先安裝好opencv和 pkg-config.
看一下pkg-config設置的目錄是否正確, 假設opencv的目錄是/usr/loacal/include 和 /usr/local/lib:
$ pkg-config --cflags --libs opencv
-I/usr/local/include/opencv -I/usr/local/include -L/usr/local/lib -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core
linux下編譯命令：
g++ test.cpp -o test `pkg-config --cflags --libs opencv`