The recognition of pollen grains is a challenging task since they are three-dimensional structures with complex morphological characteristics. Palynologists are responsible for studying pollen, spores and similar microscopic plant structures. In this work, we develop and analyze an automatic method for classification of pollen grain images based on a set of features and classifiers. Predictions of different classifiers are fused into an ensemble rule of majority voting. Experiments conducted on two datasets containing different types of pollen grains are used to demonstrate the effectiveness of the proposed approach.

Classification of Pollen Grain Images Based on an Ensemble of Classifiers

In this work we present a new approach to the extraction of features robust to focal mismatches, for the classification of biological particles characterized by 3 dimensional structures. We use SIFT descriptors in order to encode local gradient, fused with features derived from an introduced adaptive filterbank of Gabor filters. We have evaluated the proposed technique using a dataset consisting of 174 images of pollen grains from 29 species, acquired with a low-cost optical microscope in arbitrary focal planes. The proposed descriptor efficiently captures discriminative information by encoding the local inner and outer structure of the transparent pollens in a focus-tolerant manner, achieving approximately 74.5% classification accuracy, demonstrating that local scale invariant features can be robust even under challenging conditions.

Nefeli Vassiliki Politi-Stergiou

Papers

Local focus-tolerant image descriptors for classification of biological particles