Text

theses

Visual object recognition is a challenging problem with a wide range of real-life applications. The difficulty of this problem is due to variation in shape and appearance among objects within the same category, as well as varying viewing conditions, such as viewpoint, scale, illumination, occlusion and articulation of multi-part deformable objects. In addition, beyond the visual spectrum, depth and range sensors suffer from noise that inhibits object recognition. Under visual object recognition lie three subproblems that are each challenging: category recognition, instance recognition and pose estimation. Impressive work has been done in the last decade on developing systems for generic object recognition. Previous research has covered many recognition-related issues, however, the problem of multi-view recognition remains among the most fundamental challenges in computer vision. In this dissertation we focus on discovering low-dimensional latent representations that enable efficient joint multi-view object recognition over multiple modalities. These discovered latent representations allow us to work in lower dimensional latent spaces that capture the factors needed for object recognition from multi-view images and over multiple modalities; from images to depthmaps and 3D point clouds. Each of the models we present in this dissertation explore a different representation space of latent factors. The first model builds multiple kernel induced spaces to fuse information between different modalities and performs object pose estimation in a regression framework. The second model performs manifold analysis to solve categorization and pose estimation simultaneously. It does this by factorizing the space of topological mappings between a unified conceptual manifold and feature spaces. We present two variations of this; an unsupervised learning model and a supervised learning model. The third approach analyzes the representational spaces of the layers of Convolutional Neural Networks and builds on the findings by proposing a network that jointly solves category and pose. The fourth approach explores solving pose-invariant categorization of multi-part objects by shape information, in the form of 3D point clouds. We build a representation that inherently encodes pose and allows objects to be represented by multiple levels of object-part decompositions for more robust object recognition. In each approach we support our hypotheses by extensive experimentation.

ETD_6938

Ph.D.

Includes bibliographical references

by Tarek El-Gaaly

doi:10.7282/T3ZG6V98

ETD doctoral

The author owns the copyright to this work.