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OpenCV CascadeClassifier Segmentation Fault

asked 2013-07-27 08:27:16 -0500

bonchenko gravatar image

updated 2013-07-28 22:46:40 -0500

This is same question I asked in StackOverflow

I am using OpenCV to detect faces in video. Currently I am using CascadeClassifier class, Haar classifier. When I run cascade.detectmultiscale, my program will run normally and suddenly crash with segmentation fault. I debug using gdb and found out thatProgram received signal SIGSEGV, Segmentation fault.

[Switching to Thread 0xb1841460 (LWP 995)]
0x00099280 in cvRunHaarClassifierCascadeSum(CvHaarClassifierCascade const*, CvPoint, double&, int) () there is problem in cvRunHaarClassifierCascadeSum

Running backtrace, seems like gdb cannot finish the process

#0  0x00099470 in cvRunHaarClassifierCascadeSum(CvHaarClassifierCascade const*, CvPoint, double&, int) ()
#1  0x0009a8be in cvRunHaarClassifierCascade ()
#2  0x0009b28e in cv::HaarDetectObjects_ScaleCascade_Invoker::operator()(cv::Range const&) const ()
#3  0x00175928 in tbb::interface6::internal::start_for<tbb::blocked_range<int>, (anonymous namespace)::ProxyLoopBody, tbb::auto_partitioner con)
()
#4  0x00502f5e in tbb::internal::custom_scheduler<tbb::internal::IntelSchedulerTraits>::local_wait_for_all(tbb::task&, tbb::task*) ()
#5  0x005037d0 in tbb::internal::arena::process(tbb::internal::generic_scheduler&) ()
#6  0x00506c60 in tbb::internal::market::process(rml::job&) ()
#7  0x005078fe in tbb::internal::rml::private_worker::run() ()
#8  0x00507c3a in tbb::internal::rml::private_worker::thread_routine(void*) ()
#9  0xb6fb1cb0 in start_thread () from /usr/lib/libpthread.so.0
#10 0xb6dd6828 in ?? () from /usr/lib/libc.so.6
#11 0xb6dd6828 in ?? () from /usr/lib/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

I tried using the C version of cascade classifier ( the CvHaarClassifierCascade class ), same problem also happens when I run it and debug it. This is the code in case you want to see my implementation:

Detector class

class faceDetector {
    ...
    cv::CascadeClassifier cascade;
    ...
};

Initialization

int initDetector(faceDetector* detect) {
    detect->cascade.load( CASCADE_XML_PATH );
    detect->flags = CV_HAAR_DO_CANNY_PRUNING;
    detect->maxR = 23;
    detect->minNeighbours = 3;
    detect->minSize = cvSize(10, 10);
    detect->maxSize = cvSize(100, 100);
    detect->scaleFactor = 1.1;
    cout << "initDetection finished " << endl;
    return 1;
}

Detection, called in a while loop

int faceDetector::detectFaces(IplImage* img, CvRect** regions) {
    int nFaces = 0; // number of detection considered as face
    IplImage* gray = cvCreateImage( cvSize(img->width, img->height), 8, 1 );
    IplImage* smallImg = cvCreateImage( cvSize( cvRound (img->width/scaleFactor),
                                            cvRound (img->height/scaleFactor)), 8, 1 );
    cvCvtColor(img, gray, CV_BGR2GRAY);
    cvResize(gray, smallImg, CV_INTER_LINEAR);
    cvEqualizeHist(smallImg, smallImg);
    cvClearMemStorage(storage);
    int nx1, nx2, ny1, ny2; // coordinate of detection rectangles

    std::vector<cv::Rect> faces; // list of detection
    cv::Mat msmallimg(smallImg);
    cascade.detectMultiScale( msmallimg, faces, scaleFactor, minNeighbours, flags, minSize, maxSize );

    CvRect* nRects;
    nRects = (CvRect*) malloc(faces.size() * sizeof(CvRect));

    std::vector<cv::Rect>::const_iterator i;

    for (i=faces.begin(); i!=faces.end() ; ++i) {
        if ((i->width <= maxSize.width) && (i->height <= maxSize.height) && (i->width >= minSize.width) && (i->height >= minSize.height) ) {
            nx1 = cvRound( i->x * scaleFactor);
            ny1 = cvRound( i->y * scaleFactor);
            nx2 = cvRound( (i->x + i->width) * scaleFactor);
            ny2 = cvRound( (i->y + i->height) * scaleFactor);           
            nRects[nFaces] = cvRect(nx1, ny1, nx2-nx1, ny2-ny1);
            nFaces++;
        }
    }

    *regions = nRects;
    cvReleaseImage(&gray);
    cvReleaseImage(&smallImg);
    return nFaces;
}

The error always happened after I call

cascade.detectMultiScale( msmallimg, faces, scaleFactor, minNeighbours, flags, minSize, maxSize );

Is this known bugs in OpenCV cascade classifier or I have a bad code? I am confused how to debug further on this problem because it ... (more)

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Comments

Today I tried recompile OpenCV without TBB library, and application runs smoothly. I am thinking this is related to parallelization by TBB. I still looking forward to the solution because without TBB, the application runs 2-3x slower :(

bonchenko gravatar imagebonchenko ( 2013-07-29 01:16:48 -0500 )edit

First of all, try skipping the C -style API and move on to the C++ style API, because your problem could be focussed right there.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-07-29 03:25:25 -0500 )edit

Thanks Steve. I tried your suggestion, changing the all of the code to C++, and still the same problem happened. I get segmentation fault in cascade.detectMultiScale. The gdb and the backtrace is same. Interestingly, I recompile OpenCV without tbb, and the problem vanished... Unfortunately, this cause my application to run 2-3 x slower

bonchenko gravatar imagebonchenko ( 2013-07-30 01:55:28 -0500 )edit

What TBB version are you using? As far as I know, TBB 4.1.3 is used with OpenCV2.4.6 It could be that you are using an old version of it? Also, change your post code with the C++ interface, so we can have a look at it.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-07-30 02:00:49 -0500 )edit

I realize this is a year and a half later, but I just wanted to say that I'm having the exact same issue (running Ubuntu 14.04 on Odroid XU3, and I compiled OpenCV for multithreading ((and I'm using the C++ interface to OpenCV)).

slycheese gravatar imageslycheese ( 2014-12-03 17:01:09 -0500 )edit

I am also having the same crash or very large rect.size() returned. I am using 1280x720 image.

richardgohth gravatar imagerichardgohth ( 2016-01-18 02:05:57 -0500 )edit

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answered 2013-07-30 05:50:02 -0500

bonchenko gravatar image

I do cannot recall the TBB version, all I know is I compile OpenCV with BUILD_TBB and WITH_TBB flag on, in console I see it download a tbb archive which I cannot recall the version. This is my C++ implementation:

Detector class

class faceDetector {
    ...
    cv::CascadeClassifier cascade;
    ...
};

Initialization

int initDetector(faceDetector* detect) {
    detect->cascade.load( CASCADE_XML_PATH );
    detect->flags = CV_HAAR_DO_CANNY_PRUNING;
    detect->maxR = 23;
    detect->minNeighbours = 3;
    detect->minSize = cvSize(10, 10);
    detect->maxSize = cvSize(100, 100);
    detect->scaleFactor = 1.1;
    cout << "initDetection finished " << endl;
    return 1;
}

Detection, called in a while loop

int adaboostDetect::detectObject(Mat img, Rect* regions) {
    int nHeads = 0;

    cv::Mat gray( img.size(), CV_8UC1, cv::Scalar::all(0) );
    cv::Mat smallImg( cv::Size( cvRound (img.cols/scaleFactor),
                            cvRound (img.rows/scaleFactor)), CV_8UC1, cv::Scalar::all(0) );

    cvtColor(img, gray, CV_BGR2GRAY);
    cv::resize(gray, smallImg, smallImg.size(), CV_INTER_LINEAR);
    equalizeHist(smallImg, smallImg);
    int nx1, nx2, ny1, ny2;
    std::vector<cv::Rect> faces;
    cascade.detectMultiScale( smallImg, faces, scaleFactor, minNeighbours, flags, minSize, maxSize );
    std::vector<cv::Rect>::const_iterator i;

    for (i=faces.begin(); i!=faces.end() ; ++i) {
        if ((i->width <= maxSize.width) && (i->height <= maxSize.height) && (i->width >= minSize.width) && (i->height >= minSize.height) ) {
            nx1 = cvRound( i->x * scaleFactor);
            ny1 = cvRound( i->y * scaleFactor);
            nx2 = cvRound( (i->x + i->width) * scaleFactor);
            ny2 = cvRound( (i->y + i->height) * scaleFactor);
            *regions = Rect(nx1, ny1, nx2-nx1, ny2-ny1);
            regions++;
            nHeads++;
        }
    }
    return nHeads;
}
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Comments

Download TBB yourself first, not using the default package that gets downloaded. Then supply links to the corresponding TBB you installed in your CMAKE. That is how i got it work!

StevenPuttemans gravatar imageStevenPuttemans ( 2013-07-30 05:58:25 -0500 )edit
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Asked: 2013-07-27 08:27:16 -0500

Seen: 2,004 times

Last updated: Jul 30 '13