若感兴趣区域具有分片光滑或多项式特征,则可通过全变分(TV)最小化进行精确内重建。目标函数TV最小化过程可通过梯度下降法以其负梯度方向为搜索方向,经过多次迭代优化实现。为提高TV最小化重建的效率,提出一种天牛须搜索(BAS)和梯度下降相结合的寻求最优解方向的方法。在TV最小化过程中根据生成的随机数和阈值选择梯度下降方向或由个体“左右须”检测到的最优解方向进行迭代。仿真实验和实际实验结果表明,本文算法收敛速度较快,重建效果更好。

Region of interest is sliced smooth or polynomial, then accurate internal reconstruction can be performed by total variation (TV) minimization. The solution of TV minimization usually adopts the gradient descent method, taking the negative gradient of the objective function as the search direction, and then optimizes iteratively the objective function. In order to improve the efficiency of TV minimizing, this paper proposes a method to find the optimal solution direction by combining beetle antennae search (BAS) and gradient descent. The method selects the gradient descent direction or the optimal solution direction which is based on the individual “left and right whiskers” to iterate, according to the generated random number and threshold during the TV minimization process. The simulation experiment and the actual experiment show that the proposed algorithm has fast convergence speed and good reconstruction effect.