C语言模板匹配程序，不依赖第三方库

如果你不想依赖第三方库，你可以使用C语言的图像处理库，如stb_image和stb_image_write，来实现模板匹配。下面是一个简单的C语言模板匹配程序示例：

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

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"

int main()
{
    // Load source and template images
    int src_width, src_height, src_channels;
    unsigned char *src_data = stbi_load("source.jpg", &src_width, &src_height, &src_channels, 0);

    int tpl_width, tpl_height, tpl_channels;
    unsigned char *tpl_data = stbi_load("template.jpg", &tpl_width, &tpl_height, &tpl_channels, 0);

    // Convert source and template images to grayscale
    unsigned char *src_gray = (unsigned char *)malloc(src_width * src_height);
    unsigned char *tpl_gray = (unsigned char *)malloc(tpl_width * tpl_height);

    for (int i = 0; i < src_width * src_height; i++) {
        int r = src_data[i * src_channels];
        int g = src_data[i * src_channels + 1];
        int b = src_data[i * src_channels + 2];
        src_gray[i] = (unsigned char)(0.299 * r + 0.587 * g + 0.114 * b);
    }

    for (int i = 0; i < tpl_width * tpl_height; i++) {
        int r = tpl_data[i * tpl_channels];
        int g = tpl_data[i * tpl_channels + 1];
        int b = tpl_data[i * tpl_channels + 2];
        tpl_gray[i] = (unsigned char)(0.299 * r + 0.587 * g + 0.114 * b);
    }

    // Compute correlation between source and template images
    int result_width = src_width - tpl_width + 1;
    int result_height = src_height - tpl_height + 1;
    float *result_data = (float *)malloc(result_width * result_height * sizeof(float));

    for (int y = 0; y < result_height; y++) {
        for (int x = 0; x < result_width; x++) {
            float sum = 0.0f;
            for (int j = 0; j < tpl_height; j++) {
                for (int i = 0; i < tpl_width; i++) {
                    int src_x = x + i;
                    int src_y = y + j;
                    int tpl_x = i;
                    int tpl_y = j;
                    unsigned char src_pixel = src_gray[src_y * src_width + src_x];
                    unsigned char tpl_pixel = tpl_gray[tpl_y * tpl_width + tpl_x];
                    sum += (float)src_pixel * (float)tpl_pixel;
                }
            }
            result_data[y * result_width + x] = sum;
        }
    }

    // Find maximum correlation value and corresponding position
    float max_val = result_data[0];
    int max_x = 0, max_y = 0;

    for (int y = 0; y < result_height; y++) {
        for (int x = 0; x < result_width; x++) {
            float val = result_data[y * result_width + x];
            if (val > max_val) {
                max_val = val;
                max_x = x;
                max_y = y;
            }
        }
    }

    // Draw rectangle around matched region in source image
    for (int y = 0; y < src_height; y++) {
        for (int x = 0; x < src_width; x++) {
            if (x >= max_x && x < max_x + tpl_width && y >= max_y && y < max_y + tpl_height) {
                src_data[(y * src_width + x) * src_channels] = 0;
                src_data[(y * src_width + x) * src_channels + 1] = 0;
                src_data[(y * src_width + x) * src_channels + 2] = 255;
            }
        }
    }

    // Save marked source image
    stbi_write_jpg("result.jpg", src_width, src_height, src_channels, src_data, 100);

    // Free memory
    stbi_image_free(src_data);
    stbi_image_free(tpl_data);
    free(src_gray);
    free(tpl_gray);
    free(result_data);

    return 0;
}

上面的程序将原始图像和模板图像加载到内存中，将它们转换为灰度图像，并执行模板匹配，查找匹配位置，并在原始图像上标记匹配位置。最后，它将保存标记后的原始图像。