OpenCV Error: Assertion failed ((scn == 3 || scn == 4) && (depth == CV_8U || depth == CV_32F)) - OpenCV Q&A Forum

Currently i am trying to track objects by color. I've run the documentation code, however, it gives the following sentences. The documentation code is here OpenCV Error: Assertion failed ((scn == 3 || scn == 4) && (depth == CV_8U || depth == CV_32F)) in cvtColor, file /home/guerrero/opencv2.4.9/opeā€¦