Filter2D 滤波

叁歲伎倆 2022-04-02 16:44 276阅读 0赞

## correlation with kernel ##

*  核在图像上扫描的结果，公式：

![20181227134018499.png][]

I I I是输入图像， K K K是核， M i M j M\_i M\_j MiMj是核的大小， a i a j a\_i a\_j aiaj是anchor

--------------------

## 代码 ##

#include <opencv2/opencv.hpp>
    #include <iostream>
    
    using namespace cv;
    using namespace std;
    
    
    
    int main(void)
    { 
    	
    	Mat src,dst;
    	Mat kernel;
    
    	const char* window_name = "Filter2D Demo";
    	const char* image_name = "../res/beauty.jpg";
    
    	src = imread(image_name,cv::IMREAD_COLOR);
    	if(src.empty())
    	{ 
    		cout << " can't load image" << endl;
    	}
    
    	Point anchor(-1,-1); //中间的点
    	int depth = -1 ;//深度和输入一样
    	int delta = 0; //在处理之后　再加上delta,默认0
    
    
    	int kernel_size = 0;
    	int ind = 0;
    
    	for(;;)
    	{ 
    		kernel_size = 3 + 2*(ind%5);  // 3 5 7 9 11
    		kernel = Mat::ones(kernel_size,kernel_size,CV_32F)/(float)(kernel_size*kernel_size);//均值滤波的核
    		filter2D(src,dst,depth,kernel,anchor,delta);
    		imshow(window_name,dst);
    
    		
    		char c = (char)waitKey(500);//每500ms 
    		if(c==27)
    			break;
    		ind++;
    	}
    
    	return 0;
    };

结果：

原图 ![20181227141115187.png][]![20181227143323521.png][]

--------------------

## OpenCV API ##

**自己创建核，利用此函数进行correlation，具体作用取决于核**

void cv::filter2D  
(  
InputArray src,  
OutputArray dst,  
int ddepth,      // 输出图像的深度，-1/CV\_16S/CV\_32F/CV\_64F ，-1代表和输入图像一样  
InputArray kernel,  
Point anchor = Point(-1,-1),  
double delta = 0,     // correlation之后 每个像素再加上这个值  
int borderType = BORDER\_DEFAULT  
)

[20181227134018499.png]: /images/20220402/e988be73a6d74e5cb067dc91b4f8c57c.png
[20181227141115187.png]: https://img-blog.csdnimg.cn/20181227141115187.png
[20181227143323521.png]: /images/20220402/3174d5430d4c4c589bd733048a5197a9.png