图像视频信号的压缩采样与稀疏重建
摘要
Vision sensors usually do not account for the physical process of imaging and they acquire image/video samples at the Nyquist rate. The Nyquist rate is significantly higher than the effective dimensions of an image/video, and consequently compression is essential for the image/video prior to storage or transmission. The emerging Compressive Sensing (CS) theory states that a signal can be perfectly reconstructed, or can be robustly approximated in the presence of noise, using a few random measurements, provided that it is sparse in some linear transform domain. CS is the theoretical foundation for capturing a signal with effective information dimensions, and thus represents an unprecedented breakthrough in many fields such as sampling, processing, and recognition of image/video. We review the fundamental problems of CS for image/video including compressive sampling, sparse reconstruction models, and algorithms for the models. For compressive sampling, the construction of random and structural measurement matrices are considered separately and the performance of these two kinds of matrices is evaluated. For sparse reconstruction, models are classified as analysis-based or synthesisbased reconstruction models by the sparse representation prior, features of which are presented. The optimization models can be considered as constrained and unconstrained optimization problems. Some feasible algorithms for these two kinds of optimization problems are explained in detail and the performance of the algorithms is given. In addition, several challenges of compressive sensing technology are presented and future work is discussed.