🤖 AI Summary
This study addresses the challenges in hyperspectral unmixing posed by spectral variability, uncertainty in the number of endmembers, and the degradation of endmember distinctness as their count increases. To tackle these issues, the authors propose a hierarchical unmixing framework based on deep non-negative matrix factorization, incorporating hierarchical abundance constraints and a Binary Linear Unmixing with Tactile Hierarchies (BLUTHs) network architecture. A sparse modulation growth strategy is further integrated to adaptively construct scene-specific topologies, effectively revealing endmember structures across multi-scale spectral contrasts. Experimental results demonstrate that the proposed method outperforms state-of-the-art algorithms in abundance estimation within laboratory settings, remains competitive in remote sensing scenarios, and successfully applies to ocean color hyperspectral unmixing tasks using data from the HYPSO and PACE satellites.
📝 Abstract
Unmixing reveals the spatial distribution and spectral details of different constituents, called endmembers, in a hyperspectral image. Because unmixing has limited ground truth requirements, can accommodate mixed pixels, and is closely tied to light propagation, it is a uniquely powerful tool for analyzing hyperspectral images. However, spectral variability inhibits unmixing performance, the proper way to determine the number of endmembers is ambiguous, and the clarity of the endmembers degrades as more are included. Hierarchical structure is a possible solution to all three problems.
Here, hierarchical unmixing is defined by imposing a hierarchical abundance sum constraint on Deep Nonnegative Matrix Factorization. Binary Linear Unmixing Tactile Hierarchies (BLUTHs) solve the hierarchical unmixing problem with a simple network architecture. Sparsity modulation unmixing growth tailors the topology of a BLUTH to each scene. The structure imposed by BLUTHs allows endmembers with varying levels of spectral contrast to be revealed, mitigating the challenge of spectral variability.
The performance of BLUTHs exceeds state-of-the-art unmixing algorithms on laboratory scenes, particularly with regard to abundance estimation, while their performance remains competitive on remote sensing scenes. In addition, ocean color unmixing by BLUTHs is demonstrated on hyperspectral scenes from the HYPSO and PACE satellites.