用c语言编写图像二极化代码

以下是一个简单的用 C 语言编写的图像二极化代码：

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

#define THRESHOLD 128

int main(int argc, char *argv[]) {
    if (argc != 3) {
        printf("Usage: %s input_file output_file\n", argv[0]);
        return 1;
    }

    FILE *input_file = fopen(argv[1], "rb");
    if (!input_file) {
        printf("Failed to open input file: %s\n", argv[1]);
        return 1;
    }

    FILE *output_file = fopen(argv[2], "wb");
    if (!output_file) {
        printf("Failed to open output file: %s\n", argv[2]);
        fclose(input_file);
        return 1;
    }

    unsigned char header[54];
    fread(header, sizeof(unsigned char), 54, input_file);
    fwrite(header, sizeof(unsigned char), 54, output_file);

    int width = *(int *)&header[18];
    int height = *(int *)&header[22];
    int padding = (4 - (width * 3) % 4) % 4;

    unsigned char pixel[3];
    for (int y = 0; y < height; y++) {
        for (int x = 0; x < width; x++) {
            fread(pixel, sizeof(unsigned char), 3, input_file);
            unsigned char gray = (pixel[0] + pixel[1] + pixel[2]) / 3;
            if (gray >= THRESHOLD) {
                pixel[0] = 255;
                pixel[1] = 255;
                pixel[2] = 255;
            } else {
                pixel[0] = 0;
                pixel[1] = 0;
                pixel[2] = 0;
            }
            fwrite(pixel, sizeof(unsigned char), 3, output_file);
        }
        fseek(input_file, padding, SEEK_CUR);
        for (int i = 0; i < padding; i++) {
            fputc(0, output_file);
        }
    }

    fclose(input_file);
    fclose(output_file);
    return 0;
}

这个程序可以读取一个 BMP 格式的图像文件，将其转换为黑白二值图像，并输出到另一个文件中。具体的实现方式是，对于每个像素，计算其 RGB 值的平均值，如果大于等于阈值 THRESHOLD，则将其设为白色，否则设为黑色。