Lines Matching refs:sigma
39 // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 )
41 // and sigma varies with radius.
42 // Based on some experimental radius values and sigma's
43 // we approximately fit sigma = f(radius) as
44 // sigma = radius * 0.4 + 0.6
46 // will resemble a box blur since with large sigma
48 float sigma = 0.4f * (float)radius + 0.6f;
54 float coeff1 = 1.0f / (sqrt( 2.0f * pi ) * sigma);
55 float coeff2 = - 1.0f / (2.0f * sigma * sigma);