Paulsen K D, Jiang H
Appl Opt. 1996 Jul 1;35(19):3447-58. doi: 10.1364/AO.35.003447.
Optical image reconstruction in heterogeneous turbid media is sensitive to noise, especially when the signal-to-noise ratio of a measurement system is low. A total-variation-minimization-based iterative algorithm is described in this paper that enhances the quality of reconstructed images with frequency-domain data over that obtained previously with a regularized least-squares approach. Simulation experiments in an 8.6-cm-diameter circular heterogeneous region with low- and high-contrast levels between the target and the background show that the quality of the reconstructed images can be improved considerably when total-variation minimization is included. These simulated results are further verified and confirmed by images reconstructed from experimental data by the use of the same geometry and optically tissue-equivalent phantoms. Measures of imaging performance, including the location, size, and shape of the reconstructed heterogeneity, along with absolute errors in the predicted optical-property values are used to quantify the enhancements afforded by this new approach to optical image reconstruction with diffuse light. The results show improvements of up to 5 mm in terms of geometric information and an order of magnitude or more decrease in the absolute errors in the reconstructed optical-property values for the test cases examined.
非均匀浑浊介质中的光学图像重建对噪声敏感，尤其是当测量系统的信噪比很低时。本文描述了一种基于总变差最小化的迭代算法，该算法利用频域数据提高重建图像的质量，优于先前使用正则化最小二乘法获得的图像质量。在直径为8.6厘米的圆形非均匀区域中进行的模拟实验，目标与背景之间具有低对比度和高对比度水平，结果表明，当包含总变差最小化时，重建图像的质量可以得到显著改善。通过使用相同的几何形状和光学组织等效体模从实验数据重建的图像，进一步验证和确认了这些模拟结果。成像性能的测量，包括重建的非均匀性的位置、大小和形状，以及预测光学特性值中的绝对误差，用于量化这种新的漫射光光学图像重建方法所带来的增强效果。结果表明，在所研究的测试案例中，几何信息方面的改进高达5毫米，重建光学特性值的绝对误差降低了一个数量级或更多。
