Mosaicing of microscope images in the presence of large areas with insufficient information content

Abstract

In virtual microscopy, multiple overlapping fields of view are acquired from a large slide using a motorized microscope stage that moves and focuses the slide automatically. A virtual slide is reconstructed by combining digitally saved fields of view into an image mosaic. A seamless reconstruction requires the correction of unknown positioning errors of the stage. This is usually done by automatically estimating alignment parameters of the tiles in the image mosaic. But finding accurate alignment parameters can be inhibited by the presence of tiles that lack information content in the areas of overlap. In this work we propose a new mosaicing method that accesses information content of each overlap and performs pairwise registrations of adjacent tiles only if the content of their overlap is deemed sufficient for successful registration. For global positioning of tiles a stitching path is found by tracing such content-rich overlaps. We tested the proposed algorithm on bright field and fluorescence microscope images and compared the results with those of an existing algorithm based on simultaneous estimation of global alignment parameters. It is shown that the new algorithm improves perceived image quality at boundaries between tiles. Our method is also computationally efficient since it performs no more than one pairwise registration per tile on average.