unresolved external symbol error when importing libraries for OpenCV2.3 in Visual Studios 2010 Express C++

first time posting a question here to stackoverflow. Sorry if I butcher the formatting!

I am attempting to follow a basic tutorial on openCV, namely this one: http://aishack.in/tutorials/tracking-colored-objects-in-opencv/

I have looked at various tutorial online on how to install openCV, including:

Setup OpenCV-2.3 for Visual Studio 2010 and opencv.willowgarage.com/wiki/VisualC%2B%2B

without much luck.

The current version I have running right now is OpenCV 2.3.0. I am currently running on Windows 7 with Microsoft Visual C++ Express 2010.

Whenever I try to build and run my code, I get the following errors:

1>------ Build started: Project: Camera, Configuration: Debug Win32 ------
1>camera.obj : error LNK2019: unresolved external symbol _cvReleaseImage referenced in function "struct _IplImage * __cdecl GetThresholdedImage(struct _IplImage *)" (?GetThresholdedImage@@YAPAU_IplImage@@PAU1@@Z)
1>camera.obj : error LNK2019: unresolved external symbol _cvInRangeS referenced in function "struct _IplImage * __cdecl GetThresholdedImage(struct _IplImage *)" (?GetThresholdedImage@@YAPAU_IplImage@@PAU1@@Z)
1>camera.obj : error LNK2019: unresolved external symbol _cvCvtColor referenced in function "struct _IplImage * __cdecl GetThresholdedImage(struct _IplImage *)" (?GetThresholdedImage@@YAPAU_IplImage@@PAU1@@Z)
1>camera.obj : error LNK2019: unresolved external symbol _cvCreateImage referenced in function "struct _IplImage * __cdecl GetThresholdedImage(struct _IplImage *)" (?GetThresholdedImage@@YAPAU_IplImage@@PAU1@@Z)
1>camera.obj : error LNK2019: unresolved external symbol _cvGetSize referenced in function "struct _IplImage * __cdecl GetThresholdedImage(struct _IplImage *)" (?GetThresholdedImage@@YA


                    
                    
                        
                        visual-studio-2010
                        
                        opencv
                        
                        lnk2019
                        
                    
                    
                        
                        
                        
                        
                        
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I had a similar problem while I was trying to compile cvblob library (http://code.google.com/p/cvblob/) on Windows 7 32bit with Visual Studio 2010.

If everything else is done properly try my guess written below. If not start with these tutorials:

Installing OpenCV: http://docs.opencv.org/trunk/doc/tutorials/introduction/windows_install/windows_install.html#cpptutwindowsmakeown
Configuring your projects to build and work with opencv: http://docs.opencv.org/trunk/doc/tutorials/introduction/windows_visual_studio_Opencv/windows_visual_studio_Opencv.html#windows-visual-studio-how-to.

These silimar linker errors disappeared after changing some project properties:
- In VS 2010 open Your solution
- Open solution explorer (View->Solution Explorer)
- Find a project that generated these linker errors. (In my example it was a project called "cvblob" inside solution called "cvBlob" generated by cmake.)
- right click on that project
- From the context menu select properties
- On the left select Configuration properties -> General and find a field called "Target extension"
- In Project Details find your project settings for "Configuration Type"
- analyse them. In my particular problem of compiling cvblob I had to set Target extension to .lib and Configuration type to Static library. This is also a solution for guys trying to compile cvblob library in Visual Studio 2010

answered 2012-05-19T15:25:02.077

unresolved external symbol error when importing libraries for OpenCV2.3 in Visual Studios 2010 Express C++

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