function sgray(alpha)%SGRAY: Non-linear transformation of a color gray colormap.%  Same effect as clipping.%%  sgray(alpha)%%  IN:   alpha: degree of clustering of B&W (try 5)%%%  Author(s): M.D.Sacchi (sacchi@phys.ualberta.ca)%  Copyright 1998-2003 SeismicLab%  Revision: 1.2  Date: Dec/2002 %  %  Signal Analysis and Imaging Group (SAIG)%  Department of Physics, UofA%i0=32;i = 1:64;t = (atan((i-i0)/alpha))';s = t(64);t = (t - min(t))*1./(max(t) -min(t));m(1:64,2) = 1-t;m(:,1) = 1-t;m(:,3) =1-t;colormap(m);