1 /** 2 * @file Morphology_3(Extract_Lines).cpp 3 * @brief Use morphology transformations for extracting horizontal and vertical lines sample code 4 * @author OpenCV team 5 */ 6 7 #include <iostream> 8 #include <opencv2/opencv.hpp> 9 10 using namespace std; 11 using namespace cv; 12 13 int main(int, char** argv) 14 { 15 //! [load_image] 16 // Load the image 17 Mat src = imread(argv[1]); 18 19 // Check if image is loaded fine 20 if(!src.data) 21 cerr << "Problem loading image!!!" << endl; 22 23 // Show source image 24 imshow("src", src); 25 //! [load_image] 26 27 //! [gray] 28 // Transform source image to gray if it is not 29 Mat gray; 30 31 if (src.channels() == 3) 32 { 33 cvtColor(src, gray, CV_BGR2GRAY); 34 } 35 else 36 { 37 gray = src; 38 } 39 40 // Show gray image 41 imshow("gray", gray); 42 //! [gray] 43 44 //! [bin] 45 // Apply adaptiveThreshold at the bitwise_not of gray, notice the ~ symbol 46 Mat bw; 47 adaptiveThreshold(~gray, bw, 255, CV_ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, 15, -2); 48 49 // Show binary image 50 imshow("binary", bw); 51 //! [bin] 52 53 //! [init] 54 // Create the images that will use to extract the horizontal and vertical lines 55 Mat horizontal = bw.clone(); 56 Mat vertical = bw.clone(); 57 //! [init] 58 59 //! [horiz] 60 // Specify size on horizontal axis 61 int horizontalsize = horizontal.cols / 30; 62 63 // Create structure element for extracting horizontal lines through morphology operations 64 Mat horizontalStructure = getStructuringElement(MORPH_RECT, Size(horizontalsize,1)); 65 66 // Apply morphology operations 67 erode(horizontal, horizontal, horizontalStructure, Point(-1, -1)); 68 dilate(horizontal, horizontal, horizontalStructure, Point(-1, -1)); 69 70 // Show extracted horizontal lines 71 imshow("horizontal", horizontal); 72 //! [horiz] 73 74 //! [vert] 75 // Specify size on vertical axis 76 int verticalsize = vertical.rows / 30; 77 78 // Create structure element for extracting vertical lines through morphology operations 79 Mat verticalStructure = getStructuringElement(MORPH_RECT, Size( 1,verticalsize)); 80 81 // Apply morphology operations 82 erode(vertical, vertical, verticalStructure, Point(-1, -1)); 83 dilate(vertical, vertical, verticalStructure, Point(-1, -1)); 84 85 // Show extracted vertical lines 86 imshow("vertical", vertical); 87 //! [vert] 88 89 //! [smooth] 90 // Inverse vertical image 91 bitwise_not(vertical, vertical); 92 imshow("vertical_bit", vertical); 93 94 // Extract edges and smooth image according to the logic 95 // 1. extract edges 96 // 2. dilate(edges) 97 // 3. src.copyTo(smooth) 98 // 4. blur smooth img 99 // 5. smooth.copyTo(src, edges) 100 101 // Step 1 102 Mat edges; 103 adaptiveThreshold(vertical, edges, 255, CV_ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, 3, -2); 104 imshow("edges", edges); 105 106 // Step 2 107 Mat kernel = Mat::ones(2, 2, CV_8UC1); 108 dilate(edges, edges, kernel); 109 imshow("dilate", edges); 110 111 // Step 3 112 Mat smooth; 113 vertical.copyTo(smooth); 114 115 // Step 4 116 blur(smooth, smooth, Size(2, 2)); 117 118 // Step 5 119 smooth.copyTo(vertical, edges); 120 121 // Show final result 122 imshow("smooth", vertical); 123 //! [smooth] 124 125 waitKey(0); 126 return 0; 127 }
