Bug fix: camera image now converted to grayscale before tag detection
Bug fix: camera image now converted to grayscale before tag detection

The AprilTag reader apparently requires a grayscale image to correctly apply the detection algorithm to the full video stream. If color images are used, the reader only processes 1/3 of the image because it expects one channel instead of three.

BCLab-UNM/SwarmBaseCode-ROS,BCLab-UNM/SwarmBaseCode-ROS,BCLab-UNM/SwarmBaseCode-ROS,BCLab-UNM/SwarmBaseCode-ROS,BCLab-UNM/SwarmBaseCode-ROS,BCLab-UNM/SwarmBaseCode-ROS