Opt Lett. 2021 Feb 1;46(3):673-676. doi: 10.1364/OL.411187.
Spatial frequency domain imaging can map tissue scattering and absorption properties over a wide field of view, making it useful for clinical applications such as wound assessment and surgical guidance. This technique has previously required the projection of fully characterized illumination patterns. Here, we show that random and unknown speckle illumination can be used to sample the modulation transfer function of tissues at known spatial frequencies, allowing the quantitative mapping of optical properties with simple laser diode illumination. We compute low- and high-spatial frequency response parameters from the local power spectral density for each pixel and use a lookup table to accurately estimate absorption and scattering coefficients in tissue phantoms, in vivo human hand, and ex vivo swine esophagus. Because speckle patterns can be generated over a large depth of field and field of view with simple coherent illumination, this approach may enable optical property mapping in new form-factors and applications, including endoscopy.
空间域成像可以在宽视场中绘制组织散射和吸收特性，因此在伤口评估和手术引导等临床应用中非常有用。该技术以前需要完全特征化的照明模式的投影。在这里，我们表明可以使用随机和未知的散斑照明来对已知空间频率下的组织调制传递函数进行采样，从而可以使用简单的激光二极管照明来对光特性进行定量映射。我们从每个像素的局部功率谱密度计算低和高空间频率响应参数，并使用查找表准确估计组织体模、体内人手和离体猪食管中的吸收和散射系数。由于可以使用简单的相干照明在大景深和视场中生成散斑图案，因此这种方法可能会使光学特性映射具有新的形式因素和应用，包括内窥镜检查。
