load image with openCV Mat c++

Question

I want to load an image using Mat in openCV

My code is:

Mat I = imread("C:/images/apple.jpg", 0);
namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", I );

I am getting the following error in a message box:

Unhandled exception at 0x70270149 in matching.exe: 0xC0000005: Access violation 
reading location 0xcccccccc.

Please note that I am including:

#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#include <iostream>
#include <math.h>

score 15 · Answer 1 · edited May 23 '17 at 11:53

15

I've talked about this so many times before, I guess it's pointless to do it again, but code defensively: if a method/function call can fail, make sure you know when it happens:

Mat I = imread("C:\\images\\apple.jpg", 0);
if (I.empty())
{
    std::cout << "!!! Failed imread(): image not found" << std::endl;
    // don't let the execution continue, else imshow() will crash.
}

namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", I ); 
waitKey(0);

Note that Windows' path uses backslash \ instead of the standard / used on *nix systems. You need to escape the backslash when passing the filename: C:\\images\\apple.jpg

Calling waitKey() is mandatory if you use imshow().

EDIT:

If it's cv::imread() that is throwing the exception the only solution I know to work is downloading OpenCV sources and building it on the machine, since re-installing OpenCV doesn't fix the issue.

edited May 23 '17 at 11:53

Community

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answered Apr 19 '13 at 17:09

karlphillip

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@ karlphillip - even with your answer I am having the same problem. – vidzz Apr 19 '13 at 17:22
Unhandled exception at 0x70270149 in matching.exe: 0xC0000005: Access violation reading location 0xcccccccc.(displayed in a message box) – vidzz Apr 19 '13 at 17:32
1

If it's `cv::imread()` I've seen this kind of exception being thrown before. The only solution was to download OpenCV sources and COMPILE it on the machine. Re-installing OpenCV didn't fix the problem. – karlphillip Apr 19 '13 at 17:48
@karlphillip If we want to read many images from different folder than what should we do for that ? – Jul 31 '13 at 17:17
@Wish_2_fly If we want to store several different numbers, how do we do that in a program? `int n1 = 10; int n2 = 20; int n3 = 30; ...` – karlphillip Jul 31 '13 at 18:11
@karlphillip i know in a loop , `for(int n1=0;n1<=10;n1++)` but when i did it in my program , like ; `Mat T=imread("C:\Pick")` and than loop it , it didn't work , here is my question http://stackoverflow.com/questions/17971530/how-to-get-the-area-of-the-image-and-equalize-all-the-images – Jul 31 '13 at 21:42

Martin Beckett · Answer 2 · 2013-04-19T16:57:29.513

2

Have you checked that I exists after imread? Perhaps the file read failed

After reading a file do if ( I.empty() ) to check if it failed

edited Apr 19 '13 at 16:57

answered Apr 19 '13 at 16:42

Martin Beckett

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@ Martin Beckett yes, there is image "apple.jpg"in the link C:/images/apple.jpg – vidzz Apr 19 '13 at 16:46
1

Yes but what does "I.empty()" return? You might not have permission, the file migth be corrupt, you might not have the jpeg.dll etc etcv – Martin Beckett Apr 19 '13 at 16:56
@ Martin Beckett I am getting the above mentioned error- May be I do not have the library or I am wrongly performing the includes. please help me. – vidzz Apr 19 '13 at 17:15

score 2 · Answer 3 · answered Apr 19 '13 at 16:43

2

I don't know why you don't have include problem because normally it .hpp file so you're suppose to do

#include <opencv2/highgui/highgui.hpp>
#include <opencv2\core\eigen.hpp>

But your code seems good but add a cv::waitKey(0); after your imshow.

answered Apr 19 '13 at 16:43

Vuwox

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As @Martin Beckett said, can be just because C:/Images/apple didn't exist so your Mat is empty. So do if(!I.empty()). – Vuwox Apr 19 '13 at 16:44
@ Alexandre Bizeau when I copy and paste your include I am getting this error "fatal error C1083: Cannot open include file: 'opencv2/highgui/highgui.hpp'" – vidzz Apr 19 '13 at 16:51
Does not necessarily copy exactly what I put because your Include Directories is maybe not set as mine. As I can see with your. You maybe just need to do #include or maybe #include . Depend how you set the folder and your project properties – Vuwox Apr 19 '13 at 16:53

score 0 · Answer 4 · answered May 09 '13 at 09:44

0

Are you using visual studio 2010 to run the OpenCV code? If so, try compiling in Release mode.

answered May 09 '13 at 09:44

Les_Salantes

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score 0 · Answer 5 · answered Nov 16 '19 at 05:57

0

As pointed out by @karlphillip, however trivial it may sound but this statement " You need to escape the backslash when passing the filename: C:\images\apple.jpg" is really important.

answered Nov 16 '19 at 05:57

user2580731

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2

load image with openCV Mat c++

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