Lateral resolution improvement in Optical Coherence Tomography (OCT) images

A novel method for lateral resolution improvement of Optical Coherence Tomography (OCT) images, which is independent of the focusing of the delivery optics and the depth of field, is presented. This method was inspired by radar range oversampling techniques. It is based on the lateral oversampling of the image and the estimation of the locations of the multiple scatterers which contribute to the signal. The information in the oversampled images is used to estimate the locations of multiple scatterers assuming each contributes a weighted portion to the detected signal, the weight determined by the location of the scatterer and the point spread function (PSF) of the system. A priori knowledge of the PSF is not required since optimization techniques can be employed to achieve the best possible enhancement of the image resolution. Preliminary results of such an approach on laterally oversampled OCT images have shown that it is possible to achieve a two-fold lateral resolution improvement. Moreover by performing deconvolution with the new improved PSF the lateral resolution can be further improved by another factor of two for a total of 4x improvement. Such improvement can be significant, especially in cases where the Numerical Aperture (NA) of the delivery optics is limited, such as, for example, in the case of ophthalmic imaging where the optics of the eye itself limit the lateral resolution.