c语言实现图像中值滤波去噪

以下是使用C语言实现图像中值滤波的示例代码：

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

#define WIDTH 512
#define HEIGHT 512

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

    // 中值滤波
    unsigned char* res = (unsigned char*)malloc(sizeof(unsigned char) * WIDTH * HEIGHT);
    int window_size = 3; // 窗口大小
    int half_win = window_size / 2;
    int* values = (int*)malloc(sizeof(int) * window_size * window_size);
    int index = 0;
    for (int i = half_win; i < HEIGHT - half_win; i++) {
        for (int j = half_win; j < WIDTH - half_win; j++) {
            index = 0;
            for (int k = -half_win; k <= half_win; k++) {
                for (int l = -half_win; l <= half_win; l++) {
                    *(values + index) = *(img + (i + k) * WIDTH + (j + l));
                    index++;
                }
            }
            // 对窗口内像素值进行排序
            for (int k = 0; k < window_size * window_size - 1; k++) {
                for (int l = k + 1; l < window_size * window_size; l++) {
                    if (*(values + l) < *(values + k)) {
                        int tmp = *(values + k);
                        *(values + k) = *(values + l);
                        *(values + l) = tmp;
                    }
                }
            }
            // 取中值并保存
            *(res + i * WIDTH + j) = (unsigned char)*(values + window_size * window_size / 2);
        }
    }

    // 输出图像
    fp = fopen("lena_median.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_noise.raw的灰度图像，使用中值滤波进行去噪，最终将结果图像保存为lena_median.raw。在中值滤波中，我们使用一个窗口对每个像素进行处理，将窗口内的像素值进行排序，取中值作为该像素的新值。窗口大小可以根据实际需要进行调整。