使用OpenCV C ++查找轮廓中的极点

问题描述

我已尝试实施此代码，但是在我要确定轮廓的最极端时遇到麻烦.

I have tried to implement this code, but I have a trouble when I want to determine the most extreme point of the contour follow this tutorial.

# determine the most extreme points along the contour
    extLeft = tuple(c[c[:, :, 0].argmin()][0])
    extRight = tuple(c[c[:, :, 0].argmax()][0])
    extTop = tuple(c[c[:, :, 1].argmin()][0])
    extBot = tuple(c[c[:, :, 1].argmax()][0])

有人可以帮我解决这个问题吗?

Can anyone help me to solve this problem?

推荐答案

从std::vector<cv::Point>开始，可以将std::max_element和std::min_element与适当的比较器一起使用，该比较器可在x坐标上工作以找到 left 和 right 点，并在y坐标上工作以找到 top 和 bottom 点:

Starting from a std::vector<cv::Point>, you can use std::max_element and std::min_element with an appropriate comparator, that works on x coordinates to find left and right points, and works on y coordinates to find top and bottom points:

// Your points
vector<Point> pts;
...


Point extLeft  = *min_element(pts.begin(), pts.end(),
                      [](const Point& lhs, const Point& rhs) {
                          return lhs.x < rhs.x;
                  });
Point extRight = *max_element(pts.begin(), pts.end(),
                      [](const Point& lhs, const Point& rhs) {
                          return lhs.x < rhs.x;
                  });
Point extTop   = *min_element(pts.begin(), pts.end(),
                      [](const Point& lhs, const Point& rhs) {
                          return lhs.y < rhs.y;
                  });
Point extBot   = *max_element(pts.begin(), pts.end(),
                      [](const Point& lhs, const Point& rhs) {
                          return lhs.y < rhs.y;
                  });

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