medianBlur(InputArray src,OutputArray dst,int ksize);

 1 //load the Original Image and get some informations2 Mat src = imread("010.jpg",1);3 namedWindow("OriginalImage");4 imshow("OriginalImage",src);5 CV_Assert(src.depth() == CV_8U);6 const int nr = src.rows;7 const int nc = src.cols;8 const int nchannels = src.channels();9
10 //OpenCV Solution
11 Mat result_opencv;
12 medianBlur(src,result_opencv,3);
13 namedWindow("median filter_opencv");
14 imshow("median filter_opencv",result_opencv);

 1 //own median filter algorithm2 uchar* previous = NULL;3 uchar* current = NULL;4 uchar* next = NULL;5 uchar* current_result_own = NULL;6 int arr[9];   //use 3*3 mask7 for(int i=1;i<nr-1;i++)8 {9     previous = src.ptr<uchar>(i-1);
10     current = src.ptr<uchar>(i);
11     next = src.ptr<uchar>(i+1);
12     current_result_own = result_own.ptr<uchar>(i);
13     for(int j=nchannels;j<nchannels*(nc-1);j++)
14     {
15         for(int k=0;k<3;k++)
16         {
17             arr[k] = previous[j+(k-1)*nchannels];
18             arr[k+3] = current[j+(k-1)*nchannels];
19             arr[k+6] = next[j+(k-1)*nchannels];
20         }
21         bubble_sort(arr,9);
22         current_result_own[j] = arr[4];
23     }
24 }
25
26 //set the pixels on the borders to zeros
27 result_own.row(0).setTo(Scalar(0));
28 result_own.row(nr-1).setTo(Scalar(0));
29 result_own.col(0).setTo(Scalar(0));
30 result_own.col(nc-1).setTo(Scalar(0));
31
32 //show the result
33 namedWindow("median filter_own");
34 imshow("median filter_own",result_own);

 1 //************************//2 //bubble sort3 //************************//4 void bubble_sort(int* arr,int num)5 {6     int temp;7     for(int i=1;i<num-1;i++)8     {9         for(int j=0;j<num-i;j++)
10            {
11                if(arr[j]>arr[j+1])
12                {
13                    temp = arr[j];
14                    arr[j] = arr[j+1];
15                    arr[j+1] = temp;
16                }
17            }
18     }
19 }