Szász-type operators can be constructed by a Poisson process. The purpose of this paper is to derive the converse result in connection with Szász-type operators by Steckin-Marchaud-type inequalities and new Ditzian modulus of continuity. The degree of approximation on deterministic signals is also given.
In this paper,the explicit estimates of central moments for one kind of exponential-type operators are derived.The estimates play an essential role in studying the explicit approximation properties of this family of operators.Using the proposed method,the results of Ditzian and Totik in 1987,Guo and Qi in 2007,and Mahmudov in 2010 can be improved respectively.
引入了压缩感知(Compressed sensing,CS)理论,给出了在获取局部二维离散余弦变换(Discrete cosine transform,DCT)系数的基础上高质量地编码与重构图像的新方法.研究了在无量化和有量化情况下,基于局部DCT系数的图像CS最小全变差重构算法.在对DCT系数进行量化的过程中得到含噪的局部DCT系数,在此基础上设计了能完成CS重构的图像编解码一般流程,并构建了实际应用系统.实验结果表明,对于稀疏性较强的图像,在图像编解码系统中结合CS理论与方法能得到高质量的重构图像,与传统的直接反离散余弦变换(Inverse DCT,IDCT)方法相比,峰值信噪比(Peak signal to noiseratio,PSNR)最大能提高5dB以上,对于一般图像,PSNR也有较大提高.
