Browsing All Posts published on »July, 2011«

SparsePCA in scikits.learn-git

July 19, 2011

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I am happy to announce that the Sparse PCA code has been reviewed and merged into the main scikits.learn repository. You can use it if you install the bleeding edge scikits.learn git version, by first downloading the source code as explained in the user’s guide, and then running python setup.py install. To see what code […]

K-Means for dictionary learning

July 10, 2011

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One of the simplest, and yet most heavily constrained form of matrix factorization, is vector quantization (VQ). Heavily used in image/video compression, the VQ problem is a factorization where (our dictionary) is called the codebook and is designed to cover the cloud of data points effectively, and each line of is a unit vector. This […]

Image denoising with dictionary learning

July 7, 2011

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I am presenting an image denoising example that fully runs under my local scikits-learn fork. Coming soon near you! The 400 square pixels area covering Lena’s face was distorted by additive gaussian noise with a standard deviation of 50 (pixel values are ranged 0-256.) The dictionary contains 100 atoms of shape 4×4 and was trained […]