OpenCV Buffer Overflow - c++

Question

I've got myself in a pickle on this project I'm working on. My main objective is to stitch two webcam feeds together and do object detection on them - bounding boxes, etc...the standard stuff.
I can't rid myself of buffer overflows though - the somewhat simplified code below (for readability) compiles x64 and soon after I get a buffer overflow error and this in the console:
"OpenCV Error: Assertion Failed (contour.checkVector(2) >= 0 && (contour.depth() == CV_32F || CV_32S) in unknown function, file...."
If comment out all of the lines that have to do with contours (from findContours to drawBoundingBoxes in main) it compiles and runs fine until I hit the spacebar to stop the program, and then I get another buffer overflow error. I get the same errors when I compile x32 as well, for the record.
Any help? Relevant code/pseudo-code pasted below:
// **defines.h**
//Definitions for anything in all caps, like WIDTH, HEIGHT, ERODEIT, etc...
// **protos.h**
// All function prototypes, nothing else
// **detection.cpp**
/* This is the code that related to background subtraction operations*/
#include <opencv2/opencv.hpp>
#include <iostream>
#include "defines.h"
using namespace std;
using namespace cv;
void initBackgroundSubtractor(BackgroundSubtractorMOG2 &bSub)
{
bSub.set("detectShadows", 1);
}
Mat doBackgroundSubtract(BackgroundSubtractorMOG2 &bSub, Mat panorama)
{
Mat foreground;
bSub.operator()(panorama, foreground);
erode(foreground, foreground, Mat(), Point(-1, -1), ERODEIT, BORDER_DEFAULT);
dilate(foreground, foreground, Mat(), Point(-1, -1), DILATEIT, BORDER_DEFAULT);
return foreground;
}
// **contourOps.cpp**
/* Functions that operate on, filter, or relate to OpenCV contours vectors */
#include <opencv2/opencv.hpp>
#include <vector>
#include <fstream>
#include "defines.h"
using namespace std;
using namespace cv;
/* Returns the centroid of a contour */
Point getCentroid(vector<Point> contour)
{
Point centroid;
Moments m;
m = moments(contour, false);
centroid.x = int(m.m10/m.m00);
centroid.y = int(m.m01/m.m00);
return centroid;
}
/* Draws a rectangle around a contour */
void drawBoundingBoxes(vector<vector<Point>> contours, Mat &img)
{
vector<Rect> boundRect(contours.size());
for(unsigned int j = 0; j < contours.size(); j++)
{
boundRect[j] = boundingRect(contours[j]);
rectangle(img, boundRect[j], Scalar(153,0,76), 2, 8, 0);
}
}
/* Removes contours from a vector if they're smaller than the argument "area" */
void contourSizeTrim (vector<vector<Point>> &contours, int area)
{
vector<vector<Point>>::iterator i = contours.begin();
while(i != contours.end())
{
if(contourArea(*i, false) < area)
i = contours.erase(i);
else
i++;
}
}
/* Removes contours from a vector if they're X % smaller than largest contour in vector */
void contourRelSizeTrim(vector<vector<Point>> &contours, int percent)
{
double maxArea = 0.0;
for(unsigned int i=0; i<contours.size(); i++)
{
if (contourArea(contours[i], false) > maxArea)
maxArea = contourArea(contours[i], false);
}
vector<vector<Point>>::iterator j = contours.begin();
while(j != contours.end())
{
if (contourArea(*j, false) < (double)(percent/100.0)*maxArea)
j = contours.erase(j);
else
j++;
}
}
// **realtimestitch.cpp**
#include <opencv2/opencv.hpp>
#include <opencv2/stitching/stitcher.hpp>
#include <vector>
#include <iostream>
#include "defines.h"
using namespace std;
using namespace cv;
void initStitcher(VideoCapture &capture1, VideoCapture &capture2, Stitcher &stitch)
{
capture1.set(CV_CAP_PROP_FRAME_WIDTH, WIDTH);
capture1.set(CV_CAP_PROP_FRAME_HEIGHT, HEIGHT);
capture2.set(CV_CAP_PROP_FRAME_WIDTH, WIDTH);
capture2.set(CV_CAP_PROP_FRAME_HEIGHT, HEIGHT);
detail::OrbFeaturesFinder *featureFinder = new detail::OrbFeaturesFinder(Size(3,1), 1000, 1.5f, 4);
stitch.setFeaturesFinder (featureFinder);
}
void calcCamTransform(VideoCapture &capture1, VideoCapture &capture2, Stitcher &stitch)
{
int64 t;
Mat fr1, fr2, copy1, copy2;
vector<Mat> imgs;
capture1 >> fr1;
capture2 >> fr2;
fr1.copyTo(copy1);
fr2.copyTo(copy2);
imgs.push_back(copy1);
imgs.push_back(copy2);
stitch.estimateTransform(imgs);
}
Mat doStitch(VideoCapture &capture1, VideoCapture &capture2, Stitcher &stitch)
{
Mat fr1, fr2, copy1, copy2, panorama;
vector<Mat> imgs;
capture1 >> fr1;
capture2 >> fr2;
fr1.copyTo(copy1);
fr2.copyTo(copy2);
imgs.push_back(copy1);
imgs.push_back(copy2);
Stitcher::Status status = stitch.composePanorama(imgs, panorama);
if (status != Stitcher::OK)
cout << "Error Stitching: Code: " << int(status) << endl;
return panorama;
}
// **main.cpp**
#include <opencv2/opencv.hpp>
#include <iostream>
#include <vector>
#include "defines.h"
#include "protos.h"
using namespace cv;
int main()
{
bool doTransform = true, doSizeFilter = true, doRelSizeFilter = true;
Mat pano, fGround;
vector<vector<Point>> contours;
VideoCapture cap1(0);
VideoCapture cap2(1);
Stitcher stitcher = Stitcher::createDefault();
BackgroundSubtractorMOG2 bGround;
initStitcher(cap1, cap2, stitcher);
initBackgroundSubtractor(bGround);
while (true)
{
if (doTransform)
{
calcCamTransform(cap1, cap2, stitcher);
doTransform = !doTransform;
}
pano = doStitch(cap1, cap2, stitcher);
fGround = doBackgroundSubtract(bGround, pano);
findContours(fGround, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);
if (doSizeFilter)
contourSizeTrim(contours, AREATHRESH);
if (doRelSizeFilter)
contourRelSizeTrim(contours, RELSIZEPERCENT);
drawBoundingBoxes(contours, pano);
imshow("Stitched Image", pano);
if(waitKey(1) >= 0)
break;
}
return 0;
}

Answer 1

This is a problem related to OpenCV and VS2012 - on VS2010, there are no problems, and the code runs perfectly!

Answer 2

My opinion about this is that the contour you are trying to do something with an empty vector of contours. Have you verified that? Try a
if (contours.empty()) continue; // or here you can display the image to see if it is empty or not
I had the same problem because I was trying to give an epty vector to cv::IsContourConvex(...) function (see here).