Fresnel diffraction as a means of detection of optical discontinuities in turbid media of biological significance

Summary form only given. The authors report the results of a series of measurements that were taken on one-dimensional and two-dimensional objects that are hidden in highly scattering media. Diffraction patterns were recognized through their dependence on the distance between object and detector. Early-arriving photons-based profiles of the discontinuities were fitted by Fresnel theory patterns and resulted images were corrected using the corresponding object size, which was responsible for the best fitting pattern. It is concluded that the method described in this study may have a significant impact on biomedical applications where opaque or almost opaque material are imaged through turbid media. It is expected that microscopic measurements of small structures such as erythrocytes (ektacytometry) may be possible even when the cells are surrounded by an optically thick medium.