A DIVIDE-AND-CONQUER DICTIONARY LEARNING ALGORITHM AND ITS PERFORMANCE ANALYSIS

Mukherjee, Subhadip and Seelamantula, Chandra Sekhar (2016) A DIVIDE-AND-CONQUER DICTIONARY LEARNING ALGORITHM AND ITS PERFORMANCE ANALYSIS. In: IEEE International Conference on Acoustics, Speech, and Signal Processing, MAR 20-25, 2016, Shanghai, PEOPLES R CHINA, pp. 4712-4716.

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Abstract

We address the problem of learning a sparsifying synthesis dictionary over large datasets that occur in numerous signal and image processing applications, such as inpainting, super-resolution, etc. We develop a dictionary learning algorithm that exploits the similarity of the training examples to reduce the training time. Training datasets containing correlated examples typically occur in image processing applications, as the datasets contain the patches extracted from natural images as training vectors. Our algorithm employs a divide-and-conquer approach, where one leverages the correlation within the training examples to segment the dataset into clusters containing similar examples, and learn local dictionaries for each of them. This constitutes the divide step of the algorithm. In the conquer step, a global dictionary is trained using the atoms of the local dictionaries as the training examples. We analyze the run-time complexity and the representation error of the proposed divide-and-conquer dictionary learning algorithm, and compare the performance with the batch and online dictionary learning algorithms, both on synthesized dataset and natural images. The analysis reveals that the proposed algorithm has an asymptotic complexity that is linear and logarithmic in the number of training examples, corresponding to sequential and parallel implementations, respectively.

Item Type:	Conference Proceedings
Series.:	International Conference on Acoustics Speech and Signal Processing ICASSP
Additional Information:	Copy right for this article belongs to the IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA
Department/Centre:	Division of Electrical Sciences > Electrical Engineering
Date Deposited:	20 Jan 2017 04:27
Last Modified:	20 Jan 2017 04:27
URI:	http://eprints.iisc.ac.in/id/eprint/55935

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