Hello,
I just changed my software which was using opencv 2.4.9 version to opencv 3.1.0 and I am having a very very little differences from cv::mean function.
cv::Scalar aux1 = cv::mean(img_32);
std::cout << "MEAN: "<< aux1.val[0] << std::endl;
Output with opencv 2.4.9:
From ORIGINAL [img_32]: [169,168,208] // Some pixel values from img_32
MEAN: 0.439712
Output with opencv 3.1.0:
From UPDATED [img_32]: [169,168,208] // Some pixel values from img_32
MEAN: 0.439713
I checked rigorously if there were differences in the image....