How does cv::normalize work for multi channel images?

When i have a multi-channel image as cv::Mat and i run a min-max normalization like that:

    cv::Mat normalizedImage = cv::Mat::zeros(imageToNormalize.size(), CV_32F);
    cv::normalize(imageToNormalize, normalizedImage, -1.0, 1.0, cv::NORM_MINMAX);

Is every channel of the image normalized independently, or are the min-max values gathered from all channels and applied to all accordingly?