通过函数调用使用pyrdown

Question

我试图用pyrDown()来缩小所需的图像。为此我使用了一个函数调用void downscale(Mat *p,int *scale)。我发送了ref到图像的函数。因此，在函数完成了下采样我的原始图像的图像会发生改变，因为我发送了指针。图像在函数调用中得到缩放。但令我惊讶的是主程序中的图像没有变化。我不明白我出错的地方。出我的错误？ 这里是我的代码

#include <opencv2/core/core.hpp> 
 
#include<opencv2/opencv.hpp> 
 
#include<opencv2/imgproc/imgproc.hpp> 
 
#include<stdio.h> 
 
#include<conio.h> 
 
#include<opencv2/highgui/highgui.hpp> 
 
#include<opencv2/objdetect/objdetect.hpp> 
 
#include<opencv2/features2d/features2d.hpp> 
 
#include<opencv2/nonfree/nonfree.hpp> 
 

 
using namespace std; 
 
using namespace cv; 
 

 
void downscale(Mat *p,int scale) 
 
{ 
 
\t int s=scale; 
 

 
\t Mat ref=*p; 
 
\t 
 
\t imshow("received",ref); 
 
\t vector<int> param; 
 
\t param.push_back(CV_IMWRITE_PNG_COMPRESSION) ; 
 
\t param.push_back(9); 
 

 
\t while(s){ 
 
\t pyrDown(ref,ref,Size(),4); 
 
\t s--; 
 
\t } 
 
\t imshow("sending",ref); 
 
} 
 

 

 

 
int main() 
 
{ 
 
\t Mat ref,in,ref_out,in_out; 
 
\t int s=2; 
 
\t ref=imread("C:\\Users\\vamsidhar muthireddy\\Pictures\\Camera Roll\\WIN_20151003_18_47_55_Pro.jpg"); 
 

 
\t cvtColor(ref,ref,CV_BGR2GRAY); 
 

 
\t 
 

 
\t imshow("original ref",ref); 
 
\t downscale(&ref,s); 
 

 
\t imshow("scaled ref",ref); 
 

 
    waitKey(); 
 
\t return 0; 
 
}

Answer 1

变化缩减到：

void downscale(Mat &ref,int scale) 
{ 
int s=scale; 

imshow("received",ref); 
vector<int> param; 
param.push_back(CV_IMWRITE_PNG_COMPRESSION) ; 
param.push_back(9); 

while(s){ 
pyrDown(ref,ref,Size(),4); 
s--; 
} 
imshow("sending",ref); 

，并称呼其为：

downscale(ref,s);