Error 如下：
Linking...
: error LNK2001: unresolved external symbol _cvDestroyWindow
: error LNK2001: unresolved external symbol _cvLoadImage
: error LNK2001: unresolved external symbol _cvReleaseCapture
: error LNK2001: unresolved external symbol _cvReleaseImage
: error LNK2001: unresolved external symbol _cvWaitKey
: error LNK2001: unresolved external symbol _cvFlip
: error LNK2001: unresolved external symbol _cvCopy
: error LNK2001: unresolved external symbol _cvCreateImage
: error LNK2001: unresolved external symbol _cvRetrieveFrame
: error LNK2001: unresolved external symbol _cvGrabFrame
: error LNK2001: unresolved external symbol _cvNamedWindow
: error LNK2001: unresolved external symbol _cvCreateFileCapture
: error LNK2001: unresolved external symbol _cvCreateCameraCapture
: error LNK2001: unresolved external symbol _cvCreateMemStorage
: error LNK2001: unresolved external symbol _cvLoad
: error LNK2001: unresolved external symbol _cvShowImage
: error LNK2001: unresolved external symbol _cvCircle
: error LNK2001: unresolved external symbol _cvGetSeqElem
: error LNK2001: unresolved external symbol _cvGetTickFrequency
: error LNK2001: unresolved external symbol _cvHaarDetectObjects
: error LNK2001: unresolved external symbol _cvGetTickCount
: error LNK2001: unresolved external symbol _cvClearMemStorage
: error LNK2001: unresolved external symbol _cvEqualizeHist
: error LNK2001: unresolved external symbol _cvResize
: error LNK2001: unresolved external symbol _cvCvtColor
: fatal error LNK1120: 25 unresolved externals
Error executing link.exe.
- 26 error(s), 0 warning(s)
 
Solution如下： 
Menu：Project->Settings，选择右边的link标签，在Object/library modules附加上 cxcore.lib cv.lib ml.lib cvaux.lib highgui.lib cvcam.lib，然后确定，重新编译、链接即可！

From:http://blog.csdn.net/abcjennifer/article/details/7562719

OpenCv error ：unresolved external symbol（链接库没有加上）