Strange results when using on non grayscale images

[rafis]

Your keypoint detection algorithm is very similar to OpenCV's SIFT. But descriptors extraction gives strange results when used on non grayscale images, for example Hue (from HSV), Saturation (from HSV), Cr (from YCrCb), Cb (from YCrCb). Have you tested descriptors after moving from Python 2 to Python 3?