Hyperspectral image coding using graph wavelets
Hyperspectral imaging captures the spectral responses of different wavelengths per pixel for an entire image. Because the number of spectral bands is large, efficient compression of hyperspectral images is important. Leveraging on recent advances in graph signal processing (GSP), in this paper we propose to encode a hyperspectral image in groups of ω spectral bands using graph wavelets, exploiting correlations along both the spatial and the spectral dimensions. Specifically, along the spatial dimension, we estimate the inter-pixel correlations for all adjacent pixel pairs from the last image in the previous coded band group. Along the spectral dimension, we first divide an image into different spatial regions with similar spectral responses, and encode the spectral signature (correlations along the spectrum) for each region as side information (SI). The spatial / spectral correlations are used to compute edge weights to construct a graph for signal-adaptive graph wavelet based compression. Experimental results suggest that our proposal can outperform existing schemes noticeably at comparable complexity.