Superpixel-Based and Spatially Regularized Diffusion Learning for Unsupervised Hyperspectral Image Clustering

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

7 Scopus Citations
View graph of relations

Author(s)

  • Sam L. Polk
  • Yinyi Lin
  • Hongsheng Zhang
  • James M. Murphy
  • Robert J. Plemmons

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number4405818
Journal / PublicationIEEE Transactions on Geoscience and Remote Sensing
Volume62
Online published4 Apr 2024
Publication statusPublished - 2024

Abstract

Hyperspectral images (HSIs) provide exceptional spatial and spectral resolution of a scene, crucial for various remote sensing applications. However, the high dimensionality, presence of noise and outliers, and the need for precise labels of HSIs present significant challenges to the analysis of HSIs, motivating the development of performant HSI clustering algorithms. This article introduces a novel unsupervised HSI clustering algorithm—superpixel-based and spatially regularized diffusion learning (S2DL)—which addresses these challenges by incorporating rich spatial information encoded in HSIs into diffusion geometry-based clustering. S2DL employs the entropy rate superpixel (ERS) segmentation technique to partition an image into superpixels, then constructs a spatially regularized diffusion graph using the most representative high-density pixels. This approach reduces computational burden while preserving accuracy. Cluster modes, serving as exemplars for underlying cluster structure, are identified as the highest-density pixels farthest in diffusion distance from other highest-density pixels. These modes guide the labeling of the remaining representative pixels from ERS superpixels. Finally, majority voting is applied to the labels assigned within each superpixel to propagate labels to the rest of the image. This spatial–spectral approach simultaneously simplifies graph construction, reduces computational cost, and improves clustering performance. S2DL’s performance is illustrated with extensive experiments on four publicly available, real-world HSIs: Indian Pines, Salinas, Salinas A, and WHU-Hi. Additionally, we apply S2DL to landscape-scale, unsupervised mangrove species mapping in the Mai Po Nature Reserve (MPNR), Hong Kong, using a Gaofen-5 HSI. The success of S2DL in these diverse numerical experiments indicates its efficacy on a wide range of important unsupervised remote sensing analysis tasks. © 2024 IEEE.

Research Area(s)

  • Diffusion geometry, hyperspectral image (HSI) clustering, spatial regularization, species mapping, superpixel segmentation

Citation Format(s)

Superpixel-Based and Spatially Regularized Diffusion Learning for Unsupervised Hyperspectral Image Clustering. / Cui, Kangning; Li, Ruoning; Polk, Sam L. et al.
In: IEEE Transactions on Geoscience and Remote Sensing, Vol. 62, 4405818, 2024.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review