【opencv-c++】矩阵的掩膜操作

柔情只为你懂 2022-02-22 21:04 288阅读 0赞

图像的掩膜操作可以提高图像的对比度，这里需要用到的知识点

（0）如何创建一个Mat对象

（1）获取图像像素的指针

获得当前行指针const uchar\*  current= myImage.ptr<uchar>(row );

（2）像素范围处理

saturate\_cast<uchar>（）

（3）掩膜操作

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BsU29uZ19DU0RO_size_16_color_FFFFFF_t_70][]

参考代码

#include<iostream>
    #include<opencv2\opencv.hpp>
    
    using namespace cv;
    using namespace std;
    
    int main()
    {
    	//load image
    	Mat src = imread("D:/opencv3.1.0/images/test.png");
    	if (src.empty())
    	{
    		cout << "image load error" << endl;
    		return -1;
    	}
    	imshow("input image win", src);
    
    	//define some paraments
    	int cols = (src.cols - 1)*src.channels();
    	int rows = src.rows;
    	int offsex = src.channels();
    
    	//main opertion
    	Mat dst = Mat::zeros(src.size(), src.type()); //creat a Mat with the same size and type as src,
    	for (int row = 1; row < (rows - 1); row++)
    	{
    		
    		const uchar* previous = src.ptr<uchar>(row - 1);
    		const uchar* current = src.ptr<uchar>(row);//gey current rows pointer
    		const uchar* next = src.ptr<uchar>(row + 1);
    
    		uchar* output = dst.ptr<uchar>(row);
    
    		for (int col = offsex; col < cols; col++)
    		{
    			//saturate_cast<uchar>( )//ensure the number betweent 0-255
    			output[col] = saturate_cast<uchar>(5 * current[col] - (current[col - offsex] + current[col + offsex] + previous[col] + next[col]));
    		}
    	}
    
    	imshow("result win", dst);
    	waitKey(0);
    	return 0;
    
    }

运行效果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BsU29uZ19DU0RO_size_16_color_FFFFFF_t_70 1][]

还可以是opencv的内置函数

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BsU29uZ19DU0RO_size_16_color_FFFFFF_t_70]: /images/20220223/712b2fa21b2c4fa68ffc4e5334c3a2cb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BsU29uZ19DU0RO_size_16_color_FFFFFF_t_70 1]: /images/20220223/2145e8a1f2cd47a888f9e5007467f7e8.png