Learning Parts-Based Representations of Data
David A. Ross, Richard S. Zemel; 7(84):2369−2397, 2006.
Many perceptual models and theories hinge on treating objects as a collection of constituent parts. When applying these approaches to data, a fundamental problem arises: how can we determine what are the parts? We attack this problem using learning, proposing a form of generative latent factor model, in which each data dimension is allowed to select a different factor or part as its explanation. This approach permits a range of variations that posit different models for the appearance of a part. Here we provide the details for two such models: a discrete and a continuous one. Further, we show that this latent factor model can be extended hierarchically to account for correlations between the appearances of different parts. This permits modelling of data consisting of multiple categories, and learning these categories simultaneously with the parts when they are unobserved. Experiments demonstrate the ability to learn parts-based representations, and categories, of facial images and user-preference data.
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