Thummerer G, Mayr G, Haltmeier M, Burgholzer P
Josef Ressel Centre for Thermal NDE of Composites, University of Applied Sciences Upper Austria, Wels, Austria.
Department of Mathematics, University of Innsbruck, Innsbruck, Austria.
Photoacoustics. 2020 Mar 19;19:100175. doi: 10.1016/j.pacs.2020.100175. eCollection 2020 Sep.
Photothermal measurements with an infrared camera enable a fast and contactless part inspection. The main drawback of existing reconstruction methods is the degradation of the spatial resolution with increasing imaging depth, which results in blurred images for deeper lying structures. In this paper, we propose an efficient image reconstruction strategy that allows prior information to be included to overcome the diffusion-based information loss. Following the virtual wave concept, in a first step we reconstruct an acoustic wave field that satisfies the standard wave equation. Therefore, in the second step, stable and efficient reconstruction methods developed for photoacoustic tomography can be used. We compensate for the loss of information in thermal measurements by incorporating the prior information positivity and sparsity. Therefore, we combine circular projections with an iterative regularization scheme. Using simulated and experimental data, this work demonstrates that the quality of the reconstruction from photothermal measurements can be significantly enhanced.
使用红外热像仪进行光热测量能够实现快速且非接触式的部件检测。现有重建方法的主要缺点是随着成像深度增加空间分辨率会下降，这会导致深层结构的图像模糊。在本文中，我们提出了一种有效的图像重建策略，该策略允许纳入先验信息以克服基于扩散的信息损失。遵循虚拟波概念，第一步我们重建一个满足标准波动方程的声波场。因此，在第二步中，可以使用为光声层析成像开发的稳定且高效的重建方法。我们通过纳入先验信息的正性和稀疏性来补偿热测量中的信息损失。因此，我们将圆形投影与迭代正则化方案相结合。利用模拟和实验数据，这项工作表明光热测量重建的质量可以得到显著提高。
