function y = imthrsh(x, xa, xb, ya, yb) % Image Thresholding L = 256; if nargin == 1, xa = 3*L/8-1; xb = 5*L/8-1; ya = L/8-1; yb = 7*L/8-1; elseif nargin < 5 return end y = zeros(size(x)); x = double(x); % I k = x<=xa; y(k) = ya; % II k = (x>xa)&(x<=xb); y(k) = yb; % III k = (x>xb); y(k) = ya;