本文以实现行车过程当中的红绿灯识别为目标,核心的内容包括:OpenCV轮廓识别原理以及OpenCV红绿灯识别的实现具体步骤

📍函数原型: findContours( InputOutputArray image, OutputArrayOfArrays contours,
OutputArray hierarchy, int mode,
int method, Point offset=Point());
📍参数:
1️⃣image:单通道图像矩阵,可以是灰度图,但更常用的是二值图像,一般是经过Canny、拉普拉斯等边缘检测算子处理过的二值图像
2️⃣contours: 定义为“vector
> contours”,是一个向量,并且是一个双重向量,向量内每个元素保存了一组由连续的Point点构成的点的集合的向量,每一组Point点集就是一个轮廓。有多少轮廓,向量contours就有多少元素
3️⃣hierarchy: 也是一个向量,向量内每个元素保存了一个包含4个int整型的数组。向量内的元素和轮廓向量contours内的元素是一一对应的,向量的容量相同
4️⃣int mode:
取值一:CV_CHAIN_APPROX_NONE 保存物体边界上所有连续的轮廓点到 contours向量内
取值二:CV_CHAIN_APPROX_SIMPLE 仅保存轮廓的拐点信息,把所有轮廓拐点处的点保存入contours向量内,拐点与拐点之间直线段上的信息点不予保留
取值三和四:CV_CHAIN_APPROX_TC89_L1,CV_CHAIN_APPROX_TC89_KCOS使用teh-Chinl chain 近似算法
5️⃣Point: Point偏移量,所有的轮廓信息相对于原始图像对应点的偏移量,相当于在每一个检测出的轮廓点上加上该偏移量,并且Point还可以是负值!
参数详解引用出处:findContours函数参数详解_-牧野-的博客-CSDN博客_findcontours函数

PS:视频的效果比较好,如果方便的话可以自行外出拍摄取材
- int redCount = 0;
- int greenCount = 0;
-
- Mat frame;
- Mat img;
- Mat imgYCrCb;
- Mat imgGreen;
- Mat imgRed;
-
- // 亮度参数
- double a = 0.3;
- double b = (1 - a) * 125;
-
- VideoCapture capture("C:/Users/86177/Desktop/image/123.mp4");//导入视频的路径
- if (!capture.isOpened())
- {
- cout << "Start device failed!\n" << endl;//启动设备失败!
- return -1;
- }
- // 帧处理
- while (1)
- {
- capture >> frame;
- //调整亮度
- frame.convertTo(img, img.type(), a, b);
-
- //转换为YCrCb颜色空间
- cvtColor(img, imgYCrCb, CV_BGR2YCrCb);
-
- imgRed.create(imgYCrCb.rows, imgYCrCb.cols, CV_8UC1);
- imgGreen.create(imgYCrCb.rows, imgYCrCb.cols, CV_8UC1);
-
- //分解YCrCb的三个成分
- vector
planes; - split(imgYCrCb, planes);
- // 遍历以根据Cr分量拆分红色和绿色
- MatIterator_
it_Cr = planes[1].begin(), - it_Cr_end = planes[1].end
(); - MatIterator_
it_Red = imgRed.begin(); - MatIterator_
it_Green = imgGreen.begin(); -
- for (; it_Cr != it_Cr_end; ++it_Cr, ++it_Red, ++it_Green)
- {
- // RED, 145
- if (*it_Cr > 145 && *it_Cr < 470)
- *it_Red = 255;
- else
- *it_Red = 0;
-
- // GREEN 95
- if (*it_Cr > 95 && *it_Cr < 110)
- *it_Green = 255;
- else
- *it_Green = 0;
- }
- //膨胀和腐蚀
- dilate(imgRed, imgRed, Mat(15, 15, CV_8UC1), Point(-1, -1));
- erode(imgRed, imgRed, Mat(1, 1, CV_8UC1), Point(-1, -1));
- dilate(imgGreen, imgGreen, Mat(15, 15, CV_8UC1), Point(-1, -1));
- erode(imgGreen, imgGreen, Mat(1, 1, CV_8UC1), Point(-1, -1));
-
- redCount = processImgR(imgRed);
- greenCount = processImgG(imgGreen);
- cout << "red:" << redCount << "; " << "green:" << greenCount << endl;
- if(redCount == 0 && greenCount == 0)
- {
- cv::putText(frame, "lights out", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(255, 255, 255), 8, 8, 0);
- }else if(redCount > greenCount)
- {
- cv::putText(frame, "red light", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(0, 0, 255), 8, 8, 0);
- }else{
- cv::putText(frame, "green light", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(0, 255, 0), 8, 8, 0);
- }

- int processImgR(Mat src)
- {
- Mat tmp;
-
- vector
> contours; - vector
hierarchy; - vector
hull; -
- CvPoint2D32f tempNode;
- CvMemStorage* storage = cvCreateMemStorage();
- CvSeq* pointSeq = cvCreateSeq(CV_32FC2, sizeof(CvSeq), sizeof(CvPoint2D32f), storage);
-
- Rect* trackBox;
- Rect* result;
- int resultNum = 0;
-
- int area = 0;
- src.copyTo(tmp);
-
- //提取轮廓
- findContours(tmp, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);
-
- if (contours.size() > 0)
- {
- trackBox = new Rect[contours.size()];
- result = new Rect[contours.size()];
-
- //确定要跟踪的区域
- for (int i = 0; i < contours.size(); i++)
- {
- cvClearSeq(pointSeq);
- // 获取凸包的点集
- convexHull(Mat(contours[i]), hull, true);
- int hullcount = (int)hull.size();
- // 凸包的保存点
- for (int j = 0; j < hullcount - 1; j++)
- {
- tempNode.x = hull[j].x;
- tempNode.y = hull[j].y;
- cvSeqPush(pointSeq, &tempNode);
- }
-
- trackBox[i] = cvBoundingRect(pointSeq);
- }
-
- if (isFirstDetectedR)
- {
- lastTrackBoxR = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- lastTrackBoxR[i] = trackBox[i];
- lastTrackNumR = contours.size();
- isFirstDetectedR = false;
- }
- else
- {
- for (int i = 0; i < contours.size(); i++)
- {
- for (int j = 0; j < lastTrackNumR; j++)
- {
- if (isIntersected(trackBox[i], lastTrackBoxR[j]))
- {
- result[resultNum] = trackBox[i];
- break;
- }
- }
- resultNum++;
- }
- delete[] lastTrackBoxR;
- lastTrackBoxR = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- {
- lastTrackBoxR[i] = trackBox[i];
- }
- lastTrackNumR = contours.size();
- }
-
- delete[] trackBox;
- }
- else
- {
- isFirstDetectedR = true;
- result = NULL;
- }
- cvReleaseMemStorage(&storage);
-
- if (result != NULL)
- {
- for (int i = 0; i < resultNum; i++)
- {
- area += result[i].area();
- }
- }
- delete[] result;
-
- return area;
- }
-
- int processImgG(Mat src)
- {
- Mat tmp;
-
- vector
> contours; - vector
hierarchy; - vector< Point > hull;
-
- CvPoint2D32f tempNode;
- CvMemStorage* storage = cvCreateMemStorage();
- CvSeq* pointSeq = cvCreateSeq(CV_32FC2, sizeof(CvSeq), sizeof(CvPoint2D32f), storage);
-
- Rect* trackBox;
- Rect* result;
- int resultNum = 0;
-
- int area = 0;
-
- src.copyTo(tmp);
- //提取轮廓
- findContours(tmp, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);
-
- if (contours.size() > 0)
- {
- trackBox = new Rect[contours.size()];
- result = new Rect[contours.size()];
-
- // 确定要跟踪的区域
- for (int i = 0; i < contours.size(); i++)
- {
- cvClearSeq(pointSeq);
- // 获取凸包的点集
- convexHull(Mat(contours[i]), hull, true);
- int hullcount = (int)hull.size();
- // 保存凸包的点
- for (int j = 0; j < hullcount - 1; j++)
- {
- tempNode.x = hull[j].x;
- tempNode.y = hull[j].y;
- cvSeqPush(pointSeq, &tempNode);
- }
-
- trackBox[i] = cvBoundingRect(pointSeq);
- }
-
- if (isFirstDetectedG)
- {
- lastTrackBoxG = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- lastTrackBoxG[i] = trackBox[i];
- lastTrackNumG = contours.size();
- isFirstDetectedG = false;
- }
- else
- {
- for (int i = 0; i < contours.size(); i++)
- {
- for (int j = 0; j < lastTrackNumG; j++)
- {
- if (isIntersected(trackBox[i], lastTrackBoxG[j]))
- {
- result[resultNum] = trackBox[i];
- break;
- }
- }
- resultNum++;
- }
- delete[] lastTrackBoxG;
- lastTrackBoxG = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- {
- lastTrackBoxG[i] = trackBox[i];
- }
- lastTrackNumG = contours.size();
- }
-
- delete[] trackBox;
- }
- else
- {
- isFirstDetectedG = true;
- result = NULL;
- }
- cvReleaseMemStorage(&storage);
-
- if (result != NULL)
- {
- for (int i = 0; i < resultNum; i++)
- {
- area += result[i].area();
- }
- }
- delete[] result;
-
- return area;
- }

- //确定两个矩形区域是否相交
- bool isIntersected(Rect r1, Rect r2)
- {
- int minX = max(r1.x, r2.x);
- int minY = max(r1.y, r2.y);
- int maxX = min(r1.x + r1.width, r2.x + r2.width);
- int maxY = min(r1.y + r1.height, r2.y + r2.height);
-
- if (minX < maxX && minY < maxY)
- return true;
- else
- return false;
- }



- #include "opencv2/opencv.hpp"
- #include "opencv2/imgproc.hpp"
- #include
- #include
-
- using namespace std;
- using namespace cv;
-
- // Function headers
- int processImgR(Mat);
- int processImgG(Mat);
- bool isIntersected(Rect, Rect);
-
- // Global variables
- bool isFirstDetectedR = true;
- bool isFirstDetectedG = true;
- Rect* lastTrackBoxR;
- Rect* lastTrackBoxG;
- int lastTrackNumR;
- int lastTrackNumG;
-
- //主函数
- int main()
- {
- int redCount = 0;
- int greenCount = 0;
-
- Mat frame;
- Mat img;
- Mat imgYCrCb;
- Mat imgGreen;
- Mat imgRed;
-
- // 亮度参数
- double a = 0.3;
- double b = (1 - a) * 125;
-
- VideoCapture capture("C:/Users/86177/Desktop/image/123.mp4");//导入视频的路径
- if (!capture.isOpened())
- {
- cout << "Start device failed!\n" << endl;//启动设备失败!
- return -1;
- }
-
- // 帧处理
- while (1)
- {
- capture >> frame;
- //调整亮度
- frame.convertTo(img, img.type(), a, b);
-
- //转换为YCrCb颜色空间
- cvtColor(img, imgYCrCb, CV_BGR2YCrCb);
-
- imgRed.create(imgYCrCb.rows, imgYCrCb.cols, CV_8UC1);
- imgGreen.create(imgYCrCb.rows, imgYCrCb.cols, CV_8UC1);
-
- //分解YCrCb的三个成分
- vector
planes; - split(imgYCrCb, planes);
- // 遍历以根据Cr分量拆分红色和绿色
- MatIterator_
it_Cr = planes[1].begin(), - it_Cr_end = planes[1].end
(); - MatIterator_
it_Red = imgRed.begin(); - MatIterator_
it_Green = imgGreen.begin(); -
- for (; it_Cr != it_Cr_end; ++it_Cr, ++it_Red, ++it_Green)
- {
- // RED, 145
- if (*it_Cr > 145 && *it_Cr < 470)
- *it_Red = 255;
- else
- *it_Red = 0;
-
- // GREEN 95
- if (*it_Cr > 95 && *it_Cr < 110)
- *it_Green = 255;
- else
- *it_Green = 0;
- }
-
- //膨胀和腐蚀
- dilate(imgRed, imgRed, Mat(15, 15, CV_8UC1), Point(-1, -1));
- erode(imgRed, imgRed, Mat(1, 1, CV_8UC1), Point(-1, -1));
- dilate(imgGreen, imgGreen, Mat(15, 15, CV_8UC1), Point(-1, -1));
- erode(imgGreen, imgGreen, Mat(1, 1, CV_8UC1), Point(-1, -1));
-
- redCount = processImgR(imgRed);
- greenCount = processImgG(imgGreen);
- cout << "red:" << redCount << "; " << "green:" << greenCount << endl;
-
- if(redCount == 0 && greenCount == 0)
- {
- cv::putText(frame, "lights out", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(255, 255, 255), 8, 8, 0);
- }else if(redCount > greenCount)
- {
- cv::putText(frame, "red light", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(0, 0, 255), 8, 8, 0);
- }else{
- cv::putText(frame, "green light", Point(40, 150), cv::FONT_HERSHEY_SIMPLEX, 2, cv::Scalar(0, 255, 0), 8, 8, 0);
- }
-
- imshow("video", frame);
- imshow("Red", imgRed);
- imshow("Green", imgGreen);
-
- // Handle with the keyboard input
- if (cvWaitKey(20) == 'q')
- break;
- }
-
- return 0;
- }
-
- int processImgR(Mat src)
- {
- Mat tmp;
-
- vector
> contours; - vector
hierarchy; - vector
hull; -
- CvPoint2D32f tempNode;
- CvMemStorage* storage = cvCreateMemStorage();
- CvSeq* pointSeq = cvCreateSeq(CV_32FC2, sizeof(CvSeq), sizeof(CvPoint2D32f), storage);
-
- Rect* trackBox;
- Rect* result;
- int resultNum = 0;
-
- int area = 0;
- src.copyTo(tmp);
-
- //提取轮廓
- findContours(tmp, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);
-
- if (contours.size() > 0)
- {
- trackBox = new Rect[contours.size()];
- result = new Rect[contours.size()];
-
- //确定要跟踪的区域
- for (int i = 0; i < contours.size(); i++)
- {
- cvClearSeq(pointSeq);
- // 获取凸包的点集
- convexHull(Mat(contours[i]), hull, true);
- int hullcount = (int)hull.size();
- // 凸包的保存点
- for (int j = 0; j < hullcount - 1; j++)
- {
- tempNode.x = hull[j].x;
- tempNode.y = hull[j].y;
- cvSeqPush(pointSeq, &tempNode);
- }
-
- trackBox[i] = cvBoundingRect(pointSeq);
- }
-
- if (isFirstDetectedR)
- {
- lastTrackBoxR = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- lastTrackBoxR[i] = trackBox[i];
- lastTrackNumR = contours.size();
- isFirstDetectedR = false;
- }
- else
- {
- for (int i = 0; i < contours.size(); i++)
- {
- for (int j = 0; j < lastTrackNumR; j++)
- {
- if (isIntersected(trackBox[i], lastTrackBoxR[j]))
- {
- result[resultNum] = trackBox[i];
- break;
- }
- }
- resultNum++;
- }
- delete[] lastTrackBoxR;
- lastTrackBoxR = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- {
- lastTrackBoxR[i] = trackBox[i];
- }
- lastTrackNumR = contours.size();
- }
-
- delete[] trackBox;
- }
- else
- {
- isFirstDetectedR = true;
- result = NULL;
- }
- cvReleaseMemStorage(&storage);
-
- if (result != NULL)
- {
- for (int i = 0; i < resultNum; i++)
- {
- area += result[i].area();
- }
- }
- delete[] result;
-
- return area;
- }
-
- int processImgG(Mat src)
- {
- Mat tmp;
-
- vector
> contours; - vector
hierarchy; - vector< Point > hull;
-
- CvPoint2D32f tempNode;
- CvMemStorage* storage = cvCreateMemStorage();
- CvSeq* pointSeq = cvCreateSeq(CV_32FC2, sizeof(CvSeq), sizeof(CvPoint2D32f), storage);
-
- Rect* trackBox;
- Rect* result;
- int resultNum = 0;
-
- int area = 0;
-
- src.copyTo(tmp);
- //提取轮廓
- findContours(tmp, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);
-
- if (contours.size() > 0)
- {
- trackBox = new Rect[contours.size()];
- result = new Rect[contours.size()];
-
- // 确定要跟踪的区域
- for (int i = 0; i < contours.size(); i++)
- {
- cvClearSeq(pointSeq);
- // 获取凸包的点集
- convexHull(Mat(contours[i]), hull, true);
- int hullcount = (int)hull.size();
- // 保存凸包的点
- for (int j = 0; j < hullcount - 1; j++)
- {
- tempNode.x = hull[j].x;
- tempNode.y = hull[j].y;
- cvSeqPush(pointSeq, &tempNode);
- }
-
- trackBox[i] = cvBoundingRect(pointSeq);
- }
-
- if (isFirstDetectedG)
- {
- lastTrackBoxG = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- lastTrackBoxG[i] = trackBox[i];
- lastTrackNumG = contours.size();
- isFirstDetectedG = false;
- }
- else
- {
- for (int i = 0; i < contours.size(); i++)
- {
- for (int j = 0; j < lastTrackNumG; j++)
- {
- if (isIntersected(trackBox[i], lastTrackBoxG[j]))
- {
- result[resultNum] = trackBox[i];
- break;
- }
- }
- resultNum++;
- }
- delete[] lastTrackBoxG;
- lastTrackBoxG = new Rect[contours.size()];
- for (int i = 0; i < contours.size(); i++)
- {
- lastTrackBoxG[i] = trackBox[i];
- }
- lastTrackNumG = contours.size();
- }
-
- delete[] trackBox;
- }
- else
- {
- isFirstDetectedG = true;
- result = NULL;
- }
- cvReleaseMemStorage(&storage);
-
- if (result != NULL)
- {
- for (int i = 0; i < resultNum; i++)
- {
- area += result[i].area();
- }
- }
- delete[] result;
-
- return area;
- }
-
- //确定两个矩形区域是否相交
- bool isIntersected(Rect r1, Rect r2)
- {
- int minX = max(r1.x, r2.x);
- int minY = max(r1.y, r2.y);
- int maxX = min(r1.x + r1.width, r2.x + r2.width);
- int maxY = min(r1.y + r1.height, r2.y + r2.height);
-
- if (minX < maxX && minY < maxY)
- return true;
- else
- return false;
- }
- 本文主要讲解OpenCV轮廓识别原理以及OpenCV红绿灯识别的实现具体步骤
- OpenCV还是有很多识别的库函数可以用,接下来继续探索,结合生活实际继续做一些有意思的案例
以上就是本文的全部内容啦!如果对您有帮助,麻烦点赞啦!收藏啦!欢迎各位评论区留言!! !