6533b7d9fe1ef96bd126d2ff

RESEARCH PRODUCT

Image-based detection and classification of allergenic pollen

Gildardo Lozano Vega

subject

Reconnaissance de formesSélection de caractéristiquesObject extractionClassificationPalynologyExtraction d’objetsAperturesPalynologiePattern recognitionFeature selectionFeature extractionBag of wordsExtraction de caractéristiquesSac-de-mots[SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing

description

The correct classification of airborne pollen is relevant for medical treatment of allergies, and the regular manual process is costly and time consuming. An automatic processing would increase considerably the potential of pollen counting. Modern computer vision techniques enable the detection of discriminant pollen characteristics. In this thesis, a set of relevant image-based features for the recognition of top allergenic pollen taxa is proposed and analyzed. The foundation of our proposal is the evaluation of groups of features that can properly describe pollen in terms of shape, texture, size and apertures. The features are extracted on typical brightfield microscope images that enable the easy reproducibility of the method. A process of feature selection is applied to each group for the determination of relevance.Regarding apertures, a flexible method for detection, localization and counting of apertures of different pollen taxa with varying appearances is proposed. Aperture description is based on primitive images following the Bag-of-Words strategy. A confidence map is built from the classification confidence of sampled regions. From this map, aperture features are extracted, which include the count of apertures. The method is designed to be extended modularly to new aperture types employing the same algorithm to build individual classifiers.The feature groups are tested individually and jointly on of the most allergenic pollen taxa in Germany. They demonstrated to overcome the intra-class variance and inter-class similarity in a SVM classification scheme. The global joint test led to accuracy of 98.2%, comparable to the state-of-the-art procedures.

https://theses.hal.science/tel-01253119