c语言实现sobel算子

以下是使用C语言实现Sobel算子的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define WIDTH 512
#define HEIGHT 512

int main()
{
    // 读取图像
    FILE* fp;
    fp = fopen("lena.raw", "rb");
    unsigned char* img = (unsigned char*)malloc(sizeof(unsigned char) * WIDTH * HEIGHT);
    fread(img, sizeof(unsigned char), WIDTH * HEIGHT, fp);
    fclose(fp);

    // Sobel算子
    int sobel_x[3][3] = {{-1, 0, 1}, {-2, 0, 2}, {-1, 0, 1}};
    int sobel_y[3][3] = {{1, 2, 1}, {0, 0, 0}, {-1, -2, -1}};

    unsigned char* res = (unsigned char*)malloc(sizeof(unsigned char) * WIDTH * HEIGHT);
    int pixel_x, pixel_y, pixel;
    int gx, gy, g;
    for (int i = 1; i < HEIGHT - 1; i++) {
        for (int j = 1; j < WIDTH - 1; j++) {
            gx = gy = 0;
            for (int k = -1; k <= 1; k++) {
                for (int l = -1; l <= 1; l++) {
                    pixel = *(img + (i + k) * WIDTH + (j + l));
                    gx += sobel_x[k + 1][l + 1] * pixel;
                    gy += sobel_y[k + 1][l + 1] * pixel;
                }
            }
            g = sqrt(gx * gx + gy * gy);
            *(res + i * WIDTH + j) = (unsigned char)g;
        }
    }

    // 输出图像
    fp = fopen("lena_sobel.raw", "wb");
    fwrite(res, sizeof(unsigned char), WIDTH * HEIGHT, fp);
    fclose(fp);

    return 0;
}

这个示例代码读取一张名为lena.raw的灰度图像，使用Sobel算子进行边缘检测，最终将结果图像保存为lena_sobel.raw。