LBP opencv c++ problem

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Hi, i want to calculate LBP for an image.
i use this code:

C++

cv::Mat LBP(string src_image)
{
	cv::Mat temp_image = imread(src_image.c_str(), 1);
	cv::Mat Image(temp_image.rows, temp_image.cols, CV_8UC1);
	cv::Mat lbp(temp_image.rows, temp_image.cols, CV_8UC1);

	if (temp_image.channels() == 3)
		cvtColor(temp_image, Image, CV_BGR2GRAY);

	imshow("src_image", Image);

	int center = 0;
	int center_lbp = 0;

	for (int row = 1; row < Image.rows; row++)
	{
		for (int col = 1; col < Image.cols; col++)
		{
			center = Image.at<int>(row, col);
			center_lbp = 0;

			if (center <= Image.at<int>(row - 1, col - 1))
				center_lbp += 1;

			if (center <= Image.at<int>(row - 1, col))
				center_lbp += 2;

			if (center <= Image.at<int>(row - 1, col + 1))
				center_lbp += 4;

			if (center <= Image.at<int>(row, col - 1))
				center_lbp += 8;

			if (center <= Image.at<int>(row, col + 1))
				center_lbp += 16;

			if (center <= Image.at<int>(row + 1, col - 1))
				center_lbp += 32;

			if (center <= Image.at<int>(row + 1, col))
				center_lbp += 64;

			if (center <= Image.at<int>(row + 1, col + 1))
				center_lbp += 128;

			cout << "center lbp value: " << center_lbp << endl;
			lbp.at<int>(row, col) = center_lbp;
		}
	}

	imshow("lbp_image", lbp);
	waitKey(0);
	destroyAllWindows();

	return lbp;
}

but it throw an exception "unable to read memory" at this instruction

C++

center = Image.at<int>(row, col);

and this is image for locals when i debug the program
https://dl.dropboxusercontent.com/u/89320576/Capture.PNG[^]

what is the problem??

Posted 11-Jan-15 0:08am

Esraa Saady

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Richard MacCutchan 11-Jan-15 6:37am

What are the values of row and col when the exception is thrown?

Esraa Saady 11-Jan-15 6:53am

128*64

Richard MacCutchan 11-Jan-15 6:57am

Well, since the number of rows is 128, and the number of columns is 64, that would seem to be illegal index values. Although I cannot see how this would happen in those for loops.

Esraa Saady 11-Jan-15 6:59am

what should i do to fix this error?

Richard MacCutchan 12-Jan-15 3:44am

The only thing you can do is to step through the code with your debugger to try and discover how those for loop indices are getting invalid values.

2 solutions

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nv3 · Answer 1 · 2015-01-11T23:50:00

In some of your expressions you try to access pixels with coordinates row+1 and col+1. That is outside the permitted range, as your row and col variables run to Image.rows - 1 respectively Image.cols - 1. The +1 just gets yourself one over the edge.

To fix it, just reduce the loops to

C++

for (int row = 1; row < Image.rows-1; row++)
{
    for (int col = 1; col < Image.cols-1; col++)

mefteh ayda · Answer 2 · 2015-03-25T03:13:00

XML

Mat LBP(Mat src_image)
{
    bool affiche=true;
    cv::Mat Image(src_image.rows, src_image.cols, CV_8UC1);
    cv::Mat lbp(src_image.rows, src_image.cols, CV_8UC1);

    if (src_image.channels() == 3)
        cvtColor(src_image, Image, CV_BGR2GRAY);

    unsigned center = 0;
    unsigned center_lbp = 0;

    for (int row = 1; row < Image.rows-1; row++)
    {
        for (int col = 1; col < Image.cols-1; col++)
        {
            center = Image.at<uchar>(row, col);
            center_lbp = 0;

            if (center <= Image.at<uchar>(row - 1, col - 1))
                center_lbp += 1;

            if (center <= Image.at<uchar>(row - 1, col))
                center_lbp += 2;

            if (center <= Image.at<uchar>(row - 1, col + 1))
                center_lbp += 4;

            if (center <= Image.at<uchar>(row, col - 1))
                center_lbp += 8;

            if (center <= Image.at<uchar>(row, col + 1))
                center_lbp += 16;

            if (center <= Image.at<uchar>(row + 1, col - 1))
                center_lbp += 32;

            if (center <= Image.at<uchar>(row + 1, col))
                center_lbp += 64;

            if (center <= Image.at<uchar>(row + 1, col + 1))
                center_lbp += 128;
            lbp.at<uchar>(row, col) = center_lbp;
        }
    }
 if(affiche == true)
            {
              cv::imshow("image LBP", lbp);
              waitKey(10);
              cv::imshow("grayscale",Image);
              waitKey(10);
            }

            else
            {
              cv::destroyWindow("image LBP");
              cv::destroyWindow("grayscale");
            }

    return lbp;
}
int main()
{
    Mat frame1;
       frame1= imread("path image")
       LBP(frame1);
    return 0;
}

LBP opencv c++ problem

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