  In this article, we propose an automatic method for the segmentation of
pollen grains from microscope images, followed by the automatic segmentation of
their exine. The objective of exine segmentation is to separate the pollen
grain in two regions of interest: exine and inner part. A coarse-to-fine
approach ensures a smooth and accurate segmentation of both structures. As a
rough stage, grain segmentation is performed by a procedure involving
clustering and morphological operations, while the exine is approximated by an
iterative procedure consisting in consecutive cropping steps of the pollen
grain. A snake-based segmentation is performed to refine the segmentation of
both structures. Results have shown that our segmentation method is able to
deal with different pollen types, as well as with different types of exine and
inner part appearance. The proposed segmentation method aims to be generic and
has been designed as one of the core steps of an automatic pollen
classification framework.
