OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cv:: cvtColor, file ..\..\..\..\opencv\modules\imgproc\src\color.cpp, line 3737

Question

Hi I am trying to run this sample code from OpenCV:

#include \"opencv2\\opencv.hpp\"

using namespace cv;

int main(int, char**)
{
    VideoCapture cap(0);          


        

Answer 1

From the conversation in the comments to the question, we saw that VideoCapture gives frame in grayscale. So the call to cvtColor caused the crash.

...
Mat frame;
cap >> frame; // frame is already CV_8UC1
//cvtColor(frame, edges, CV_BGR2GRAY); // so don't to convert here, or crash!
edges = frame.clone(); 
...