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cvtColor crash

asked 2012-12-20 20:31:01 -0500

ctagg gravatar image

updated 2012-12-20 21:54:02 -0500

I am getting a crash in Visual Studio 2010 express. Unhandled exception at ..., exception: cv::Exception at memory location ...

Also says: OpenCV Error: Assertion failed (scn == 3 || scn == 4) in unknown function, file ......\modules\imgproc\src\color.cpp, line 3256

Stepping through the code the crash happens at cvtColor line

#include <iostream>
#include <dirent.h>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/nonfree/nonfree.hpp"

int main(int argc, char** argv)

    cv::Mat img_1 = cv::imread( argv[1] );
    cv::Mat img_1_gray;

    cv::cvtColor(img_1, img_1_gray, CV_RGB2GRAY);    

    return 0;

I have also tried the following demo but crashes at the cvtColor line:

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answered 2012-12-21 01:26:28 -0500

Daniil Osokin gravatar image

This assert means, that your source image (img_1) should have 3 or 4 channels for this type of conversion. I'm think, you don't read properly img_1 source image. Check the paths for this image. You can call img_1.empty() to find out was image read or not.
BTW, imread allows you to specify color type of loaded image, as described here, by default it is BGR image, so you should use CV_BGR2GRAY conversion type.

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answered 2012-12-20 20:55:31 -0500

wuling gravatar image

updated 2012-12-20 20:58:23 -0500

Hi i think you must check input image format first. like:

 if (imag_1_gray.type==CV_8UC1) 
 //don't convert color
//convert color

if your os is windows 64 bits. The picture format you think is gray(CV_8UC1) ,but in fact,it's maybe not.

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Asked: 2012-12-20 20:31:01 -0500

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Last updated: Dec 21 '12