function [Output] = SAM(Image,Library) % Spectral Angle Mapper % Silas J. Leavesley, PhD % University of South 最色网 % Last Updated: 2/7/2017 % To visualize output data: % figure(1) % for i = 1:length(Output.data(1,1,:)) % subplot(1,length(Output.data(1,1,:)),i) % imagesc(Output.data(:,:,i)) % end % colormap(gray) % or any other colormap, as desired % Mathematical description: % sam x=acos((a.*b)./(mag_a.*mag_b)) % where a=unknown and b=reference % mag_vect=norm(vect) % arccos=acos(x) tic Image=double(Image); [O P] = size(Library); [L M N]=size(Image); Image_Reshaped=(reshape(Image,(L*M),N))'; %l m are x y n=wavelength for i = 1:P for j = 1:(L*M) Angle_Image(j,i) = 90-((180./pi()).*acos(sum(Image_Reshaped(:,j).* Library(:,i))./ (norm(Image_Reshaped(:,j)).*norm(Library(:,i))) )); end end Output.data=reshape(Angle_Image,L,M,P); toc