opencv，关于物体检测

关于物体检测

环境：opencv 2.4.11+vs2013

参考：

http://www.cnblogs.com/tornadomeet/archive/2012/06/02/2531705.html

http://www.cnblogs.com/xinyuyuanm/archive/2013/04/29/3050750.html

#include <string>
#include <iostream>
#include <stdio.h>
#include <fstream>
#include<math.h>

#include <opencv2opencv.hpp>
#include <opencv2highguihighgui.hpp>
#include <opencv2imgprocimgproc.hpp>
#include <opencv2corecore.hpp>

using namespace std;
using namespace cv;

#define threshold_diff 20
int main()
{
    Mat src1 = imread("图片1.png"), gray1;
    cvtColor(src1, gray1, COLOR_BGR2GRAY);
    Mat src2 = imread("图片2.png"), gray2;
    cvtColor(src2, gray2, COLOR_BGR2GRAY);
    //降噪
    blur(gray1, gray1, Size(3, 3));
    blur(gray2, gray2, Size(3, 3));

    //二值化
    Mat gray_diff;
    //CvMat *src1, *src2;
    //cvAbsDiff(gray_src_y, gray_src_no, abs_src);
    subtract(gray2, gray1, gray_diff);
    for (int i = 0; i < gray_diff.rows; i++)
    {
        for (int j = 0; j < gray_diff.cols; j++)
        {
            if (abs(gray_diff.at<unsigned char>(i,j)) >= threshold_diff)
                gray_diff.at<unsigned char>(i, j) = 255;
            else
                gray_diff.at<unsigned char>(i, j) = 0;    
        }
    }

    //开运算（膨胀腐蚀算子）
    Mat out;
    Mat element = getStructuringElement(MORPH_RECT, Size(3, 3));
    erode(gray_diff, out, element);
    dilate(out, out, element);

    //查找轮廓
    Mat dst = Mat::zeros(out.size(), CV_8UC3);
    vector<vector<Point>> contours;
    vector<Vec4i> hierarchy;
    findContours(out, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);
    int index = 0, largestComp;
    double maxArea = 0;
    for (; index >= 0; index  = hierarchy[index][0])
    {
        const vector<Point>& c = contours[index];
        double area = fabs(contourArea(Mat(c)));
        if (area >maxArea)
        {
            maxArea = area;
            largestComp = index;

        }
    }
    Scalar color(0, 255, 0);
    drawContours(dst, contours, largestComp, color, CV_FILLED, 8, hierarchy);

    imshow("轮廓图", dst);

    imshow("原图", src1);
    imshow("放入物品", src2);
    imshow("图片差", gray_diff);
    imshow("开运算", out);
    
    waitKey(0);
    system("pause");
    return 0;
}