www.gusucode.com > 图像压缩编码码matlab实现 > 图像压缩编码码matlab实现/常用参数计算/entropy.m
function SHAN = entropy(x, n) % 计算熵,n是图像 x的灰度级,如果 n是默认则 n = 256 error(nargchk(1, 2, nargin)); if nargin<2 n = 256; end x = double(x); xh = hist(x(:), n); xh = xh/sum(xh(:)); i = find(xh); SHAN = -sum(xh(i).*log2(xh(i)));