A Clustering Approach to Optimize Online Dictionary Learning


Dictionary learning has emerged as a powerful tool for low level image processing tasks such as denoising and in-painting, as well as sparse coding and representation of images. While there has been extensive work on the development of online and offline dictionary learning algorithms to perform the aforementioned tasks, the problem of choosing an appropriate dictionary size is not as widely addressed. In this paper, we introduce a new scheme to reduce and optimize dictionary size in an online setting by synthesizing new atoms from multiple previous ones. We show that this method performs as well as existing offline and online dictionary learning algorithms in terms of representation accuracy while achieving significant speedup in dictionary reconstruction and image encoding times. Our method not only helps in choosing smaller and more representative dictionaries, but also enables learning of more incoherent ones.


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    •  NEWS    ICASSP 2012: 8 publications by Petros T. Boufounos, Dehong Liu, John R. Hershey, Jonathan Le Roux and Zafer Sahinoglu
      Date: March 25, 2012
      Where: IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
      MERL Contacts: Dehong Liu; Jonathan Le Roux; Petros T. Boufounos
      • The papers "Dictionary Learning Based Pan-Sharpening" by Liu, D. and Boufounos, P.T., "Multiple Dictionary Learning for Blocking Artifacts Reduction" by Wang, Y. and Porikli, F., "A Compressive Phase-Locked Loop" by Schnelle, S.R., Slavinsky, J.P., Boufounos, P.T., Davenport, M.A. and Baraniuk, R.G., "Indirect Model-based Speech Enhancement" by Le Roux, J. and Hershey, J.R., "A Clustering Approach to Optimize Online Dictionary Learning" by Rao, N. and Porikli, F., "Parametric Multichannel Adaptive Signal Detection: Exploiting Persymmetric Structure" by Wang, P., Sahinoglu, Z., Pun, M.-O. and Li, H., "Additive Noise Removal by Sparse Reconstruction on Image Affinity Nets" by Sundaresan, R. and Porikli, F. and "Depth Sensing Using Active Coherent Illumination" by Boufounos, P.T. were presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP).