A Method to Mitigate Refractive Index Mismatch Artefacts for Scanning Laser Optical Tomography

SLOT is a volumetric, multi-modal imaging technique. Point-wise illumination with a weakly focused laser beam results in projection images that are reconstructed into tomographic images. The sample is embedded in a refractive index (RI) matched medium, which prevents light refraction at the sample boundary, which would lead to image artifacts. Silicone oil is used as the immersion medium for SLOT. It is toxic, difficult to remove from samples and can interact with the sample in undesirable ways. Using water as an immersion medium would solve these problems. Unfortunately, the refraction between water and the sample leads to artifacts that drastically degrade the quality of the results. This work aims to eliminate the artifacts through a clever post processing of the sinogram by predicting the refraction of each laser beam. The SLOT simulator was programmed for this purpose. It allows the simulation of SLOT measurements with any RI's and the correction of SLOT measurements with an RI mismatch. Simulated and real SLOT measurements are presented and their similarity is evaluated.