Bogazici University, Institute of Biomedical Engineering, Istanbul, 34684, Turkey.
J Biomed Opt. 2011 Aug;16(8):086010. doi: 10.1117/1.3615238.
A method to locate an absorber embedded in a semi-infinite turbid medium by spatially-resolved continuous-wave (SRCW) diffuse reflectance measurements is introduced. The depth of the absorber is assessed by single wavelength SRCW diffuse reflectance measurements by two detectors in a radial row. The ratio of perturbations introduced by the defect at two detectors is used to be matched with the ratio-versus-depth curve, which are generated by approximate formulas of continuous wave diffuse reflectance. The error due to approximation and the error in depth assessment are studied for different cases revealing favorable source-detector placements with respect to planar position of the defect. The effect of lateral displacement of the source with respect to defect is studied. A strategy to overcome errors introduced by erroneous prediction of background medium optical properties is suggested. Theoretical results indicate that the depth of the absorber can be obtained with 0.1 mm precision independent of its absorption coefficient and its size for the values chosen in the study. The approach is tested experimentally and it is observed that theoretical results fit with experimental data.
本文提出了一种通过空间分辨连续波（SRCW）漫反射测量来定位半无限混浊介质中吸收体的方法。通过在径向行中的两个探测器进行单波长 SRCW 漫反射测量，可以评估吸收体的深度。通过将两个探测器处的缺陷引起的扰动比与通过连续波漫反射近似公式生成的比-深度曲线进行匹配，来评估缺陷的深度。针对不同情况研究了由于近似和深度评估误差引起的误差，揭示了相对于缺陷平面位置的有利源-探测器放置。研究了源相对于缺陷的横向位移的影响。提出了一种克服背景介质光学性质预测错误引入的误差的策略。理论结果表明，对于所研究的吸收体的吸收系数和尺寸值，可以以 0.1mm 的精度获得吸收体的深度。该方法已通过实验进行了测试，并且观察到理论结果与实验数据吻合。
