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gradient.cpp
146 lines (145 loc) · 4.36 KB
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gradient.cpp
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#include "gradient.h"
#include "OfflineGridUBytePicture.h"
//judge the gradient area in terms of (x,y)
template <typename _T>
int Judge( _T x, _T y) //
{
if( x==0&&y==0 )
return 0;
if ( x>0&&y==0 )
return 0;
if ( y>0&&x>y )
return 1;
if ( x>0&&y==x )
return 2;
if ( x>0&&x<y )
return 3;
if ( x==0&&y>0 )
return 4;
if ( x<0&&y>(abs(x)) )
return 5;
if ( x<0&&y==(abs(x)))
return 6;
if ( x<0&&y<(abs(x))&&y>0 )
return 7;
if ( y==0&&x<0 )
return 8;
if ( y<0&&y>x )
return 9;
if ( x<0&&y==x )
return 10;
if ( x<0&&y<x )
return 11;
if ( x==0&&y<0 )
return 12;
if ( y<0&&x<(abs(y))&&x>0 )
return 13;
if ( y<0&&x==(abs(y)) )
return 14;
if ( y<0&&x>(abs(y)) )
return 15;
else
return 0;
}
void FeaExtractByGradient(cv::Mat img, vector<cv::Mat> &featureMaps)
{
float Gx;
float Gy;
int us_direction=8;
int imgHeight=img.rows;
int imgWidth=img.cols;
int v_gx [maskHeight][maskWidth]={};
int v_gy [maskHeight][maskWidth]={};
int image[maskHeight][maskWidth]={};
//make some confirm
for(int i=0;i<maskHeight;i++){
for(int j=0;j<maskWidth;j++){
image[i][j]=img.at<uchar>(i,j);
}
}
//Use Sobel to compute the gradient value of each pixel
for(int i=0;i<maskHeight;i++)
{
for(int j=0;j<maskWidth;j++)
{
if((i==maskHeight-1)||(j==maskWidth-1)||(i==0)||(j==0))
{
v_gx[i][j]=image[i][j];
v_gy[i][j]=image[i][j];
}
else
{
v_gx[i][j]=image[i-1][j-1]+2*image[i-1][j]+image[i-1][j+1]-image[i+1][j-1]-2*image[i+1][j]-image[i+1][j+1];
v_gy[i][j]=image[i-1][j-1]+2*image[i][j-1]+image[i+1][j-1]-image[i-1][j+1]-2*image[i][j+1]-image[i+1][j+1];
}
}
}
float * v_G=new float[maskHeight*maskWidth*us_direction];
//Decompose each gradient value vector to eight directions
for(int i=0;i<maskHeight;i++)
{
for(int j=0;j<maskWidth;j++)
{
Gx=(float)v_gx[i][j];
Gy=(float)v_gy[i][j];
int us_index=i*maskWidth+j;
int Dec_Pos=Judge(Gx,Gy);
switch(Dec_Pos)
{
case 0: v_G[us_index]=Gx;break;
case 1: v_G[us_index]=Gx-Gy;v_G[maskHeight*maskWidth+us_index]=(float)1.414214*Gy;break;
case 2: v_G[maskHeight*maskWidth+us_index]=(float)1.414214*Gy;break;
case 3: v_G[maskHeight*maskWidth+us_index]=(float)1.414214*Gx;v_G[maskHeight*maskWidth*2+us_index]=Gy-Gx;break;
case 4: v_G[maskHeight*maskWidth*2+us_index]=Gy;break;
case 5: v_G[maskHeight*maskWidth*2+us_index]=Gx+Gy;v_G[maskHeight*maskWidth*3+us_index]=(float)1.414214*abs(Gx);break;//abs(1.414214*Gx);break;
case 6: v_G[maskHeight*maskWidth*3+us_index]=(float)1.414214*Gy;break;
case 7: v_G[maskHeight*maskWidth*3+us_index]=(float)1.414214*Gy;v_G[maskHeight*maskWidth*4+us_index]=abs(Gx+Gy);break;
case 8: v_G[maskHeight*maskWidth*4+us_index]=abs(Gx);break;
case 9: v_G[maskHeight*maskWidth*4+us_index]=Gy-Gx;v_G[maskHeight*maskWidth*5+us_index]=(float)1.414214*abs(Gy);break;
case 10:v_G[maskHeight*maskWidth*5+us_index]=(float)1.414214*abs(Gy);break;
case 11:v_G[maskHeight*maskWidth*5+us_index]=(float)1.414214*abs(Gx);v_G[maskHeight*maskWidth*6+us_index]=Gx-Gy;break;
case 12:v_G[maskHeight*maskWidth*6+us_index]=abs(Gy);break;
case 13:v_G[maskHeight*maskWidth*6+us_index]=abs(Gx+Gy);v_G[maskHeight*maskWidth*7+us_index]=(float)1.414214*abs(Gx);break;
case 14:v_G[maskHeight*maskWidth*7+us_index]=(float)1.414214*Gx;break;
case 15:v_G[maskHeight*maskWidth*7+us_index]=(float)1.414214*abs(Gy);v_G[us_index]=abs(Gx+Gy);break;
}
}
}
for(int c=0;c<us_direction;c++)
{
float min=9999999;
float max=-1;
cv::Mat graFeaMap(maskHeight,maskHeight,CV_8UC1);
for(int i=0;i<maskHeight;i++)
{
for(int j=0;j<maskWidth;j++)
{
//make some confirm
if(v_G[c*maskHeight*maskWidth+i*maskWidth+j]<0)
{
v_G[c*maskHeight*maskWidth+i*maskWidth+j]=0;
}
if(max<v_G[c*maskHeight*maskWidth+i*maskWidth+j])
{
max=v_G[c*maskHeight*maskWidth+i*maskWidth+j];
}
if(min>v_G[c*maskHeight*maskWidth+i*maskWidth+j])
{
min=v_G[c*maskHeight*maskWidth+i*maskWidth+j];
}
}
}
for(int i=0;i<maskHeight;i++)
{
for(int j=0;j<maskWidth;j++)
{
v_G[c*maskHeight*maskWidth+i*maskWidth+j]=255*((float)(v_G[c*maskHeight*maskWidth+i*maskWidth+j]-min))/(max-min);// confirm 0-255
graFeaMap.at<uchar>(i,j)=(uchar)v_G[c*maskHeight*maskWidth+i*maskWidth+j];
}
}
GaussianBlur(graFeaMap,graFeaMap,Size(3, 3),0,0);
featureMaps.push_back(graFeaMap);
graFeaMap.release();
}
delete[]v_G;
}