前言

最近在网上偶然看到Halcon检测电路连线问题，感觉挺有意思，本人打算用Opencv来实现下，说做就做。

1. 检测步骤

这里主要使用了形态学开闭操作绝对差值进行检测，然后使用轮廓查找与过滤的方法来确定最终检测结果，很简单吧，但是参数设置是个大问题，本人尝试了很多次，才达到比较好的效果，而且通用性感觉不是很好。

2. C++实现

#include <iostream>
#include <opencv2\imgcodecs.hpp>
#include <opencv2\core.hpp>
#include <opencv2\imgproc.hpp>
#include <opencv2\highgui.hpp>
#include <vector>

using namespace cv;

int main()
{
	std::string strImgFile = "C:\\Temp\\common\\Workspace\\Opencv\\images\\detect_broken.png";
	Mat mSrc = imread(strImgFile);
	CV_Assert(!mSrc.empty());

	Mat mGray;
	cvtColor(mSrc, mGray, COLOR_BGR2GRAY);
	CV_Assert(!mGray.empty());

	imshow("gray", mGray);

	Mat mThresh;
	threshold(mGray, mThresh, 0, 255, THRESH_BINARY | THRESH_OTSU);
	CV_Assert(!mThresh.empty());

	imshow("thresh", mThresh);

	Mat kernel = getStructuringElement(MORPH_RECT, Size(5, 5));

	Mat mOpen;
	morphologyEx(mThresh, mOpen, MORPH_OPEN, kernel);
	CV_Assert(!mOpen.empty());

	imshow("open", mOpen);

	Mat mClose;
	morphologyEx(mThresh, mClose, MORPH_CLOSE, kernel);
	CV_Assert(!mClose.empty());

	imshow("close", mClose);

	Mat mDiff;
	absdiff(mOpen, mClose, mDiff);
	CV_Assert(!mDiff.empty());
	imshow("diff", mDiff);

	Mat mSrcCopy = mSrc.clone();
	std::vector<std::vector<Point>> contours;
	findContours(mDiff, contours, RETR_EXTERNAL, CHAIN_APPROX_NONE);
	for (int i = 0; i < contours.size(); i++)
	{
		Point2f center;
		
		double area =  contourArea(contours[i]);
		RotatedRect rr = minAreaRect(contours[i]);
		Rect rect = rr.boundingRect();
		int max = rect.width > rect.height ? rect.width : rect.height;
		int min = rect.width > rect.height ? rect.height : rect.width;
		if (  max/min < 5 && min > 2)
		{
			drawContours(mSrcCopy, contours, i, Scalar(0, 0, 255), -1); 
		}
	}

	imshow("filter", mSrcCopy);

	waitKey(0);
	destroyAllWindows();

	system("pause");
	return 0;
}