Using Blocks of Skewers for Faster Computation of Pixel Purity Index.

Theiler, J. ; Lavenier, D. D. ; Harvey, N. R. ; Perkins, S. J. ; Szymanski, J. J.

Technical Information Center Oak Ridge Tennessee

关键词: Remote sensing;    Pixels;    Purity;    Algorithms;    Vectors(Mathematics);   

RP-ID  :  PB2001105678

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The pixel purity index (PPI) algorithm proposed by Boardman, et al identifies potential endmember pixels in multispectral imagery. The algorithm generates a large number of skewers (unit vectors in random directions), and then computes the dot product of each skewer with each pixel. We report on a variant of the PPI algorithm in which blocks of B skewers are considered at a time. From the computation of B dot products, one can produce a much larger set of derived dot products that are associated with skewers that are linear combinations of the original B skewers. Since the derived dot products involve only scalar operations, instead of full vector dot products, they can be very cheaply computed.