OpenCV - DLL missing, but it's not?

Question

I am trying just a basic program with OpenCV with the following code:

#include "cv.h"
#include "highgui.h"

int main()
{
    IplImage* newImg;
    newImg = cvLoadImage("~/apple.bmp", 1);
    cvNamedWindow("Window", 1);
    cvShowImage("Window", newImg);
    cvWaitKey(0);
    cvDestroyWindow("Window");
    cvReleaseImage(&newImg);
    return 0;
}

When I run this, I get

The program can't start because libcxcore200.dll is missing from your computer. Try reinstalling the program to fix this problem.

However, I can see this DLL. It exists. I have added the following to the input dependencies for my linker

C:\OpenCV2.0\lib\libcv200.dll.a C:\OpenCV2.0\lib\libcvaux200.dll.a C:\OpenCV2.0\lib\libcxcore200.dll.a C:\OpenCV2.0\lib\libhighgui200.dll.a

What gives? I'm using visual studio 2008.

When I link the .dll files instead of .dll.a files, I get

fatal error LNK1107:invalid or corrupt file: cannot read at 0x3F8 libcv200.dll

Answer 1

How did you get file names ending in .a ? This is non-standard for windows/visual studio and is probably the cause of your problem. Do you have a custom make file that has these names in them ? Did you download a bad versions ?

In OpenCV2.1 - do you have the following files ?

2085888   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\cv210.dll
3890688   4-05-2010   8:11p ----A  c:\OpenCV2.1\bin\cv210d.dll
1069568   4-05-2010   8:06p ----A  c:\OpenCV2.1\bin\cvaux210.dll
2437632   4-05-2010   8:13p ----A  c:\OpenCV2.1\bin\cvaux210d.dll
 940544   4-05-2010   8:08p ----A  c:\OpenCV2.1\bin\cvtest.exe
2201088   4-05-2010   8:04p ----A  c:\OpenCV2.1\bin\cxcore210.dll
3819520   4-05-2010   8:11p ----A  c:\OpenCV2.1\bin\cxcore210d.dll
 567808   4-05-2010   8:06p ----A  c:\OpenCV2.1\bin\cxcoretest.exe
 210944   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\cxts210.dll
 781312   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\highgui210.dll
1630720   4-05-2010   8:12p ----A  c:\OpenCV2.1\bin\highgui210d.dll
 407040   4-05-2010   8:04p ----A  c:\OpenCV2.1\bin\ml210.dll
 869376   4-05-2010   8:11p ----A  c:\OpenCV2.1\bin\ml210d.dll
 100352   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\mltest.exe
 128000   4-05-2010   8:08p ----A  c:\OpenCV2.1\bin\opencv_createsamples.exe
4668416   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\opencv_ffmpeg210.dll
5929984   4-05-2010   8:12p ----A  c:\OpenCV2.1\bin\opencv_ffmpeg210d.dll
 129024   4-05-2010   8:06p ----A  c:\OpenCV2.1\bin\opencv_haartraining.exe
  13312   4-05-2010   8:05p ----A  c:\OpenCV2.1\bin\opencv_performance.exe
 157184   4-05-2010   8:08p ----A  c:\OpenCV2.1\bin\opencv_traincascade.exe

Answer 2

Just add C:\OpenCV2.0\bin into your PATH environment variable

or

When you install OpenCV,

Choose the option, Add OpenCV to the system PATH for current user which is not default one

Answer 3

I just had this problem and found a great website. Basically, goto this website and follow the instructions on the .pdf. This ended up working great for me, so hope it helps you too!

http://nashruddin.com/OpenCV_2_0_Installation_on_Windows_XP_and_Visual_Studio_2008

Answer 4

The ".a" at the end of your DLL files is a problem, and those are there because you didn't use CMAKE to build OpenCV 2.0. Additionally you do not link to the DLL files, you link to the library files, and again, the reason you do not see the correct library files is because you didn't use CMAKE to build OpenCV 2.0. If you want to use OpenCV 2.0 you must build it for it to work correctly in Visual Studio. If you do not want to build it then I would suggest downgrading to OpenCV 1.1pre, it comes pre-built and is much more forgiving in Visual Studio.

Another option (and the one I would recommend) is to abandon OpenCV and go with EmguCV. I have been playing with OpenCV for about a year and things got much easier when I switched to EmguCV because EmguCV works with .NET, so you can use a language like C# that does not come with all the C++ baggage of pointers, header files, and memory allocation problem.

And as for the question of 64bit vs. 32bit, OpenCV does not officially support 64bit. To be on the safe side open your project properties and change the "Platform Target" under the "Build" tab from "Any CPU" to "X86". This should be done any time you do anything with OpenCV, even if you are using a wrapper like EmguCV.

Answer 5

As to @Marc's answer, I don't think VC uses the path from the OS. Did you add the path to VC's library paths. I usually add the DLLs to the project and copy if newer on the build and that works very well for me.

Answer 6

just open the bin folder and copy and paste the .dll files to the folder you are working in..it should fix the problem

Answer 7

Copy all dll and .lib to your project directory. it will help you sur.

Answer 8

thanks mohamed and somebody it has worked copy paste the dll files into the bin folder of ur project if ur using emgu wrapper simple it workded for it'll surely work for u :) :)