在學習高博士一起做RGBD-SLAM3時，遇到一些問題，現在記錄下來：

1、detectFeatures.cpp:37:16: error: ‘create’ is not a member of ‘cv::FeatureDetector {aka cv::Feature2D}’     detector = cv::FeatureDetector::create("ORB");

出現這個問題的主要原因是opencv版本不同，針對3.0以后的版本，特征提取器的聲明方式有變化：

detector = cv::ORB::create();具體的參數可以源碼查閱

2、detectFeatures.cpp.o：在函數‘main’中：detectFeatures.cpp:(.text+0xfb1)：對‘point2dTo3d(cv::Point3_<float>&, CAMERA_INTRINSIC_PARAMETERS&)’未定義的引用

在CmakeLists文件里面添加對slambase的依賴;

ADD_EXECUTABLE( detectFeatures detectFeatures.cpp )TARGET_LINK_LIBRARIES( detectFeatures slambase ${OpenCV_LIBS}     ${PCL_LIBRARIES} )

3、OpenCV Error: Assertion failed (confidence > 0 && confidence < 1) in run, file /home/limz/Cmake_module/opencv-3.2.0/modules/calib3d/src/ptsetreg.cpp, line 178terminate called after throwing an instance of 'cv::Exception'  what():  /home/limz/Cmake_module/opencv-3.2.0/modules/calib3d/src/ptsetreg.cpp:178: error: (-215) confidence > 0 && confidence < 1 in function run已放棄 (核心已轉儲)

同樣是由于opencv版本不同，而出現的問題，3.0以后對solvePnPRansac函數的定義進行類修正：

bool solvePnPRansac(InputArray _opoints, InputArray _ipoints,                        InputArray _cameraMatrix, InputArray _distCoeffs,                        OutputArray _rvec, OutputArray _tvec, bool useExtrinsicGuess,                        int iterationsCount, float reprojectionError, double confidence,                        OutputArray _inliers, int flags)

增加了confidence：算法產生有用結果的置信系數

具體函數的學習可以參考這篇博客： 

opencv中solvePnPRansac函數求解相機位姿