- /*-----------------------------------
- * 轉(zhuǎn)自：http://www.opencv.org.cn/opencvdoc/2.3.2/html/doc/tutorials/imgproc/shapedescriptors/moments/moments.html
- *----------------------------------*/
- 使用OpenCV函數(shù) moments 計(jì)算圖像所有的矩(最高到3階)
- 使用OpenCV函數(shù) contourArea 來計(jì)算輪廓面積
- 使用OpenCV函數(shù) arcLength 來計(jì)算輪廓或曲線長(zhǎng)度
#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>#include <stdlib.h>using namespace cv;using namespace std;Mat src; Mat src_gray;int thresh = 100;int max_thresh = 255;RNG rng(12345);/// 函數(shù)聲明void thresh_callback(int, void* );/** @主函數(shù) */int main( int argc, char** argv ){ /// 讀入原圖像, 返回3通道圖像數(shù)據(jù) src = imread( argv[1], 1 ); /// 把原圖像轉(zhuǎn)化成灰度圖像并進(jìn)行平滑 cvtColor( src, src_gray, CV_BGR2GRAY ); blur( src_gray, src_gray, Size(3,3) ); /// 創(chuàng)建新窗口 char* source_window = "Source"; namedWindow( source_window, CV_WINDOW_AUTOSIZE ); imshow( source_window, src ); createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback ); thresh_callback( 0, 0 ); waitKey(0); return(0);}/** @thresh_callback 函數(shù) */void thresh_callback(int, void* ){ Mat canny_output; vector<vector<Point> > contours; vector<Vec4i> hierarchy; /// 使用Canndy檢測(cè)邊緣 Canny( src_gray, canny_output, thresh, thresh*2, 3 ); /// 找到輪廓 findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) ); /// 計(jì)算矩 vector<Moments> mu(contours.size() ); for( int i = 0; i < contours.size(); i++ ) { mu[i] = moments( contours[i], false ); } /// 計(jì)算中心矩: vector<Point2f> mc( contours.size() ); for( int i = 0; i < contours.size(); i++ ) { mc[i] = Point2f( mu[i].m10/mu[i].m00 , mu[i].m01/mu[i].m00 ); } /// 繪制輪廓 Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 ); for( int i = 0; i< contours.size(); i++ ) { Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() ); circle( drawing, mc[i], 4, color, -1, 8, 0 ); } /// 顯示到窗口中 namedWindow( "Contours", CV_WINDOW_AUTOSIZE ); imshow( "Contours", drawing ); /// 通過m00計(jì)算輪廓面積并且和OpenCV函數(shù)比較 printf("\t Info: Area and Contour Length \n"); for( int i = 0; i< contours.size(); i++ ) { printf(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f \n", i, mu[i].m00, contourArea(contours[i]), arcLength( contours[i], true ) ); Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() ); circle( drawing, mc[i], 4, color, -1, 8, 0 ); }}
