opencv的形状匹配及算法C++

OpenCV中的形状匹配算法可以通过计算轮廓的Hu矩来实现，具体步骤如下：

1. 读取并二值化图像，提取目标轮廓：

Mat src = imread("image.jpg");
Mat gray, binary;
cvtColor(src, gray, COLOR_BGR2GRAY);
threshold(gray, binary, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);

vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(binary, contours, hierarchy, RETR_LIST, CHAIN_APPROX_SIMPLE);

2. 计算目标轮廓的Hu矩：

Moments mu = moments(contours[0], false);
double hu[7];
HuMoments(mu, hu);

3. 读取并二值化模板图像，提取模板轮廓：

Mat tpl = imread("template.jpg");
Mat gray_tpl, binary_tpl;
cvtColor(tpl, gray_tpl, COLOR_BGR2GRAY);
threshold(gray_tpl, binary_tpl, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);

vector<vector<Point>> contours_tpl;
vector<Vec4i> hierarchy_tpl;
findContours(binary_tpl, contours_tpl, hierarchy_tpl, RETR_LIST, CHAIN_APPROX_SIMPLE);

4. 计算模板轮廓的Hu矩：

Moments mu_tpl = moments(contours_tpl[0], false);
double hu_tpl[7];
HuMoments(mu_tpl, hu_tpl);

5. 计算目标轮廓和模板轮廓的Hu矩的差异（即Hu矩距离）：

double dist = matchShapes(contours[0], contours_tpl[0], CONTOURS_MATCH_I1, 0);

6. 根据Hu矩距离判断目标轮廓和模板轮廓的相似度：

if (dist < 0.1) {
    cout << "匹配成功！" << endl;
} else {
    cout << "匹配失败！" << endl;
}

完整的代码如下：

#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;

int main() {
    Mat src = imread("image.jpg");
    Mat gray, binary;
    cvtColor(src, gray, COLOR_BGR2GRAY);
    threshold(gray, binary, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);

    vector<vector<Point>> contours;
    vector<Vec4i> hierarchy;
    findContours(binary, contours, hierarchy, RETR_LIST, CHAIN_APPROX_SIMPLE);

    Moments mu = moments(contours[0], false);
    double hu[7];
    HuMoments(mu, hu);

    Mat tpl = imread("template.jpg");
    Mat gray_tpl, binary_tpl;
    cvtColor(tpl, gray_tpl, COLOR_BGR2GRAY);
    threshold(gray_tpl, binary_tpl, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);

    vector<vector<Point>> contours_tpl;
    vector<Vec4i> hierarchy_tpl;
    findContours(binary_tpl, contours_tpl, hierarchy_tpl, RETR_LIST, CHAIN_APPROX_SIMPLE);

    Moments mu_tpl = moments(contours_tpl[0], false);
    double hu_tpl[7];
    HuMoments(mu_tpl, hu_tpl);

    double dist = matchShapes(contours[0], contours_tpl[0], CONTOURS_MATCH_I1, 0);

    if (dist < 0.1) {
        cout << "匹配成功！" << endl;
    } else {
        cout << "匹配失败！" << endl;
    }

    return 0;
}