C++ OpenCV 把一张图藏到另外一张图中（图像加水印）

逃离我推掉我的手 2024-04-17 05:55 51阅读 0赞

图像的像素值的范围为\[0,255\],8位2进制表示\[00000000,11111111\]

uchar 无符号8位2进制。

采用截取图像A的最后2位（2位只能表示4种可能性），用于藏图像B。涉及到C++的位操作:  >>  ,<< , &  , | 四种操作即可。

此时的图像，有2点要求：1、被藏图像B（水印图像）较单调，像素值较集中。2、图像B尽可能保持与图像A相同尺寸。3、图像A和B竟然采用无压缩格式储存图像格式（BMP格式），其他比如JPG格式是有损压缩。

# 图像A,下图: #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70][]

# 图像B,下图: #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 1][]

#include <opencv2/opencv.hpp>
    #include <opencv2/core/core.hpp>
    #include<opencv2/imgproc/imgproc.hpp>
    #include <opencv2/highgui/highgui.hpp>
    #include <iostream>
    #include <queue>
    using namespace std;
    using namespace cv;
    
    
    void pic_add(Mat &image, Mat &image_water)
    {
    	cout << image.rows << " " << image.cols << " " << image.channels() << " " << image.type() << " " << endl;
    	cout << "image.channels() = " << image.channels() << endl;
    	//cout << image_water.rows << " " << image_water.cols << " " << image_water.dims << endl;
    	int nr = image.rows; // number of rows
    	int nc = image.cols; // number of columns
    	for (int j = 0; j < nr; j++)
    	{
    		for (int i = 0; i < nc; i++)
    		{
    			uchar a = 0xfc;
    			uchar thes = 50;
    			image.at<Vec3b>(j, i)[0] = image.at<Vec3b>(j, i)[0] & a;
    			image.at<Vec3b>(j, i)[1] = image.at<Vec3b>(j, i)[1] & a;
    			image.at<Vec3b>(j, i)[2] = image.at<Vec3b>(j, i)[2] & a;
    
    			Vec3b p;
    			
    			p[0] = image_water.at<Vec3b>(j, i)[0] >> 6;
    			p[1] = image_water.at<Vec3b>(j, i)[1] >> 6;
    			p[2] = image_water.at<Vec3b>(j, i)[2] >> 6;
    			
    			image.at<Vec3b>(j, i)[0] = image.at<Vec3b>(j, i)[0] | p[0];
    			image.at<Vec3b>(j, i)[1] = image.at<Vec3b>(j, i)[1] | p[1];
    			image.at<Vec3b>(j, i)[2] = image.at<Vec3b>(j, i)[2] | p[2];
    
    		}
    	}
    
    	imwrite("C:\\Users\\kai\\Pictures\\test\\tiqu_20190824re111111.bmp", image);
    	cv::namedWindow("Original Water add Image");
    	cv::imshow("Original Water add Image", image);
    }
    
    
    int main()
    {
    	String path = "C:\\Users\\kai\\Pictures\\test\\1.bmp";
    	String pathadd = "C:\\Users\\kai\\Pictures\\test\\2.bmp";
    
    	cv::Mat image = cv::imread(path, 1);  //1.bmp
    	cv::Mat image_water = cv::imread("C:\\Users\\kai\\Pictures\\test\\2.bmp", 1);
    	/*载入标识，指定一个加载图像的颜色类型，
    	默认值为1，表示载入三通道的彩色图像；
    			-1，imread按解码得到的方式读入图像；
    		    0，imread按单通道的方式读入图像，即灰白图像。*/
    	if (!image.data)	return 0;
    	Mat drawing = Mat::zeros(image.size(), CV_8UC3);//初始化一个背景为黑色矩阵
    
    	pic_add(image, image_water);
    
    	cout << image.rows << " " << image.cols << " " << image.channels() << " " << image.type() << " " << endl;
    	cout << "image.channels() = " << image.channels()  << endl;
    
    	cv::namedWindow("Original Image");
    	cv::imshow("Original Image", image);
    
    	cv::namedWindow("Original Water Image");
    	cv::imshow("Original Water Image", image_water);
    	
    	waitKey(0);
    	return 0;
    }

# 对比图像（左边是原图，右边是要加入的水印图像） #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 2][]

# 对比图像（左边是原图，右边是加了水印的图像），看不出差别。 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 3][]

提取水印图像，只需要提取加了水印的图像C的像素值最后2位即可。

#include <opencv2/opencv.hpp>
    #include <opencv2/core/core.hpp>
    #include<opencv2/imgproc/imgproc.hpp>
    #include <opencv2/highgui/highgui.hpp>
    #include <iostream>
    #include <queue>
    using namespace std;
    using namespace cv;
    
    void extract(Mat &image)
    {
    	Mat drawing = Mat::zeros(image.size(), CV_8UC3);//初始化一个背景为黑色矩阵
    
    	int nr = image.rows; // number of rows
    	int nc = image.cols; // number of columns
    	for (int j = 0; j < nr; j++)
    	{
    		for (int i = 0; i < nc; i++)
    		{
    			uchar a = 0x03;
    			uchar b = 0xff;
    			uchar c = 0xc0;
    			drawing.at<Vec3b>(j, i)[0] = image.at<Vec3b>(j, i)[0] & a;
    			drawing.at<Vec3b>(j, i)[1] = image.at<Vec3b>(j, i)[1] & a;
    			drawing.at<Vec3b>(j, i)[2] = image.at<Vec3b>(j, i)[2] & a;
    			//cout << drawing.at<Vec3b>(j, i) << " ";
    			
    			drawing.at<Vec3b>(j, i)[0] = drawing.at<Vec3b>(j, i)[0] << 6;
    			drawing.at<Vec3b>(j, i)[1] = drawing.at<Vec3b>(j, i)[1] << 6;
    			drawing.at<Vec3b>(j, i)[2] = drawing.at<Vec3b>(j, i)[2] << 6;
    
    			if (drawing.at<Vec3b>(j, i)[0] ==  c )
    				drawing.at<Vec3b>(j, i)[0] = 255;
    			if (drawing.at<Vec3b>(j, i)[1] ==  c )
    				drawing.at<Vec3b>(j, i)[1] = 255;
    			if (drawing.at<Vec3b>(j, i)[2] ==  c )
    				drawing.at<Vec3b>(j, i)[2] = 255;
    		}
    	}
    	imwrite("C:\\Users\\kai\\Pictures\\test\\tiqu_20190824.bmp", drawing);
    	//cvSaveImage("gray_mat.jgp", binaryAdaptive); tiqu_20190823.jpg
    	cv::namedWindow("Original Water extract Image");
    	cv::imshow("Original Water extract Image", drawing);
    }
    
    int main()
    {
    
    	String result_path = "C:\\Users\\kai\\Pictures\\test\\result.bmp";
    	cv::Mat result_img = cv::imread(result_path, 1);
    	/*载入标识，指定一个加载图像的颜色类型，
    	默认值为1，表示载入三通道的彩色图像；
    			-1，imread按解码得到的方式读入图像；
    		    0，imread按单通道的方式读入图像，即灰白图像。*/
    	if (!image.data)	return 0;
    
    	// display original image  
    	cv::namedWindow("Original Image");
    	cv::imshow("Original Image", result_img);
    
    	cv::namedWindow("Original Water Image");
    	cv::imshow("Original Water Image", image_water);
    	
    	extract(result_img);
    
    	cout << image.rows << " " << image.cols << " " << image.channels() << " " << image.type() << " " << endl;
    	cout << "image.channels() = " << image.channels()  << endl;
    	
    	waitKey(0);
    	return 0;
    }

# 对比图像（左边是加了水印的图像，右边是提取的水印图像）。![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 4][] #

# 对比图像（左边是提取的水印图像，右边是原始的水印图像）。两者基本一致，红箭头标注的角落上还有点细微差别。 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 5][]

# 本方法加水印的方法抗噪能力不行，一旦图像有发生——图像像素值变化会导致水印提取结果很差。 #

# 直方图均值化后，水印提取的结果： #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 6][]

# 加了水印的图像以JPG格式保存，有损压缩导致像素值恢复时候发生变动，导致噪声很大。 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 7][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20190824232315181.bmp?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/2019082423235024.bmp?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/7b07fbd3c42849d6b62762e16dc11ce1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 3]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/411e494f15494a89b538553dc38094d8.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 4]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/3ebc1f5a1015447a82f7b892fb3010d3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 5]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/bfb1a44b702046c29b6dc4c337b888c1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 6]: https://img-blog.csdnimg.cn/20190824235322590.bmp?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ_size_16_color_FFFFFF_t_70 7]: https://img-blog.csdnimg.cn/20190825000303443.bmp?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1a2FpMDkwOQ==,size_16,color_FFFFFF,t_70