Simultaneous Grouping and Denoising via Sparse Convex Wavelet Clustering
This work provides a unified, convex approach for simultaneously denoising and clustering noisy signals, which could benefit data scientists and signal processors working with noisy data.
This paper introduces a sparse convex wavelet clustering method that simultaneously denoises and groups noisy signals. It achieves this by combining convex fusion penalties for agglomeration and group-sparse penalties for wavelet-domain denoising, resulting in denoised and wavelet-sparse cluster centroids.
Clustering is a ubiquitous problem in data science and signal processing. In many applications where we observe noisy signals, it is common practice to first denoise the data, perhaps using wavelet denoising, and then to apply a clustering algorithm. In this paper, we develop a sparse convex wavelet clustering approach that simultaneously denoises and discovers groups. Our approach utilizes convex fusion penalties to achieve agglomeration and group-sparse penalties to denoise through sparsity in the wavelet domain. In contrast to common practice which denoises then clusters, our method is a unified, convex approach that performs both simultaneously. Our method yields denoised (wavelet-sparse) cluster centroids that both improve interpretability and data compression. We demonstrate our method on synthetic examples and in an application to NMR spectroscopy.