Linking error in OpenCV programs when using third party libraries - c++

I am trying to use graph library using opencv.
This is the code that I have written , and am building this on Visual studio 2010.
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include "GraphUtils.h"
using namespace cv;
using namespace std;
int main()
{
float floatArray[4]= {1,1,2,2};
showFloatGraph("Rotation Angle", floatArray, 4 );
return 0;
}
There is no compilation error.
However, I am getting following linking error:
Error 1 error LNK2019: unresolved external symbol _showFloatGraph
referenced in function _main C:\Users\Yam\Documents\Visual Studio
2010\Projects\plot\opencv1\helloworld.obj
Error 2 error LNK1120: 1 unresolved externals C:\Users\Yam\Documents\Visual Studio
2010\Projects\plot\Debug\opencv1.exe
I have put the two files (GraphUtils.h and GraphUtils.c) with my .cpp file.
Why I am getting these compilation errors whenever I am using third party libraries (.c and .h) files, since I get this linking error also when using other library. I asked the question here
In Properties=>Linker=>input=>Additional dependencies , I have added :
opencv_core231d.lib;opencv_highgui231d.lib;opencv_imgproc231d.lib;opencv_features2d231d.lib;opencv_calib3d231d.lib;%(AdditionalDependencies)
And in fact my basic opencv program for image display works fine.
Do I need to do something special when using these libraries. As of now I just copy paste the .c and .h files in the folder where my .cpp file is present. Do I need to do something more ?
Update:
I found that the the file GraphUtils.c has the following code:
// OpenCV
#include <cv.h>
#include <cxcore.h>
#ifdef USE_HIGHGUI
#include <highgui.h>
#endif
I found that the cv.h, cxcore.h and highgui.h are actually present in opencv 2.3.1/opencv folder and so I changed it like this:
#include <opencv/cv.h>
#include <opencv/cxcore.h>
#ifdef USE_HIGHGUI
#include <opencv/highgui.h>
#endif
Unfortunately this gave rise to more linking errors.
Update
The following program works fine.
#include "opencv2/highgui/highgui.hpp"
#include <iostream>
#include<conio.h>
using namespace cv;
using namespace std;
int main( int argc, const char** argv )
{
Mat img = imread("xyz.bmp", CV_LOAD_IMAGE_UNCHANGED); //read the image data in the file "MyPic.JPG" and store it in 'img'
if (img.empty()) //check whether the image is loaded or not
{
cout << "Error : Image cannot be loaded..!!" << endl;
//system("pause"); //wait for a key press
return -1;
}
namedWindow("MyWindow", CV_WINDOW_AUTOSIZE); //create a window with the name "MyWindow"
imshow("MyWindow", img); //display the image which is stored in the 'img' in the "MyWindow" window
waitKey(0); //wait infinite time for a keypress
destroyWindow("MyWindow"); //destroy the window with the name, "MyWindow"
getch();
return 0;
}
But this program always gives error; no header file recognized. so no function would work:
#include "cv.h" //main OpenCV header
#include "highgui.h" //GUI header
int main() {
// declare a new IplImage pointer
IplImage* myimage;
// load an image
myimage = cvLoadImage("sayyidsmile.jpg",1); //change the file name with your own image
//create a new window & display the image
cvNamedWindow("Smile", 1);
cvMoveWindow("Smile", 100, 100);
cvShowImage("Smile", myimage);
//wait for key to close the window
cvWaitKey(0);
cvDestroyWindow( "Smile" );
cvReleaseImage( &myimage );
return 0;
}
Details on Env. Variables
I followed this article to set EVs.
Currently my variables are like this:
Name Value
OpenCV: C:\Users\Yuvue\Desktop\OpenCV2.3.1
INCLUDE: %OPENCV%\build\include
LIB: %OPENCV%\build\x86\vc10\lib
Path: %OPENCV%\build\x86\vc10\bin
Under Properties => VC++ Directories=> Library Directories, I have added the following:
$(OPENCV)\build\x86\vc10\lib
The second program compiles when I explicitly gives path of cv.h in the include. But if I do so with any of the third party libraries when they have used #include, it starts giving linking error (my original question).
Please help me sort this!!

Related

Done building project "Project.vcxproj" -- FAILED

I wrote some lines of code to simply read and write an image and it was working a few days ago, but now Visual Studio gives these errors: "1>Done building project "Lab1_PI.vcxproj" -- FAILED." and it says it was "unable to start the program" and that the system cannot find the file specified.
I also tried to add add _CRT_SECURE_NO_DEPRECATE and _CRT_SECURE_NO_WARNINGS via right-click project->C/C+±>Preprocessor->Preprocessor Definitions, but nothing changed.
Also, here's my code, but it is correct since it was working a few days ago:
#include <iostream>
#include <string>
#include "opencv2\core.hpp"
#include "opencv2\highgui\highgui.hpp"
#include "opencv2\imgproc\imgproc.hpp"
using namespace cv;
using namespace std;
int main(int arc, const char** argv) {
string imgPath = argv[1];
string img2Path = argv[2];
cv::Mat img = imread(imgPath);
if (!img.data) {
cout << "error:no image" << endl;
return -1;
}
imshow("flower image (color)", img);
Mat img2;
cvtColor(img, img2, COLOR_RGB2GRAY);
imwrite(img2Path, img2);
imshow("flower image (grey)", img2);
waitKey(0);
}
I would be really grateful if someone could help me fix this problem because it stops me from using Visual Studio and I really need it for a project!

Suddenly cannot create new openCV applications, windows 10

I have been using openCv for a while, but have just moved to windows 10.
Now, existing applications will compile, but I cannot make a new one.
In a new project (visual studio 2015, release 64)
I am adding all the libs:
opencv_calib3d310.lib
opencv_core310.lib
opencv_features2d310.lib
opencv_flann310.lib
opencv_highgui310.lib
opencv_imgcodecs310.lib
opencv_imgproc310.lib
opencv_ml310.lib
opencv_objdetect310.lib
opencv_photo310.lib
opencv_shape310.lib
opencv_stitching310.lib
opencv_superres310.lib
opencv_ts310.lib
opencv_video310.lib
opencv_videoio310.lib
opencv_videostab310.lib
setting:
D:\opencv-master\build64\lib\Release;%(AdditionalLibraryDirectories)
and
D:\opencv-master\modules\highgui\include
D:\opencv-master\modules\imgcodecs\include
D:\opencv-master\modules\core\include
D:\opencv-master\modules\videoio\include
D:\opencv-master\modules\imgproc\include
%(AdditionalIncludeDirectories)
and adding the most basic:
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include "stdafx.h"
#include <iostream>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
if (argc != 2)
{
cout << " Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], IMREAD_COLOR); // Read the file
if (image.empty()) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl;
return -1;
}
namedWindow("Display window", WINDOW_AUTOSIZE); // Create a window for display.
imshow("Display window", image); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
In visual studio, Intellisense is fine, no red underlines, everything looks good. When I try to compile tho...
'cv': a namespace with this name does not exist
'Mat': undeclared identifier
'image': undeclared identifier
...and many more. It is like it cannot find the libs, but i am linking them correctly, I am sure of it.
Can anyone assist me here?

error C3861: 'getGaborKernel': identifier not found

I am trying to build the following code, but It failed because of the following error
error C3861: 'getGaborKernel': identifier not found
I have included the required header files and lib files. What could be the problem?
#include "stdafx.h"
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <math.h>
using namespace cv;
using namespace std;
int main(int argc, char* argv[])
{
Mat in = imread("1.jpg",0); // load grayscale
Mat dest;
Mat src_f;
in.convertTo(src_f,CV_32F);
extern ostream cerr;
int kernel_size = 31;
double sig = 1, th = 0, lm = 1.0, gm = 0.02, ps = 0;
cv::Mat kernel =
getGaborKernel(cv::Size(kernel_size,kernel_size),sig, th, lm, gm,
ps);
cv::filter2D(src_f, dest, CV_32F, kernel);
cerr << dest(Rect(30,30,10,10)) << endl; // peek into the data
Mat viz;
dest.convertTo(viz,CV_8U,1.0/255.0);
imshow("k",kernel);
imshow("d",viz);
waitKey();
return 0;
}
When C++ misses a prototype it issues an error. Your source obviously didn't include the header file with the appropriate prototype or the prototype is hidden by #ifdefs.
Lookup the Header file that you expect that it contains the prototy of getGaborKernel.
Check the option Show includes to see what header files are actually included. Verify the header found in the first step is in the list.
Check the option Preprocess to a file to see what the preprocessor outputs after processing all #ifdefs in the generated .i file. Check why the prototype isn't in the output.
Uncheck both options after you have found the problem. That's important for the Preprocess to a file option to get a .obj file instead of the .i.

ERROR: identifier "img" is undefined

I'm beginner to openCV. I dowloaded opencv2.4.5 and visual studio express 2012 then i followed this link http://opencv-srf.blogspot.in/2013/05/installing-configuring-opencv-with-vs.html for setup everything in environment variable etc. Then i followed below link http://opencv-srf.blogspot.in/2013/06/load-display-image.html to create sample application. I included proper #include path. But i'm getting error.
#include "stdafx.h"
#include <C:\opencv\build\include\opencv\cv.h>
#include <C:\opencv\build\include\opencv\cxcore.h>
#include <C:\opencv\build\include\opencv\highgui.h>
#include "C:\opencv\build\include\opencv2\highgui\highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, const char** argv )
{
Mat img = imread("MyPic.JPG", CV_LOAD_IMAGE_UNCHANGED); //read the image data in the file "MyPic.JPG" and store it in 'img'
if (img.empty()) //check whether the image is loaded or not
{
cout << "Error : Image cannot be loaded..!!" << endl;
//system("pause"); //wait for a key press
return -1;
}
namedWindow("MyWindow", CV_WINDOW_AUTOSIZE); //create a window with the name "MyWindow"
imshow("MyWindow", img); //display the image which is stored in the 'img' in the "MyWindow" window
waitKey(0); //wait infinite time for a keypress
destroyWindow("MyWindow"); //destroy the window with the name, "MyWindow"
return 0;
}
please do not use an absolute path for the includes, this is totally non-portable.
it should look like this:
// the usual suspects:
#include "opencv2\core\core.hpp" // Mat is defined here.
#include "opencv2\imgproc\imgproc.hpp"
#include "opencv2\highgui\highgui.hpp"
also, to make this work, your "additional include folders" should point to "opencv/build/include"
and avoid the old c-api headers, like cv.h, highgui.h, cxcore.h

Opencv functions can only be invoked in C code fashion but not in C++ fashion

I am really new to Opencv. After downloading and installing Opencv 2.4 according to the instruction, I began writing my first Opencv program, which was basically a copy of the tutorial on the web.
#include <stdio.h>
#include <iostream>
#include <vector>
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;
int main( int argc, char** argv )
{
char* filename = "C:\\Research\abc.pgm";
IplImage *img0;
if( (img0 = cvLoadImage(filename,-1)) == 0 )
return 0;
cvNamedWindow( "image", 0 );
cvShowImage( "image", img0 );
cvWaitKey(0);
cvDestroyWindow("image");
cvReleaseImage(&img0);
return 0;
}
The codes work very well, but you may notice that in the above code invoking Opencv function is in a C code fashion. I therefore decide to proceed with C++ code fashion with the following codes:
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, char** argv )
{
if( argc != 2)
{
cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
However, in this case the program has several link errors although compiling seems fine. The link errors I have received are as follows:
Error 2 error LNK2019: unresolved external symbol "void __cdecl cv::namedWindow(class stlp_std::basic_string<char,class stlp_std::char_traits<char>,class stlp_std::allocator<char> > const &,int)" (?namedWindow#cv##YAXABV?$basic_string#DV?$char_traits#D#stlp_std##V?$allocator#D#2##stlp_std##H#Z) referenced in function _main C:\Research\OpencvTest\OpencvTest.obj
Error 1 error LNK2019: unresolved external symbol "void __cdecl cv::imshow(class stlp_std::basic_string<char,class stlp_std::char_traits<char>,class stlp_std::allocator<char> > const &,class cv::_InputArray const &)" (?imshow#cv##YAXABV?$basic_string#DV?$char_traits#D#stlp_std##V?$allocator#D#2##stlp_std##ABV_InputArray#1##Z) referenced in function _main C:\Research\OpencvTest\OpencvTest.obj
I am quite sure that I have added necessary Opencv libraries in my program (I use VC10), and the additional libraries I have added are as follows:
stl_port.lib
opencv_highgui242d.lib
opencv_core242d.lib
I was wondering what's wrong with my setting. Why does it work for the first program but not the second one? Any ideas will be appreciated. Thanks!
It has something to do with mixing STLPort and MSVC STL. You probably didn't build OpenCV libraries yourself, so they're using VC10 STL. With C interface there's just char* but with C++ interface linker gets confused with std::string in methods. You should see the same result with imread if you cast it's input to string too.
Can I mix STL implementations in my project?