Lines Matching defs:sigma
792 // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 )
794 // and sigma varies with radius.
795 // Based on some experimental radius values and sigma's
796 // we approximately fit sigma = f(radius) as
797 // sigma = radius * 0.3 + 0.6
799 // will resemble a box blur since with large sigma
801 float sigma = 0.3f * (float) radius + 0.6f;
807 float coeff1 = 1.0f / (sqrt( 2.0f * pi ) * sigma);
808 float coeff2 = - 1.0f / (2.0f * sigma * sigma);
