参数自适应调整的稀疏贝叶斯重构算法
doi: 10.3724/SP.J.1146.2013.00629
Bayesian Sparse Reconstruction with Adaptive Parameters Adjustment
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摘要: 稀疏表示模型中的正则化参数由未知的噪声和稀疏度共同决定,该参数的设置直接影响稀疏重构性能的好坏。然而目前稀疏表示问题优化求解算法或依靠主观、或依靠相关先验信息、或经过实验设置该参数,均无法自适应地设置调整该参数。针对这一问题,该文提出一种无需先验信息的参数自动调整的稀疏贝叶斯学习算法。首先对模型中各参数进行概率建模,然后在贝叶斯学习的框架下将参数设置及稀疏求解问题转化为一系列混合L1范数与加权L2范数之和的凸优化问题,最终通过迭代优化得到参数设置和问题求解。由理论推导和仿真实验可知,已知理想参数时,该算法与其它非自动设置参数的迭代重加权算法性能相当,甚至更优;在理想参数未知时,该算法的重构性能要明显优于其它算法。Abstract: The regularization parameter of sparse representation model is determined by the unknown noise and sparsity. Meanwhile, it can directly affect the performances of sparsity reconstruction. However, the optimization algorithm of sparsity representation issue, which is solved with parameter setting by expert reasoning, priori knowledge or experiments, can not set the parameter adaptively. In order to solve the issue, the sparsity Bayesian learning algorithm which can set the parameter adaptively without priori knowledge is proposed. Firstly, the parameters in the model is constructed with the probability. Secondly, on the basis of the framework of Bayesian learning, the issue of parameter setting and sparsity resolving is transformed to the convex optimization issue which is the addition of a series of mixture L1 normal and the weighted L2 normal. Finally, the parameter setting and sparsity resolving are achieved by the iterative optimization. Theoretical analysis and simulations show that the proposed algorithm is competitive and even better compared with other parameter non-adjusted automatically iterative reweighted algorithms when ideal parameter is known, and the reconstruction performance of the proposed algorithm is significantly better than the other algorithms when choosing the non-ideal parameters.
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