def prepare_velo_points(pts3d_raw):
	"""
	Replaces the reflectance value by 1, and tranposes the array, so
	points can be directly multiplied by the camera projection matrix
	"""

	pts3d = pts3d_raw
	# Reflectance > 0
	pts3d = pts3d[pts3d[:, 3] > 0 ,:]
	pts3d[:,3] = 1
	return pts3d.transpose()