图像矩

Moments moments(InputArray array, bool binaryImage=false )

Parameters:

• array – Raster image (single-channel, 8-bit or floating-point 2D array) or an array ( or ) of 2D points (Point or Point2f ).
• binaryImage – If it is true, all non-zero image pixels are treated as 1’s. The parameter is used for images only.
• moments – Output moments.

C++: void HuMoments(const Moments& m, OutputArray hu)

C++: void HuMoments(const Moments& moments, double hu[7])

Parameters:

• moments – Input moments computed with moments() .
• hu – Output Hu invariants.

 

Code

#include "stdafx.h"#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);/// Function headervoid thresh_callback(int, void* );/** @function main */int main( int argc, char** argv ){	/// Load source image and convert it to gray	src = http://www.mamicode.com/imread("img3.jpg", 1 );	/// Convert image to gray and blur it	cvtColor( src, src_gray, CV_BGR2GRAY );	blur( src_gray, src_gray, Size(3,3) );	/// Create Window	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);}/** @function thresh_callback */void thresh_callback(int, void* ){	Mat canny_output;	vector<vector<Point> > contours;	vector<Vec4i> hierarchy;	/// Detect edges using canny	Canny( src_gray, canny_output, thresh, thresh*2, 3 );	/// Find contours	findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );	/// Get the moments	vector<Moments> mu(contours.size() );	for( int i = 0; i < contours.size(); i++ )	{ mu[i] = moments( contours[i], false ); }	// 获取图像距	///  Get the mass centers:	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 ); }	// 图像重心	/// Draw contours	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 );	}	/// Show in a window	namedWindow( "Contours", CV_WINDOW_AUTOSIZE );	imshow( "Contours", drawing );	/// Calculate the area with the moments 00 and compare with the result of the OpenCV function	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 );	}}

OpenCV Tutorials —— Image Moments