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Proceedings Paper

Systolic array for computing the pixel purity index algorithm on hyperspectral images
Author(s): Dominique Lavenier; Erwan Fabiani; Steven Derrien; Charles Wagner
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Paper Abstract

The Pixel Purity Index (PPI) algorithm is used as a pre-processing to find end-members in a hyper spectral image. It tries to identify pure spectra by assigning a pixel purity index to each pixel in the image. The algorithm proceeds by generating a large number of random vectors through the hyper spectral image and by computing a dot-product between each vector and all the pixels. Since the number of random vectors is high (a few thousands), this algorithm may require hours of computation on standard computers. We present a systolic implementation of the PPI algorithm. It is based on a linear systolic array connected to a host processor through its external I/O bus system. In this scheme, the image is stored on the host processor memory and flushed several times through the array. The performance is mainly dictated by the I/O bus bandwidth and the ability to implement large systolic arrays: the fewer the passes needed through the array, the better the performance. The hardware implementation targets Xilinx Virtex boards, but the specification is independent of the platform: no external memories are required and the architecture works whatever the size of the linear systolic array. Experiments carried out on a low-cost reconfigurable board (a single Xilinx Virtex 800) show a speed-up of two orders of magnitude compared to a software implementation.

Paper Details

Date Published: 17 January 2002
PDF: 9 pages
Proc. SPIE 4480, Imaging Spectrometry VII, (17 January 2002); doi: 10.1117/12.453332
Show Author Affiliations
Dominique Lavenier, Institut de Recherche en Informatique et Systemes Aleatoires/CNRS (France)
Erwan Fabiani, Institut de Recherche en Informatique et Systemes Aleatoires/CNRS (France)
Steven Derrien, Institut de Recherche en Informatique et Systemes Aleatoires/CNRS (France)
Charles Wagner, Institut de Recherche en Informatique et Systemes Aleatoires/CNRS (France)


Published in SPIE Proceedings Vol. 4480:
Imaging Spectrometry VII
Michael R. Descour; Sylvia S. Shen, Editor(s)

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