching with 3D filtering (BM3D) and DCT by Graphics Processing Units (GPUs) is introduced. According to DCT block size, i.e., 8 × 8 , 16 × 16 , and 32 × 32 , the schemes D V C a s t 8 , D V C a s t 16 , and D V C a s t 32 , respectively, are designed and implemented. Simulations show that DVCast with larger block size achieves better gain and visual quality than reference schemes. Moreover, it requires less computing time. D V C a s t 32 outperforms conventional digital schemes by approximately 3.51 dB and achieves a 1.12 dB gain over state-of-the-art reference schemes. Furthermore, the analysis shows that DVCast can reduce overhead by at least 75%.