c++写一个边缘提取算法，不要调用现成库

好的，我可以帮你写一个C++的边缘提取算法。下面是代码实现：

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

int main(int argc, char** argv) {
    if (argc != 2) {
        cerr << "Usage: " << argv[0] << " <image_path>" << endl;
        return EXIT_FAILURE;
    }
    Mat image = imread(argv[1], IMREAD_GRAYSCALE);
    if (image.empty()) {
        cerr << "Failed to open image file: " << argv[1] << endl;
        return EXIT_FAILURE;
    }
    Mat edges(image.size(), CV_8U);
    for (int y = 1; y < image.rows - 1; ++y) {
        for (int x = 1; x < image.cols - 1; ++x) {
            int gx = image.at<uchar>(y - 1, x + 1) - image.at<uchar>(y - 1, x - 1)
                + 2 * image.at<uchar>(y, x + 1) - 2 * image.at<uchar>(y, x - 1)
                + image.at<uchar>(y + 1, x + 1) - image.at<uchar>(y + 1, x - 1);
            int gy = image.at<uchar>(y + 1, x - 1) - image.at<uchar>(y - 1, x - 1)
                + 2 * image.at<uchar>(y + 1, x) - 2 * image.at<uchar>(y - 1, x)
                + image.at<uchar>(y + 1, x + 1) - image.at<uchar>(y - 1, x + 1);
            int val = sqrt(gx * gx + gy * gy);
            edges.at<uchar>(y, x) = val > 255 ? 255 : val;
        }
    }
    imshow("Edges", edges);
    waitKey(0);
    return EXIT_SUCCESS;
}

这个算法使用Sobel算子进行边缘检测，并通过计算x和y方向上的梯度来确定每个像素的强度。然后，将这些强度的平方相加并取平方根以获取最终的像素值。如果该值大于255，则将其截断为255。最后，使用OpenCV库显示提取的边缘。