数字水印dct代码csdn

以下是使用DCT（离散余弦变换）实现数字水印嵌入和提取的示例代码。该代码使用C语言编写，并使用OpenCV库。具体实现方法如下：

首先，我们需要将图像转换为灰度图像，然后使用DCT变换对其进行转换。然后，我们将水印图像嵌入到低频区域中，通过更改其中的DCT系数来实现。在提取水印时，我们需要再次对图像进行DCT变换，并提取嵌入的DCT系数，然后使用相同的方法提取水印图像。

嵌入数字水印的代码如下：

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
using namespace std;

// 定义水印大小（以像素为单位）
#define WATERMARK_SIZE 32

// 定义水印强度
#define ALPHA 0.005

// 定义图像转换为DCT系数的函数
void convertImageToDct(Mat& image, Mat& dct) {
    dct.convertTo(dct, CV_32F);
    dct = Mat::zeros(dct.size(), CV_32F);
    for (int i = 0; i < image.rows; i += 8) {
        for (int j = 0; j < image.cols; j += 8) {
            Mat block = image(Rect(j, i, 8, 8));
            dct.at<float>(i, j) = block.at<uchar>(0, 0);
            dct.at<float>(i + 1, j) = block.at<uchar>(0, 1);
            dct.at<float>(i + 2, j) = block.at<uchar>(0, 2);
            dct.at<float>(i + 3, j) = block.at<uchar>(0, 3);
            dct.at<float>(i + 4, j) = block.at<uchar>(0, 4);
            dct.at<float>(i + 5, j) = block.at<uchar>(0, 5);
            dct.at<float>(i + 6, j) = block.at<uchar>(0, 6);
            dct.at<float>(i + 7, j) = block.at<uchar>(0, 7);
            dct.at<float>(i, j + 1) = block.at<uchar>(1, 0);
            dct.at<float>(i + 1, j + 1) = block.at<uchar>(1, 1);
            dct.at<float>(i + 2, j + 1) = block.at<uchar>(1, 2);
            dct.at<float>(i + 3, j + 1) = block.at<uchar>(1, 3);
            dct.at<float>(i + 4, j + 1) = block.at<uchar>(1, 4);
            dct.at<float>(i + 5, j + 1) = block.at<uchar>(1, 5);
            dct.at<float>(i + 6, j + 1) = block.at<uchar>(1, 6);
            dct.at<float>(i + 7, j + 1) = block.at<uchar>(1, 7);
            dct.at<float>(i, j + 2) = block.at<uchar>(2, 0);
            dct.at<float>(i + 1, j + 2) = block.at<uchar>(2, 1);
            dct.at<float>(i + 2, j + 2) = block.at<uchar>(2, 2);
            dct.at<float>(i + 3, j + 2) = block.at<uchar>(2, 3);
            dct.at<float>(i + 4, j + 2) = block.at<uchar>(2, 4);
            dct.at<float>(i + 5, j + 2) = block.at<uchar>(2, 5);
            dct.at<float>(i + 6, j + 2) = block.at<uchar>(2, 6);
            dct.at<float>(i + 7, j + 2) = block.at<uchar>(2, 7);
            dct.at<float>(i, j + 3) = block.at<uchar>(3, 0);
            dct.at<float>(i + 1, j + 3) = block.at<uchar>(3, 1);
            dct.at<float>(i + 2, j + 3) = block.at<uchar>(3, 2);
            dct.at<float>(i + 3, j + 3) = block.at<uchar>(3, 3);
            dct.at<float>(i + 4, j + 3) = block.at<uchar>(3, 4);
            dct.at<float>(i + 5, j + 3) = block.at<uchar>(3, 5);
            dct.at<float>(i + 6, j + 3) = block.at<uchar>(3, 6);
            dct.at<float>(i + 7, j + 3) = block.at<uchar>(3, 7);
            dct.at<float>(i, j + 4) = block.at<uchar>(4, 0);
            dct.at<float>(i + 1, j + 4) = block.at<uchar>(4, 1);
            dct.at<float>(i + 2, j + 4) = block.at<uchar>(4, 2);
            dct.at<float>(i + 3, j + 4) = block.at<uchar>(4, 3);
            dct.at<float>(i + 4, j + 4) = block.at<uchar>(4, 4);
            dct.at<float>(i + 5, j + 4) = block.at<uchar>(4, 5);
            dct.at<float>(i + 6, j + 4) = block.at<uchar>(4, 6);
            dct.at<float>(i + 7, j + 4) = block.at<uchar>(4, 7);
            dct.at<float>(i, j + 5) = block.at<uchar>(5, 0);
            dct.at<float>(i + 1, j + 5) = block.at<uchar>(5, 1);
            dct.at<float>(i + 2, j + 5) = block.at<uchar>(5, 2);
            dct.at<float>(i + 3, j + 5) = block.at<uchar>(5, 3);
            dct.at<float>(i + 4, j + 5) = block.at<uchar>(5, 4);
            dct.at<float>(i + 5, j + 5) = block.at<uchar>(5, 5);
            dct.at<float>(i + 6, j + 5) = block.at<uchar>(5, 6);
            dct.at<float>(i + 7, j + 5) = block.at<uchar>(5, 7);
            dct.at<float>(i, j + 6) = block.at<uchar>(6, 0);
            dct.at<float>(i + 1, j + 6) = block.at<uchar>(6, 1);
            dct.at<float>(i + 2, j + 6) = block.at<uchar>(6, 2);
            dct.at<float>(i + 3, j + 6) = block.at<uchar>(6, 3);
            dct.at<float>(i + 4, j + 6) = block.at<uchar>(6, 4);
            dct.at<float>(i + 5, j + 6) = block.at<uchar>(6, 5);
            dct.at<float>(i + 6, j + 6) = block.at<uchar>(6, 6);
            dct.at<float>(i + 7, j + 6) = block.at<uchar>(6, 7);
            dct.at<float>(i, j + 7) = block.at<uchar>(7, 0);
            dct.at<float>(i + 1, j + 7) = block.at<uchar>(7, 1);
            dct.at<float>(i + 2, j + 7) = block.at<uchar>(7, 2);
            dct.at<float>(i + 3, j + 7) = block.at<uchar>(7, 3);
            dct.at<float>(i + 4, j + 7) = block.at<uchar>(7, 4);
            dct.at<float>(i + 5, j + 7) = block.at<uchar>(7, 5);
            dct.at<float>(i + 6, j + 7) = block.at<uchar>(7, 6);
            dct.at<float>(i + 7, j + 7) = block.at<uchar>(7, 7);
            dct.at<float>(i, j) -= 128;
            dct.at<float>(i + 1, j) -= 128;
            dct.at<float>(i + 2, j) -= 128;
            dct.at<float>(i + 3, j) -= 128;
            dct.at<float>(i + 4, j) -= 128;
            dct.at<float>(i + 5, j) -= 128;
            dct.at<float>(i + 6, j) -= 128;
            dct.at<float>(i + 7, j) -= 128;
            dct.at<float>(i, j + 1) -= 128;
            dct.at<float>(i + 1, j + 1) -= 128;
            dct.at<float>(i + 2, j + 1) -= 128;
            dct.at<float>(i + 3, j + 1) -= 128;
            dct.at<float>(i + 4, j + 1) -= 128;
            dct.at<float>(i + 5, j + 1) -= 128;
            dct.at<float>(i + 6, j + 1) -= 128;
            dct.at<float>(i + 7, j + 1) -= 128;
            dct.at<float>(i, j + 2) -= 128;
            dct.at<float>(i + 1, j + 2) -= 128;
            dct.at<float>(i + 2, j + 2) -= 128;
            dct.at<float>(i + 3, j + 2) -= 128;
            dct.at<float>(i + 4, j + 2) -= 128;
            dct.at<float>(i + 5, j + 2) -= 128;
            dct.at<float>(i + 6, j + 2) -= 128;
            dct.at<float>(i + 7, j + 2) -= 128;
            dct.at<float>(i, j + 3) -= 128;
            dct.at<float>(i + 1, j + 3) -= 128;
            dct.at<float>(i + 2, j + 3) -= 128;
            dct.at<float>(i + 3, j + 3) -= 128;
            dct.at<float>(i + 4, j + 3) -= 128;
            dct.at<float>(i + 5, j + 3) -= 128;
            dct.at<float>(i + 6, j + 3) -= 128;
            dct.at<float>(i + 7, j + 3) -= 128;
            dct.at<float>(i, j + 4) -= 128;
            dct.at<float>(i + 1, j + 4) -= 128;
            dct.at<float>(i + 2, j + 4) -= 128;
            dct.at<float>(i + 3, j + 4) -= 128;
            dct.at<float>(i + 4, j + 4) -= 128;
            dct.at<float>(i + 5, j + 4) -= 128;
            dct.at<float>(i + 6, j + 4) -= 128;
            dct.at<float>(i + 7, j + 4) -= 128;
            dct.at<float>(i, j + 5) -= 128;
            dct.at<float>(i + 1, j + 5) -= 128;
            dct.at<float>(i + 2, j + 5) -= 128;
            dct.at<float>(i + 3, j + 5) -= 128;
            dct.at<float>(i + 4, j + 5) -= 128;
            dct.at<float>(i + 5, j + 5) -= 128;
            dct.at<float>(i + 6, j + 5) -= 128;
            dct.at<float>(i + 7, j + 5) -= 128;
            dct.at<float>(i, j + 6) -= 128;
            dct.at<float>(i + 1, j + 6) -= 128;
            dct.at<float>(i + 2, j + 6) -= 128;
            dct.at<float>(i + 3, j + 6) -= 128;
            dct.at<float>(i + 4, j + 6) -= 128;
            dct.at<float>(i + 5, j + 6) -= 128;
            dct.at<float>(i + 6, j + 6) -= 128;
            dct.at<float>(i + 7, j + 6) -= 128;
            dct.at<float>(i, j + 7) -= 128;
            dct.at<float>(i + 1, j + 7) -= 128;
            dct.at<float>(i + 2, j + 7) -= 128;
            dct.at<float>(i + 3, j + 7) -= 128;
            dct.at<float>(i + 4, j + 7) -= 128;
            dct.at<float>(i + 5, j + 7) -= 128;
            dct.at<float>(i + 6, j + 7) -= 128;
            dct.at<float>(i + 7, j + 7) -= 128;
            dct.at<float>(i, j) /= sqrt(64.0);
            dct.at<float>(i + 1, j) /= sqrt(64.0);
            dct.at<float>(i + 2, j) /= sqrt(64.0);
            dct.at<float>(i + 3, j) /= sqrt(64.0);
            dct.at<float>(i + 4, j) /= sqrt(64.0);
            dct.at<float>(i + 5, j) /= sqrt(64.0);
            dct.at<float>(i + 6, j) /= sqrt(64.0);
            dct.at<float>(i + 7, j) /= sqrt(64.0);
            dct.at<float>(i, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 1, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 2, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 3, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 4, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 5, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 6, j + 1) /= sqrt(64.0);
            dct.at<float>(i + 7, j + 1) /= sqrt(64.0);
            dct.at<float>(i, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 1, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 2, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 3, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 4, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 5, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 6, j + 2) /= sqrt(64.0);
            dct.at<float>(i + 7, j + 2) /= sqrt(64.0);
            dct.at<float>(i, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 1, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 2, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 3, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 4, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 5, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 6, j + 3) /= sqrt(64.0);
            dct.at<float>(i + 7, j + 3) /= sqrt(64.0);
            dct.at<float>(i, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 1, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 2, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 3, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 4, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 5, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 6, j + 4) /= sqrt(64.0);
            dct.at<float>(i + 7, j + 4) /= sqrt(64.0);
            dct.at<float>(i, j + 5) /= sqrt(64.0);
            dct.at<float>(i + 1, j + 5) /= sqrt(64.0