US 7,321,691 B1
Method for selecting representative endmember components from spectral data
Jessica Miriam Sunshine, Potomac, Md. (US); Stefanie Tompkins, Centreville, Va. (US); and Kellie Sue McNaron-Brown, Centreville, Va. (US)
Assigned to Science Applications International Corporation, San Diego, Calif. (US)
Filed on Apr. 11, 2007, as Appl. No. 11/783,692.
Application 11/783692 is a continuation of application No. 11/333360, filed on Jan. 18, 2006, granted, now 7,221,798.
Application 11/333360 is a continuation of application No. 10/821928, filed on Apr. 12, 2004, granted, now 7,085,416.
Application 10/821928 is a continuation of application No. 10/387867, filed on Mar. 14, 2003, granted, now 6,741,740.
Application 10/387867 is a continuation of application No. 09/901680, filed on Jul. 11, 2001, granted, now 6,608,931.
Int. Cl. G06K 9/46 (2006.01); G06K 9/62 (2006.01); G06K 9/40 (2006.01)
U.S. Cl. 382—191  [382/225; 382/274] 9 Claims
OG exemplary drawing
 
1. A computer readable medium encoded with a computer program for aiding a user in the selection of a candidate spectral endmember for a scene composed of multiple pixels comprising:
receiving scene reflectance data comprised of multiple unknown spectra;
receiving reference spectral data comprised of multiple known spectra;
comparing each unknown spectra to the known spectra, each being represented as a vector in n-dimension space, by measuring the angle of separation between the each unknown spectra vector and each known spectra vector;
selecting unknown spectra with smallest measured angles of vector separation from known spectra as candidate spectral endmembers;
unmixing each of the multiple pixels to determine percentage contribution of each of the candidate spectral endmembers to each of the multiple pixels;
applying a shade mask to the unmixed pixels, resulting in X number of pixels which have less than a threshold amount of shade determined by the shade mask;
generating a root mean square (RMS) error image utilizing the X number of pixels;
setting an RMS minimum and maximum range, wherein pixels falling with the range represent candidate spectral endmembers; and
comparing the X number of pixels to the range to determine candidate spectral endmembers; and
selecting a candidate spectral endmember.