opencv - 使用外部摄像头时，Opencv应用程序崩溃

Question

正在使用轮廓进行对象识别。该代码可以很好地处理图像，我修改了代码以使用摄像机输入实时识别对象。笔记本电脑的内置凸轮可以使一切正常运行，但是在使用外接摄像机时几秒钟后会崩溃。外部相机与我使用opencv开发的其他一些应用程序配合良好。该相机是20MP相机。请查看代码，并帮助我找出可能出问题的地方。我的处理器足以应付高分辨率的图像。似乎当我在启动应用程序之前在凸轮前面引入一个不存在的对象时，该应用程序崩溃了。

include <iostream>
include "opencv2/highgui/highgui.hpp"
include "opencv2/imgproc/imgproc.hpp"
using namespace cv; using namespace std; 
int main() 
{
int largest_area = 0; 
int largest_contour_index = 0; 
Rect bounding_rect; 
int x = 0; 
int y = 0; 
VideoCapture xps(0); 
Mat src; 

while (1) 
{

xps.read(src);


vector<vector<Point>> contours; // Vector for storing contour
vector<Vec4i> hierarchy;


Mat thr(src.rows, src.cols, CV_8UC1);
Mat dst(src.rows, src.cols, CV_8UC1, Scalar::all(0));
cvtColor(src, thr, CV_BGR2GRAY); //Convert to gray
threshold(thr, thr, 80, 255, THRESH_BINARY_INV);
findContours(thr, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE); 

for (int i = 0; i< contours.size(); i++) // iterate through each contour.
{
    double a = contourArea(contours[i], false);  //  Find the area of contour
    if (a>largest_area)
    {
        largest_area = a;
        largest_contour_index = i;                
        bounding_rect = boundingRect(contours[i]); 
    }

}


Scalar color(255, 255, 255);
drawContours(dst, contours, largest_contour_index, color, CV_FILLED, 8, hierarchy); 
rectangle(src, bounding_rect, Scalar(0, 255, 0), 1, 8, 0);

x = bounding_rect.x + bounding_rect.width / 2;
y = bounding_rect.y + bounding_rect.height / 2;

circle(src, Point(x, y), 1, Scalar(0, 0, 255));

imshow("src", src);
imshow("largest Contour", dst);
waitKey(2);

}
}

Answer 1

我认为，崩溃是由于可能找不到的轮廓造成的。为避免此问题，请使用标记，如果找到了轮廓，则绘制它们。

bool found = findContours(thr, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE); 

/* for loop */

if(found)
{
  drawContours(dst, contours, largest_contour_index, color, CV_FILLED, 8, hierarchy); 
  rectangle(src, bounding_rect, Scalar(0, 255, 0), 1, 8, 0);

  x = bounding_rect.x + bounding_rect.width / 2;
  y = bounding_rect.y + bounding_rect.height / 2;

  circle(src, Point(x, y), 1, Scalar(0, 0, 255));
}