一、簡介
二、輪廓最小外接矩形的繪制
1 #include "opencv2/opencv.hpp"
2 using namespace cv; 3
4 void main() 5 { 6 //輪廓最小外接矩形的繪制
7 Mat srcImg = imread("E://00.png"); 8 Mat dstImg = srcImg.clone(); 9 cvtColor(srcImg, srcImg, CV_BGR2GRAY); 10 threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY); //二值化
11 imshow("threshold", srcImg); 12
13 vector<vector<Point>> contours; 14 vector<Vec4i> hierarcy; 15 findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); 16 vector<Rect> boundRect(contours.size()); //定義外接矩形集合
17 vector<RotatedRect> box(contours.size()); //定義最小外接矩形集合
18 Point2f rect[4]; 19 for(int i=0; i<contours.size(); i++) 20 { 21 box[i] = minAreaRect(Mat(contours[i])); //計算每個輪廓最小外接矩形
22 boundRect[i] = boundingRect(Mat(contours[i])); 23 circle(dstImg, Point(box[i].center.x, box[i].center.y), 5, Scalar(0, 255, 0), -1, 8); //繪制最小外接矩形的中心點
24 box[i].points(rect); //把最小外接矩形四個端點復制給rect數組
25 rectangle(dstImg, Point(boundRect[i].x, boundRect[i].y), Point(boundRect[i].x + boundRect[i].width, boundRect[i].y + boundRect[i].height), Scalar(0, 255, 0), 2, 8); 26 for(int j=0; j<4; j++) 27 { 28 line(dstImg, rect[j], rect[(j+1)%4], Scalar(0, 0, 255), 2, 8); //繪制最小外接矩形每條邊
29 } 30 } 31 imshow("dst", dstImg); 32 waitKey(0); 33 }
三、粗略計算物體像素長寬
1 #include "opencv2/opencv.hpp"
2 #include<iostream>
3 using namespace std; 4 using namespace cv; 5
6 void main() 7 { 8 Mat srcImg = imread("E://cup.jpg"); 9 imshow("src", srcImg); 10 Mat dstImg = srcImg.clone(); 11 medianBlur(srcImg, srcImg, 5); 12 GaussianBlur(srcImg, srcImg, Size(3, 3), 0, 0); 13 cvtColor(srcImg, srcImg, CV_BGR2GRAY); 14 threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY_INV); //INV是因為背景白色，物體黑色，需要反轉一下
15 imshow("threshold", srcImg); 16
17 vector<vector<Point>> contours; 18 vector<Vec4i> hierarcy; 19
20 findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); 21 cout<<"num="<<contours.size()<<endl; 22 vector<Rect> boundRect(contours.size()); 23 vector<RotatedRect> box(contours.size()); 24 Point2f rect[4]; 25 for(int i=0; i<contours.size(); i++) 26 { 27 box[i] = minAreaRect(Mat(contours[i])); 28 boundRect[i] = boundingRect(Mat(contours[i])); 29 cout<<box[i].angle<<endl; 30 cout<<box[i].center<<endl; 31 cout<<box[i].size.width<<endl; 32 cout<<box[i].size.height<<endl; 33 circle(dstImg, Point(box[i].center.x, box[i].center.y), 5, Scalar(0, 255, 0), -1, 8); 34
35 //繪制外接矩形和 最小外接矩形（for循環）
36 rectangle(dstImg, Point(boundRect[i].x, boundRect[i].y), Point(boundRect[i].x + boundRect[i].width, boundRect[i].y + boundRect[i].height), Scalar(0, 255, 0), 2, 8); 37 box[i].points(rect);//把最小外接矩形四個端點復制給rect數組
38 for(int j=0; j<4; j++) 39 { 40 line(dstImg, rect[j], rect[(j+1)%4], Scalar(0, 0, 255), 2, 8); 41 } 42
43 char width[20], height[20]; 44 sprintf(width, "width=%0.2f", box[i].size.width); 45 sprintf(height, "height=%0.2f", box[i].size.height); 46 putText(dstImg, width, Point(235, 260), CV_FONT_HERSHEY_COMPLEX_SMALL, 0.85, Scalar(0, 255, 0)); 47 putText(dstImg, height, Point(235, 285), CV_FONT_HERSHEY_COMPLEX_SMALL, 0.85, Scalar(0, 255, 0)); 48
49 } 50 imshow("dst", dstImg); 51 waitKey(0); 52 }
四、傾斜物體矯正提取
1 #include "opencv2/opencv.hpp"
2 #include<iostream>
3 using namespace std; 4 using namespace cv; 5
6 void main() 7 { 8 Mat srcImg = imread("E://qrcode.jpg"); 9 imshow("src", srcImg); 10 Mat dstImg = srcImg.clone(); 11 GaussianBlur(srcImg, srcImg, Size(3, 3), 0, 0); 12 cvtColor(srcImg, srcImg, CV_BGR2GRAY); 13 Canny(srcImg, srcImg, 100, 200);//因為原圖比較復雜，所以需要將canny的值調大，去除不想要的成分 14 //threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY_INV); //二值化也可以實現canny效果,不過在本例中雜絮較多
15 imshow("canny", srcImg); 16 Mat element = getStructuringElement(MORPH_RECT, Size(11, 11), Point(-1, -1)); //定義結構元素
17 dilate(srcImg, srcImg, element); //膨脹
18 imshow("dilate", srcImg); 19 erode(srcImg, srcImg, element); 20 imshow("erode", srcImg); 21
22 vector<vector<Point>> contours; 23 vector<Vec4i> hierarcy; 24 findContours(srcImg, contours, hierarcy, CV_RETR_TREE, CV_CHAIN_APPROX_NONE); 25 vector<Rect> boundRect(contours.size()); 26 vector<RotatedRect> box(contours.size()); 27 Point2f rect[4]; 28 for(int i=0; i<contours.size(); i++) 29 { 30 box[i] = minAreaRect(Mat(contours[i])); 31 boundRect[i] = boundingRect(Mat(contours[i])); 32
33 if(box[i].size.width < 100 || box[i].size.height<100)//篩選
34 continue; 35 rectangle(dstImg, Point(boundRect[i].x, boundRect[i].y), Point(boundRect[i].x + boundRect[i].width, boundRect[i].y + boundRect[i].height), Scalar(0, 255, 0), 2, 8); 36 circle(dstImg, Point(box[i].center.x, box[i].center.y), 5, Scalar(0, 255, 0), -1, 8); 37 box[i].points(rect); 38 for(int j=0; j<4; j++) 39 { 40 line(dstImg, rect[j], rect[(j+1)%4], Scalar(0, 0, 255), 2, 8); 41 } 42
43 float angle; 44 cout<<"angle="<<box[i].angle<<endl; 45 angle = box[i].angle; 46 char width[20], height[20]; 47 sprintf(width, "width=%0.2f", box[i].size.width); 48 sprintf(height, "height=%0.2f", box[i].size.height); 49 putText(dstImg, width, Point(195, 260), CV_FONT_HERSHEY_COMPLEX_SMALL, 0.85, Scalar(0, 255, 0)); 50 putText(dstImg, height, Point(190, 285), CV_FONT_HERSHEY_COMPLEX_SMALL, 0.85, Scalar(0, 255, 0)); 51 imshow("temp", dstImg); 52
53 //利用仿射變換進行旋轉 另一種方法，透視變換
54 if (0< abs(angle) && abs(angle)<=45) 55 angle = angle;//負數，順時針旋轉
56 else if (45< abs(angle) && abs(angle)<90) 57 angle = 90 - abs(angle);//正數，逆時針旋轉
58 Point2f center = box[i].center; //定義旋轉中心坐標
59 double angle0 = angle; 60 double scale = 1; 61 Mat roateM = getRotationMatrix2D(center, angle0, scale); //獲得旋轉矩陣,順時針為負，逆時針為正
62 warpAffine(dstImg, dstImg, roateM, dstImg.size()); //仿射變換 63
64 //保存二維碼
65 int x0=0, y0=0, w0=0, h0=0; 66 x0 = boundRect[i].x; 67 y0 = boundRect[i].y; 68 w0 = boundRect[i].width; 69 h0 = boundRect[i].height; 70 Mat ROI = dstImg(Rect(x0, y0, w0, h0)); 71 imwrite("F://1.jpg", ROI); 72 } 73 imshow("dst", dstImg); 74 waitKey(0); 75 }
