Image denoising: Threshold calculation for oraclesoft

This function used to calculate the threshold for oracleshrink image denoising method

function thr = oracleshrink1(CD,T)
%function used to calculate threshold for oracleshrink method
CD = CD(:)';
n = length(CD);
sx2 = (T-CD).^2;
b  = cumsum(sx2);
[risk,best] = min(b);
hr = sqrt(sx2(best));