我在C++ - Error中得到一个错误:不能将' cv::Point_ '转换为' cv: Point* {aka cv::Point_*} '作为回报

I'm try to run the code below and I'm getting an error. I'm creating an wrapper for an OpenCV function called 'Mat::at' and I'm trying to get it to compile to an '.so' on Ubuntu Trusty using 'G++'. I listed the contents of my '.cpp' file my '.hpp' file my error and my compile command below. I would appreciate any help on returning this C++ OpenCV function as a C pointer. Because that is my goal. Thank you.I'm try to run the code below and I'm getting a