Estimation of Weighted Multi-Scatterer Contributions for Improvement of Lateral Resolution of Optical Coherence Tomography Images

A method for improvement of lateral resolution in Optical Coherence Tomography (OCT) is presented. The resolution improvement achieved with this method does not depend on the delivery optics. Moreover the depth of focus is not restricted. The method is based on the lateral oversampling of the image. The laterally oversampled signals are backscattered signals from shifted and overlapped resolution volumes. Signals from successive volumes are correlated due to the region shared by adjacent resolution volumes. By utilizing the cross correlation of signals from such overlapped volumes, resolution can be improved by various degrees depending on which pairs of signals are used. To maximize the resolution improvement for a given oversampling factor, signals from the farthest spaced and overlapped resolution volumes should be processed. The cost of the resolution refinement is the increasing statistical error because the magnitude of the cross-correlation function becomes smaller. In this method signals from all overlapped volumes are combined optimally to improve the resolution using all the available cross correlations. Preliminary results of such an approach on laterally oversampled OCT images have shown that it is possible to achieve a 3.7-fold lateral resolution improvement.