A radial distortion compensation method for artifact-free multi-adjacent-tile stitching/mosaicking in Mesoscopic Optical Microscopy

Abstract

Mesoscopic optical imaging of an ultra-large biological sample demands a large enough field of view (FOV) in order to reduce the requirement of extensive digital image stitching operations. For an objective lens with a specific magnification, when we continue extending the FOV, the adverse effects of optical aberrations become prominent. One of such effects is radial distortion towards the edges and corners of a square-shaped FOV. Consequently, when we attempt to mosaic/stitch multiple of such radially distorted adjacent tiles, it often becomes challenging to avoid artifacts or discontinuity of structures especially at the joining of such adjacent tiles. To address the same, we apply a preestimated opposite radial distortion to each acquired tile prior to applying an alignment algorithm. Employing a bruteforced approach, we one-time quantify a suitable compensating radial distortion. We apply this method in a custom-built large-FOV nonlinear optical microscope (NLOM) system and demonstrate an artifact-free mosaic-stitching operation.