title: OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cv:: cvtColor, file ..\..\..\..\opencv\modules\imgproc\src\color.cpp, line 3737
body: <p>Hi I am trying to run this sample code from OpenCV: </p>
  
  <pre><code>#include "opencv2\opencv.hpp"
  
  using namespace cv;
  
  int main(int, char**)
  {
      VideoCapture cap(0); // open the default camera
      if (!cap.isOpened())  // check if we succeeded
          return -1;
  
      Mat edges;
      namedWindow("edges", 1);
      for (;;)
      {
          Mat frame;
          cap &gt;&gt; frame; // get a new frame from camera
          cvtColor(frame, edges, CV_BGR2GRAY);
          GaussianBlur(edges, edges, Size(7, 7), 1.5, 1.5);
          Canny(edges, edges, 0, 30, 3);
          imshow("edges", edges);
          if (waitKey(30) &gt;= 0) break;
      }
      // the camera will be deinitialized automatically in VideoCapture destructor
      return 0;
  }
  </code></pre>
  
  <p>I am currently using a Windows 7 x64 BootCamp on a Macbook Pro.  I'm running this code with Visual Studios 2013 and OpenCV 2.4.9.  </p>
  
  <p>This is how I've set up my Config Properties: </p>
  
  <pre><code>VC++ Directories: Include Directories: H:\opencv\build\include;$(IncludePath)
  
  Linker:General:Additional Library Directories: H:\opencv\build\x64\vc12\lib;%(AdditionalLibraryDirectories)
  Linker:Input:Additional Dependencies: opencv_calib3d249.lib;opencv_contrib249.lib;opencv_core249.lib;opencv_features2d249.lib;opencv_flann249.lib;opencv_gpu249.lib;opencv_highgui249.lib;opencv_imgproc249.lib;opencv_legacy249.lib;opencv_ml249.lib;opencv_nonfree249.lib;opencv_objdetect249.lib;opencv_ocl249.lib;opencv_photo249.lib;opencv_stitching249.lib;opencv_superres249.lib;opencv_ts249.lib;opencv_video249.lib;opencv_videostab249.lib;%(AdditionalDependencies)
  </code></pre>
  
  <p>When I click on Local Windows Debugger in Release x64 mode I get the following error from Visual Studios:</p>
  
  <blockquote>
    <p>First-chance exception at 0x000007FEFD21B3DD in Project3.exe:
    Microsoft C++ exception: cv::Exception at memory location
    0x000000000019A8A0.</p>
    
    <p>If there is a handler for this exception, the program may be safely
    continued.</p>
  </blockquote>
  
  <p>When I click Break instead (scared to press Continue), a window named Edges does pop up and the camera does turn on since the green light turns on.  But I also get the following error in the command window: </p>
  
  <blockquote>
    <p>OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cv::
    cvtColor, file ........\opencv\modules\imgproc\src\color.cpp, line
    3737</p>
  </blockquote>
  
  <p>I'm pretty new to C++ and Visual Studios, any help would be appreciated. Thanks in advance! </p>