def test_color_image_unsupported_error():
 img = np.zeros((20, 20, 3))
 keypoints = np.asarray([[7, 5], [11, 13]])
 assert_raises(ValueError, BRIEF().extract, img, keypoints)

def test_color_image_unsupported_error ( ) : img = np . zeros ( ( 20 , 20 , 3 ) ) keypoints = np . asarray ( [ [ 7 , 5 ] , [ 11 , 13 ] ] ) assert_raises ( ValueError , BRIEF ( ) . extract , img , keypoints )
brief descriptors can be evaluated on gray-scale images only .