To the Graduate Council: I am submitting herewith a thesis written by ...

Chapter 2: Literature Review 72 LITERATURE REVIEWIn this chapter we present a review of the research literature. In Section 2.1 weintroduce the reader to shape and its implication to computer vision and briefly reviewsome key methods on 2D images in Section 2.2. We discuss contemporary research in3D computer vision for shape analysis in Section 2.3 and summarize our survey inSection 2.4.2.1 Cognition and Computer VisionThe human cognitive system is designed to interpret sensory data with suchremarkable speed and accuracy that we fail to appreciate millions of computationsinvolved in a common event of identifying an object. An impressive component inhuman perception is our ability to recognize 3D objects from their 2D retinalprojections. Stankiewicz outlines human visual perception into three possiblehypotheses, namely the feature model approach, alignment model approach and thepart-based approach [Stankiewicz, 2002]. Feature models propose that the visualsystem does not match a precise numerical array of an object with another butremembers a collection of features in memory. According to this approach the locationof the features in a particular image is less significant than its presence in the image.The feature model approach fails with increasing occlusions and is less reliable whenthe spatial relationship between the features and the image are vital in recognizing theobject. Alignment models make use of the spatial information to compensate forviewpoint changes but do not consider occlusions. They can handle Euclideantransformations such as the rotation, translation and scaling and are accepted to berobust in comparison with the feature models. Part-based models operate bydecomposing an object into its constituent parts. The approach uses image features todescribe the shape of parts in addition to documenting relationships between parts.The part-based model has not met with great success in computer vision because ofthe insufficiency in intensity images to segment objects as parts, but with theincreasing computational capabilities and improvements in sensor technology towards3D imaging, part-based models are a good prospect.