(-215:Assertion failed) count >= 0 && (depth == CV_32F || depth == CV_32S) in function 'cv::arcLength'什么意思

This error message is caused by an assertion failure, which means that the program has encountered a situation that it was not designed to handle. Specifically, the error message "(-215:Assertion failed) count >= 0" indicates that the program has encountered a negative value for a variable called "count", which is not allowed in the context of the program.

To fix this error, you will need to identify the source of the negative value and modify the program to prevent it from occurring. This may involve adding additional error checking or modifying the logic of the program to handle negative values appropriately.