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| 1 | +//Exercises_9_4.cpp Exercises at end of Chapter 9 |
| 2 | + |
| 3 | +#include <opencv2/opencv.hpp> |
| 4 | +#include <iostream> |
| 5 | + |
| 6 | +using namespace cv; |
| 7 | +using namespace std; |
| 8 | + |
| 9 | +void help(const char **argv) { |
| 10 | + cout << "\n\n" |
| 11 | + << "This program solves the Exercise 4、5 at the end of Chapter 9 \n" |
| 12 | + << "Call:\n" |
| 13 | + << argv[0] << " <path/image_name1>" << " <path/image_name2>\n\n" |
| 14 | + << "For example: ./" << argv[0] << " ../left.jpg "<< " ../left.jpg\n" |
| 15 | + << endl; |
| 16 | +} |
| 17 | + |
| 18 | +int main( int argc, const char** argv ) |
| 19 | +{ |
| 20 | + help(argv); |
| 21 | + if(argc < 3) { |
| 22 | + cout << "\nERROR: You had too few parameters.\n" << endl; |
| 23 | + return -1; |
| 24 | + } |
| 25 | + |
| 26 | + /************************************************************************/ |
| 27 | + /* 1.In this exercise, we learn to experiment with parameters by setting good low |
| 28 | + Thresh and highThresh values in cv::Canny(). Load an image with suitably |
| 29 | + interesting line structures. We’ll use three different high:low threshold settings of |
| 30 | + 1.5:1, 2.75:1, and 4:1. |
| 31 | + a. Report what you see with a high setting of less than 50. |
| 32 | + b. Report what you see with high settings between 50 and 100. |
| 33 | + c. Report what you see with high settings between 100 and 150. |
| 34 | + d. Report what you see with high settings between 150 and 200. |
| 35 | + e. Report what you see with high settings between 200 and 250. |
| 36 | + f. Summarize your results and explain what happens as best you can. */ |
| 37 | + /************************************************************************/ |
| 38 | + Mat src = imread(argv[1],IMREAD_GRAYSCALE); |
| 39 | + Mat dst; |
| 40 | + |
| 41 | + int iHighThresh = 50; |
| 42 | + Canny(src,dst,static_cast<int>(iHighThresh/1.5),iHighThresh); |
| 43 | + imshow("iHighThresh is 50 and high:low is 1.5:1",dst); |
| 44 | + Canny(src,dst,static_cast<int>(iHighThresh/2.75),iHighThresh); |
| 45 | + imshow("iHighThresh is 50 and high:low is 2.75:1",dst); |
| 46 | + Canny(src,dst,static_cast<int>(iHighThresh/4),iHighThresh); |
| 47 | + imshow("iHighThresh is 50 and high:low is 4:1",dst); |
| 48 | + |
| 49 | + iHighThresh = (50+100)/2; |
| 50 | + Canny(src,dst,static_cast<int>(iHighThresh/1.5),iHighThresh); |
| 51 | + imshow("iHighThresh is (50+100)/2 and high:low is 1.5:1",dst); |
| 52 | + Canny(src,dst,static_cast<int>(iHighThresh/2.75),iHighThresh); |
| 53 | + imshow("iHighThresh is (50+100)/2 and high:low is 2.75:1",dst); |
| 54 | + Canny(src,dst,static_cast<int>(iHighThresh/4),iHighThresh); |
| 55 | + imshow("iHighThresh is (50+100)/2 and high:low is 4:1",dst); |
| 56 | + |
| 57 | + iHighThresh = (100+150)/2; |
| 58 | + Canny(src,dst,static_cast<int>(iHighThresh/1.5),iHighThresh); |
| 59 | + imshow("iHighThresh is (100+150)/2 and high:low is 1.5:1",dst); |
| 60 | + Canny(src,dst,static_cast<int>(iHighThresh/2.75),iHighThresh); |
| 61 | + imshow("iHighThresh is (100+150)/2 and high:low is 2.75:1",dst); |
| 62 | + Canny(src,dst,static_cast<int>(iHighThresh/4),iHighThresh); |
| 63 | + imshow("iHighThresh is (100+150)/2 and high:low is 4:1",dst); |
| 64 | + |
| 65 | + iHighThresh = (150+200)/2; |
| 66 | + Canny(src,dst,static_cast<int>(iHighThresh/1.5),iHighThresh); |
| 67 | + imshow("iHighThresh is (150+200)/2 and high:low is 1.5:1",dst); |
| 68 | + Canny(src,dst,static_cast<int>(iHighThresh/2.75),iHighThresh); |
| 69 | + imshow("iHighThresh is (150+200)/2 and high:low is 2.75:1",dst); |
| 70 | + Canny(src,dst,static_cast<int>(iHighThresh/4),iHighThresh); |
| 71 | + imshow("iHighThresh is (150+200)/2 and high:low is 4:1",dst); |
| 72 | + |
| 73 | + iHighThresh = (200+250)/2; |
| 74 | + Canny(src,dst,static_cast<int>(iHighThresh/1.5),iHighThresh); |
| 75 | + imshow("iHighThresh is (200+250)/2 and high:low is 1.5:1",dst); |
| 76 | + Canny(src,dst,static_cast<int>(iHighThresh/2.75),iHighThresh); |
| 77 | + imshow("iHighThresh is (200+250)/2 and high:low is 2.75:1",dst); |
| 78 | + Canny(src,dst,static_cast<int>(iHighThresh/4),iHighThresh); |
| 79 | + imshow("iHighThresh is (200+250)/2 and high:low is 4:1",dst); |
| 80 | + |
| 81 | + /************************************************************************/ |
| 82 | + /* 2. Load an image containing clear lines and circles such as a side view of a bicycle. |
| 83 | + Use the Hough line and Hough circle calls and see how they respond to your |
| 84 | + image. */ |
| 85 | + /************************************************************************/ |
| 86 | + Mat src = imread(argv[1],IMREAD_GRAYSCALE);//a bike in gray |
| 87 | + GaussianBlur( src, src, Size(9, 9), 2, 2 ); |
| 88 | + Mat temp; |
| 89 | + vector<Vec4i> linesP; |
| 90 | + vector<Vec3f> circles; |
| 91 | + //first find the canny edge |
| 92 | + Canny(src,temp,50,200); |
| 93 | + //find lines |
| 94 | + HoughLinesP(temp,linesP,1,CV_PI/180,80,50,10); |
| 95 | + //find circles |
| 96 | + HoughCircles( src, circles, CV_HOUGH_GRADIENT, 1, src.rows/8, 200, 100, 0, 0 ); |
| 97 | + //draw lines and circles in the source image |
| 98 | + for (int i = 0;i<linesP.size();i++) |
| 99 | + { |
| 100 | + Vec4i l = linesP[i]; |
| 101 | + line(src,Point(l[0],l[1]),Point(l[2],l[3]),Scalar(255)); |
| 102 | + } |
| 103 | + |
| 104 | + for( size_t i = 0; i < circles.size(); i++ ) |
| 105 | + { |
| 106 | + Point center(cvRound(circles[i][0]), cvRound(circles[i][1])); |
| 107 | + int radius = cvRound(circles[i][2]); |
| 108 | + // circle center |
| 109 | + circle( src, center, 3, Scalar(255,255,255), -1, 8, 0 ); |
| 110 | + // circle outline |
| 111 | + circle( src, center, radius, Scalar(255,255,255), 1, 8, 0 ); |
| 112 | + } |
| 113 | + |
| 114 | + /*11. Create an image with a 20 × 20 square in it. Rotate it to an arbitrary angle. Take a |
| 115 | + distance transform of this image. Create a 20 × 20 square shape. Use the distance |
| 116 | + transform image to algorithmically overlay the shape onto the rotated square in |
| 117 | + the image you made.*/ |
| 118 | + // create a 20 × 20 square |
| 119 | + Mat matBoard = Mat(500,500,CV_8UC3,Scalar(0)); |
| 120 | + rectangle(matBoard,Rect(250,250,20,20),Scalar(255,255,255),-1); |
| 121 | + // create an arbitary angle |
| 122 | + cv::RNG rng = cv::theRNG(); |
| 123 | + float fDegree = rng.uniform(0,360); |
| 124 | + Mat rotMatS = getRotationMatrix2D(Point(250,250), fDegree, 1.0); |
| 125 | + warpAffine(matBoard, matBoard, rotMatS, matBoard.size(), 1, 0, Scalar(0,0,0)); |
| 126 | + //solove the problem |
| 127 | + Mat matDistance; |
| 128 | + cvtColor(matBoard,gray,COLOR_BGR2GRAY); |
| 129 | + threshold(gray,gray,100,255,CV_THRESH_BINARY); |
| 130 | + distanceTransform(gray,matDistance,CV_DIST_L2,3); |
| 131 | + //find the center corners |
| 132 | + double minVal; |
| 133 | + double maxVal2; |
| 134 | + Point minLoc,maxLoc; |
| 135 | + minMaxLoc( matDistance, &minVal, &maxVal2, &minLoc, &maxLoc, matDistance>0); |
| 136 | + //draw the result |
| 137 | + circle(matBoard,maxLoc,1,Scalar(0),1); |
| 138 | + circle(matBoard,minLoc,2,Scalar(255),2); |
| 139 | + rectangle(matBoard,Rect(maxLoc.x - 10,maxLoc.y - 10,20,20),Scalar(0,0,255),-1); |
| 140 | + return 0; |
| 141 | +} |
| 142 | + |
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