On the Estimation of Extrinsic and Intrinsic Parameters of Optical Microscope Calibration

Abstract

This paper compares several camera calibration methods on the estimation of specific extrinsic and intrinsic parameters. Good estimates of the chosen parameters, rotation and radial lens distortion are essential to increase the accuracy of quantitative measurements and to accurately stitch single field of view-based images together. The parameters are obtained using two selected methods on different objective magnifications on a microscope system using a fixed grid calibration pattern. We evaluate two methods and show that the rotation angles from one of the methods is consistent with a simple homography while the other estimates a consistently smaller angle. The radial distortion estimates are both very small and relate to a distortion of less than one pixel.

Methods for rapid and high quality acquisition of whole slide images

“…Some methods use one or multiple of the above methods, and others extend the stitching to 3D (aligning images at multiple focal planes simultaneously) (Nozaka et al 2013;Preibisch et al 2009). Prior to the stitch, any intrinsic (geometric distortion) and extrinsic dis-tortions (rotation of the camera) in the raw images should be corrected in order to effectively match the individual images (Altinay et al 2010;Sun et al 2005). Geometric removals are also essential for quantitive evaluation.…”