High-efficiency mean filtering (using Copymakeborder to process boundary pixels)

The previous filtering algorithm is modified, and the Copymakeborder expansion boundary pixels are adopted, which brings great convenience to the processing of boundary pixels.

<span style= "FONT-SIZE:14PX;" >void Blur (const Mat &IMAGE_SRC, Mat &image_dst, Size size_aperture) {/////////////////////////////step 1. Reassign the image (if needed)///////////////////////////////////////////////the size of the new image int Width_dst=image_src.cols;int height_Dst= Image_src.rows;image_dst.create (Size (WIDTH_DST,HEIGHT_DST), CV_8UC1);//If reassigned, the previous space is discarded///////////////////////// Step 2. Create a new image (expand the source image)//////////////////////////////////////////////expanded size int width_extend=size_ Aperture.width>>1;int height_extend=size_aperture.height>>1;//Create a new image </span>

<span style= "FONT-SIZE:14PX;" ><span style= "White-space:pre" ></span>//here with OpenCV in the same way Border_defaultmat image_new; Copymakeborder (Image_src,image_new,height_extend,height_extend,width_extend,width_extend,border_default);///// Step 3. Filter////////////////////////////////////////////////new Image parameter int Width_new=image_ New.cols;int height_new=image_new.rows;int widthstep_new=width_new;//sliding window int width_aperture=size_aperture.width; int Height_aperture=size_aperture.height;int pixelcount=width_aperture*height_aperture;//calculates the starting coordinate int startX= of the filtered pixels Width_aperture>>1;int starty=height_aperture>>1;//Each column's grayscale value and int *sum_percol=new int[width_New];// Filtering the new image Uchar *row_new=image_new.data+starty*widthstep_new+startx;uchar *row_dst=image_dst.data;//first row Uchar *row_ aperture_new=image_new.data;for (int y=starty;y<=height_new-starty-1;++y) {//column Uchar *col_dst=row_dst;uchar *col_ aperture_new=row_aperture_new;//calculates the grayscale value of height_aperture pixels per column and//First row, calculates all columns and if (Y==starty) {for (int K=0;k<=width_new-1;++k) {sum_percol[k]=0;//The first pointer of each column UCHAR *col_perline=col_aperture_new+k;for (int t=0;t<= Height_aperture-1;++t) {sum_percol[k]+=col_perline[0];col_perline+=widthstep_new;//The next line}}}else//not the first line {for (int k=0; K&LT;=WIDTH_NEW-1;++K) {//The first pointer of each column Uchar *col_=col_aperture_new+k;sum_percol[k]-=col_[0-widthstep_new];//minus the top sum_ percol[k]+=col_[0+ (height_aperture-1) *widthstep_new];//Add the following}}//calculate the column sum of the width_aperture rows int sum_aperture=0;for (int x= STARTX;X&LT;=WIDTH_NEW-STARTX-1;++X) {//first element of each line, width_aperture columns and if (X==STARTX) {for (int k=0;k<=width_ APERTURE-1;++K) {sum_aperture+=sum_percol[k];}} else//not the first element {//minus the left sum_aperture-=sum_percol[x-startx-1];//plus the right Sum_aperture+=sum_percol[x+startx];} Averaging uchar meanvalue=sum_aperture/pixelcount;col_dst[0]=meanvalue;//sliding one pixel col_dst++;//col_new++;// There is no need to slide the source image pointer}//the next line row_dst+=width_dst;row_aperture_new+=width_new;}} </span>

Test results:

Original

Results

High-efficiency mean filtering (using Copymakeborder to process boundary pixels)