ROS Developers LIVE Class #86: How to use OpenCV with ROS

hello there iam working with the above tutorial mentioned tutorial(ROS Developers LIVE Class #86: How to use OpenCV with ROS - YouTube). while using this command “rosrun linefollowing controller.py” i get soo many errors in the terminal.

and i can see that the drone is neither following the line nor moving. please suggest me to get through this error.
i have linked my rosject below.