一种改进的梯度加速Landweber算法及其在ECT图像重建中的应用

图像重建算法是电容层析成像技术(electrical capacitance tomography,ECT)在工业应用中的关键.Landweber迭代算法在图像重建的精度和速度上取得了较好的折衷性,但其收敛速度较慢,且迭代后期具有不稳定性,无明确的迭代停止准则.提出一种改进的梯度加速Landweber迭代算法,依据级数...

Application of an improved gradient accelerated landweberalgorithm in ECT image reconstruction

Image reconstruction algorithm is the key to the industrial application of electrical capacitance tomography. The Landweberiterative algorithm has achieved a good compromise in the accuracy and speed of image reconstruction, but its convergence speed is slow,and the late iteration is unstable, there is no clear iteration stop criterion. In this paper, an improved gradient accelerated Landweberiterative algorithm is proposed, based on the series theory, the gradient accelerated Landweber iterative algorithm is deeply analyzed, anew iterative formula is obtained by constructing the residual matrix and adding constraint factors, and it is applied to ECT Imagereconstruction. Numerical simulation results show that the relative error and correlation coefficient of the improved algorithm can convergeto a certain value after less iteration steps, and has a clear iteration stop criterion. Moreover, for most flow patterns, the reconstructedimages are closer to the original flow patterns in subjective quality, which verifies the stability and effectiveness of the improvedalgorithm.