Segmentation fault on loop calling QRCodeDetector, decodeCurved method #19626
Description
System information (version)
- OpenCV => 4.5.1
- Operating System / Platform => Ubuntu 20.04 LTS
- Compiler => cmake 3.16
Detailed description
I am making use of the detection and decoding methods to create a continued detection of curved QR codes on a webcam.
Upon execution of a loop calling the method "decodeCurved" of the class QRCodeDetector, the first iterations run smoothly. However, after a minute or two of execution, a segmentation fault is launched.
The error also affects the detectAndDecodeCurved as it seems to depend on the decodeCurved method.
Segmentation fault error and BackTrace with GDB:
Thread 1 "MinimalExampleW" received signal SIGSEGV, Segmentation fault.
0x00007ffff7f0fae2 in cv::QRDecode::divideIntoEvenSegments(std::vector<std::vector<cv::Point_<float>, std::allocator<cv::Point_<float> > >, std::allocator<std::vector<cv::Point_<float>, std::allocator<cv::Point_<float> > > > >&) () from /usr/local/lib/libopencv_objdetect.so.4.5
(gdb) bt
#0 0x00007ffff7f0fae2 in cv::QRDecode::divideIntoEvenSegments(std::vector<std::vector<cv::Point_<float>, std::allocator<cv::Point_<float> > >, std::allocator<std::vector<cv::Point_<float>, std::allocator<cv::Point_<float> > > > >&) () at /usr/local/lib/libopencv_objdetect.so.4.5
#1 0x00007ffff7f0fe2b in cv::QRDecode::straightenQRCodeInParts() () at /usr/local/lib/libopencv_objdetect.so.4.5
#2 0x00007ffff7f15f17 in cv::QRDecode::preparingCurvedQRCodes() () at /usr/local/lib/libopencv_objdetect.so.4.5
#3 0x00007ffff7f161d5 in cv::QRCodeDetector::decodeCurved[abi:cxx11](cv::_InputArray const&, cv::_InputArray const&, cv::_OutputArray const&) () at /usr/local/lib/libopencv_objdetect.so.4.5
#4 0x00007ffff7f168b0 in cv::QRCodeDetector::detectAndDecodeCurved[abi:cxx11](cv::_InputArray const&, cv::_OutputArray const&, cv::_OutputArray const&) () at /usr/local/lib/libopencv_objdetect.so.4.5
#5 0x000055555555c8a3 in main ()
Steps to reproduce
I provide a minimal example working with a webcam. This example switching the detectAndDecodeCurved method for the detectAndDecode seems to work fine for an extended amount of time, so the problem seems to be on the curved decoder.
MinimalExampleWebcam.cpp
#include <string>
#include <iostream>
#include <atomic>
#include <csignal>
#include <opencv2/opencv.hpp>
namespace {
volatile std::sig_atomic_t gSignalStatus;
void signal_handler(int signal) {
std::cout << "Caught signal Ctrl-Z " << signal << std::endl;
gSignalStatus = signal;
}
} // unnamed namespace
int main(int argc, char *argv[]) {
std::signal(SIGTSTP, signal_handler);
cv::VideoCapture camera;
int deviceID = 0;
camera.open(deviceID);
if (!camera.isOpened()) {
std::puts("ERROR: Could not open camera");
return 1;
}
cv::Mat frame;
while (gSignalStatus != SIGTSTP) {
camera.read(frame);
if (frame.empty()) {
std::puts("Error getting image");
continue;
}
namedWindow( "Frame window", cv::WINDOW_AUTOSIZE );
cv::imshow("Frame window", frame);
cv::waitKey(1);
try{
cv::QRCodeDetector qrDecode = cv::QRCodeDetector();
std::string result = qrDecode.detectAndDecodeCurved(frame);
std::cout << "Result: " << result << std::endl;
} catch (cv::Exception &e) {
std::puts("Caught exception");
}
}
return 0;
}