Debug_is_block_type_valid(header->_block_use)

Question

I am new to Programming using Visual Studio and openCv. I wrote a simple program to display the red channel of an image, but every time i run the code it throws "DEBUG ASSERTION FAILED" error.

#include 
#include 

#include 

using namespace std;
using namespace cv;

int main() {
    Mat image;
    image = imread("C:/Users/siddartha/Pictures/sample.jpg");
    if (!image.data) {
        cout = 3) {
            vector rgb;
            split(image, rgb);
            namedWindow("r");
            imshow("r", rgb[0]);

        }
    }
    while (1);
    return 0;
}

Error:

Debug Assertion Failed!

Program: ...sual Studio 2015\Projects\sampleOpenCV\Debug\sampleOpenCV.exe
File: minkernel\crts\ucrt\src\appcrt\heap\debug_heap.cpp
Line: 892

Expression: is_block_type_valid(header->_block_use)

Accepted Answer

Are you absolutely sure that the image has been loaded correctly?

I would think that it hasn't been loaded correctly and because of that the vectorrgb is empty and, in turn, the element rgb[0] doesn't exist which triggers the exception ...

A couple of things I noted:

Use slashes (/) for include-statements not backslashes (\), i.e.
```
#include  // Bad!
#include  // Good!
```
In your check
```
if (!image.data) { ... } 
```
do not assume that image.data is set to NULL ornullptr for empty images. Instead check
```
if (!image.empty()) { ... }
```
Make sure that calls to cv::imshow(...) are followed by a call tocv::waitKey( /* delay in ms or 0 to wait for user input */ ), cf. the note in theOpenCV reference.
while (1); -- is that intentional? What you want is probably cv::waitKey( 0 ) (see 3.).

UPDATE:

Make sure the vector rgb has been initialized to the number of channels, i.e.
```
vector rgb(image.channels());
split(image, rgb);
// ...
```

UPDATE 2:

Can you tell me what exactly the error meant ?

Three things:

The default constructor of std::vector creates an empty vector.
Apparently, cv::split() expects the caller, i.e. you, to allocate data for the output. If you fail to do so, it's likely provoke asegmentation fault.
For debug builds some compilers add padding or safety memory around objects in memory which is never to be touched. If this padding memory is altered at runtime, the program "knows" that something bad happened and throws an exception like the one you saw.

I did all the corrections you stated. but now it shows DEBUG Assertion Failure when i press a key in the end to exit. – sidd607 Jan 14 '16 at 13:30
updating the rgb worked for me. Can you tell me what exactly the error meant ? – sidd607 Jan 14 '16 at 15:09

Answer 2

up vote 0 down vote

it is compiling just fine for me. I am on visual-studio-2013.

here you have a case similar to yours, maybe it will help: debug-assertion-failed

editedJan 13 '16 at 8:53

answered Jan 13 '16 at 8:15

Dominik

176 1 1 11

thanks dude, how could i forget about it? – Dominik Jan 13 '16 at 8:35

true, it was wrong hypothesis then : ) – Dominik Jan 13 '16 at 8:54

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Debug_is_block_type_valid(header->_block_use)

Debug Assertion Failed OpenCv is_block_type_valid(header->_block_use)

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