Question

Hi all i’ve the following code that processes an image. i’m new to c++ and vis studio. the program uses opencv so i’ve downloaded it and made my project point to the necessary libraries in the build config. when i try build the code, it doesn’t seem to recognize the opencv variables. Any ideas why when i’ve added the opencv libs to the build?

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#include <cv.h>
    #include <highgui.h>
    #include <math.h>
    #include <iostream>
    #include "StdAfx.h"

    void sampleImage(const IplImage* arr, float idx0, float idx1, CvScalar& res)
    {
      if(idx0<0 || idx1<0 || idx0>(cvGetSize(arr).height-1) || idx1>(cvGetSize(arr).width-1)){
        res.val[0]=0;
        res.val[1]=0;
        res.val[2]=0;
        res.val[3]=0;
        return;
      }
      float idx0_fl=floor(idx0);
      float idx0_cl=ceil(idx0);
      float idx1_fl=floor(idx1);
      float idx1_cl=ceil(idx1);

      CvScalar s1=cvGet2D(arr,(int)idx0_fl,(int)idx1_fl);
      CvScalar s2=cvGet2D(arr,(int)idx0_fl,(int)idx1_cl);
      CvScalar s3=cvGet2D(arr,(int)idx0_cl,(int)idx1_cl);
      CvScalar s4=cvGet2D(arr,(int)idx0_cl,(int)idx1_fl);
      float x = idx0 - idx0_fl;
      float y = idx1 - idx1_fl;
      res.val[0]= s1.val[0]*(1-x)*(1-y) + s2.val[0]*(1-x)*y + s3.val[0]*x*y + s4.val[0]*x*(1-y);
      res.val[1]= s1.val[1]*(1-x)*(1-y) + s2.val[1]*(1-x)*y + s3.val[1]*x*y + s4.val[1]*x*(1-y);
      res.val[2]= s1.val[2]*(1-x)*(1-y) + s2.val[2]*(1-x)*y + s3.val[2]*x*y + s4.val[2]*x*(1-y);
      res.val[3]= s1.val[3]*(1-x)*(1-y) + s2.val[3]*(1-x)*y + s3.val[3]*x*y + s4.val[3]*x*(1-y);
    }

    float xscale;
    float yscale;
    float xshift;
    float yshift;

    float getRadialX(float x,float y,float cx,float cy,float k){
      x = (x*xscale+xshift);
      y = (y*yscale+yshift);
      float res = x+((x-cx)*k*((x-cx)*(x-cx)+(y-cy)*(y-cy)));
      return res;
    }

    float getRadialY(float x,float y,float cx,float cy,float k){
      x = (x*xscale+xshift);
      y = (y*yscale+yshift);
      float res = y+((y-cy)*k*((x-cx)*(x-cx)+(y-cy)*(y-cy)));
      return res;
    }

    float thresh = 1;
    float calc_shift(float x1,float x2,float cx,float k){
      float x3 = x1+(x2-x1)*0.5;
      float res1 = x1+((x1-cx)*k*((x1-cx)*(x1-cx)));
      float res3 = x3+((x3-cx)*k*((x3-cx)*(x3-cx)));

      //  std::cerr<<"x1: "<<x1<<" - "<<res1<<" x3: "<<x3<<" - "<<res3<<std::endl;

      if(res1>-thresh && res1 < thresh)
        return x1;
      if(res3<0){
        return calc_shift(x3,x2,cx,k);
      }
      else{
        return calc_shift(x1,x3,cx,k);
      }
    }

    int main(int argc, char** argv)
    {
      IplImage* src = cvLoadImage( argv[1], 1 );
      IplImage* dst = cvCreateImage(cvGetSize(src),src->depth,src->nChannels);
      IplImage* dst2 = cvCreateImage(cvGetSize(src),src->depth,src->nChannels);
      float K=atof(argv[3]);
      float centerX=atoi(argv[4]);
      float centerY=atoi(argv[5]);
      int width = cvGetSize(src).width;
      int height = cvGetSize(src).height;

      xshift = calc_shift(0,centerX-1,centerX,K);
      float newcenterX = width-centerX;
      float xshift_2 = calc_shift(0,newcenterX-1,newcenterX,K);

      yshift = calc_shift(0,centerY-1,centerY,K);
      float newcenterY = height-centerY;
      float yshift_2 = calc_shift(0,newcenterY-1,newcenterY,K);
      //  scale = (centerX-xshift)/centerX;
      xscale = (width-xshift-xshift_2)/width;
      yscale = (height-yshift-yshift_2)/height;

      std::cerr<<xshift<<" "<<yshift<<" "<<xscale<<" "<<yscale<<std::endl;
      std::cerr<<cvGetSize(src).height<<std::endl;
      std::cerr<<cvGetSize(src).width<<std::endl;

      for(int j=0;j<cvGetSize(dst).height;j++){
        for(int i=0;i<cvGetSize(dst).width;i++){
          CvScalar s;
          float x = getRadialX((float)i,(float)j,centerX,centerY,K);
          float y = getRadialY((float)i,(float)j,centerX,centerY,K);
          sampleImage(src,y,x,s);
          cvSet2D(dst,j,i,s);

        }
      }
    #if 0
      cvNamedWindow( "Source1", 1 );
      cvShowImage( "Source1", dst);
      cvWaitKey(0);
    #endif

      cvSaveImage(argv[2],dst,0);

    #if 0
      for(int j=0;j<cvGetSize(src).height;j++){
        for(int i=0;i<cvGetSize(src).width;i++){
          CvScalar s;
          sampleImage(src,j+0.25,i+0.25,s);
          cvSet2D(dst,j,i,s);
        }
      }

      cvNamedWindow( "Source1", 1 );
      cvShowImage( "Source1", src);
      cvWaitKey(0);

    #endif  

}

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1>------ Build started: Project: sherize, Configuration: Debug Win32 ------
1>  sherize.cpp
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(1): warning C4627: '#include <cv.h>': skipped when looking for precompiled header use
1>          Add directive to 'StdAfx.h' or rebuild precompiled header
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(2): warning C4627: '#include <highgui.h>': skipped when looking for precompiled header use
1>          Add directive to 'StdAfx.h' or rebuild precompiled header
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(3): warning C4627: '#include <math.h>': skipped when looking for precompiled header use
1>          Add directive to 'StdAfx.h' or rebuild precompiled header
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(4): warning C4627: '#include <iostream>': skipped when looking for precompiled header use
1>          Add directive to 'StdAfx.h' or rebuild precompiled header
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(7): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(7): error C2143: syntax error : missing ',' before '*'
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'idx0' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'idx1' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'idx0' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'arr' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2228: left of '.height' must have class/struct/union
1>          type is ''unknown-type''
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'idx1' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2065: 'arr' : undeclared identifier
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C2228: left of '.width' must have class/struct/union
1>          type is ''unknown-type''
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C3861: 'cvGetSize': identifier not found
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(9): error C3861: 'cvGetSize': identifier not found
1>c:\users\mat\documents\visual studio 2010\projects\sherize\sherize\sherize.cpp(10): error C2065: 'res' : undeclared identifier
1>c:\

Answer 1

It’s because you’ve put the #include "stdafx.h" after the other headers. This is VC++’s (default) precompiled header marker – it discards everything before this include and loads its precompiled header state instead, i.e. it’s ignoring the cv.h include here.

This means that you should either move the stdafx.h include to the top of the file or move the #include <cv.h> etc. into stdafx.h. If you want to include them in all of the files in your project and they’re not likely to change between builds then adding them to stdafx.h will include them in the precompiled headers and they’ll be automatically (and efficiently) available for all of your sources in the project.