Adding only 90 degrees rotations to augmentations

[ivankovd]

Hi! I wonder what exactly should I pass to 'degrees' param in hyp.scratch.yaml in order to add only [0, 90, 180, 270] degrees rotations to augmentations during network training? I've found several same or related questions in issues but no direct answers were provided.
As I understood from the documentation, 'degrees' param could be 0 or +-180 (btw does the sign mean that if I will put here '+180' - only clockwise rotations will be applied and if '-180' - only counterclockwise?), so what should I do if I want both clock and counterclockwise rotations range?
Also, I found commented out line of code in random_perspective function in https://github.com/ultralytics/yolov5/blob/master/utils/augmentations.py which looks like what I need, but I suppose there should be more simple way to make it using the hyperparameters config mentioned earlier.
Thanks anybody in advance for help!

[glenn-jocher]

@ivankovd you can simply uncomment L145 here to allow discrete random 90deg rotations:

yolov5/utils/augmentations.py

Lines 142 to 149 in c1249a4

	# Rotation and Scale
	R = np.eye(3)
	a = random.uniform(-degrees, degrees)
	# a += random.choice([-180, -90, 0, 90]) # add 90deg rotations to small rotations
	s = random.uniform(1 - scale, 1 + scale)
	# s = 2 ** random.uniform(-scale, scale)
	R[:2] = cv2.getRotationMatrix2D(angle=a, center=(0, 0), scale=s)