After subraction of 4 neighbor pixels always give zero - c++

Question

I am trying to take difference of center pixel with 4 neighbor and add them and then replace the original with that difference value. but it always replace pixel with zero. I don't what i am doing wrong. thanks for any help
// newproject.cpp : Defines the entry point for the console application.
#include "stdafx.h"
#include "highgui.h"
#include <stdio.h>
#include <cv.h>
#include <highgui.h>
#include <stdio.h>
#include <conio.h>
#include <opencv2/imgproc/imgproc.hpp> // Gaussian Blur
#include <opencv2/core/core.hpp> // Basic OpenCV structures (cv::Mat, Scalar)
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <conio.h>
using namespace cv;
using namespace std;
class frameprocessing{
Mat hsv_base;
MatND hist_base;
public:
void whatever(Mat Frame)
{
for(int i=0;i<Frame.cols;i++)
for(int j=0;j<Frame.rows;j++)
{
if(i==0&&j==0)
{
// cout<<"Check 1"<<endl;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i)-(Frame.at<Vec3b>(j+1,i))+(Frame.at<Vec3b>(j,i)-Frame.at<Vec3b>(j,i+1))+(Frame.at<Vec3b>(j,i)-Frame.at<Vec3b>(j+1,i))+(Frame.at<Vec3b>(j,i)-Frame.at<Vec3b>(j,i+1)));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(i==Frame.cols-1&&j==Frame.rows-1)
{
// cout<<"Check 2"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i-1)+Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i-1)+Frame.at<Vec3b>(j,i)));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(i==Frame.cols-1&&j==0)
{
//cout<<"Check 3"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i-1)+Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i-1)+Frame.at<Vec3b>(j,i)));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(i==0&&j==Frame.rows-1)
{
// cout<<"Check 4"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)+Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)+Frame.at<Vec3b>(j,i)));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(i==0)
{
// cout<<"Check 5"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)-Frame.at<Vec3b>(j,i))+((Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(j==0)
{
// cout<<"Check 6"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)-Frame.at<Vec3b>(j,i)+(Frame.at<Vec3b>(j,i-1)-Frame.at<Vec3b>(j,i))));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(i==Frame.cols-1)
{
// cout<<"Check 7"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+((Frame.at<Vec3b>(j,i-1)-Frame.at<Vec3b>(j,i)))+((Frame.at<Vec3b>(j,i-1)-Frame.at<Vec3b>(j,i))));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else if(j==Frame.rows-1)
{
// cout<<"Check 8"<<endl;
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b(j,i+1)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+((Frame.at<Vec3b>(j,i-1)-Frame.at<Vec3b>(j,i))));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
}
else
{
Frame.at<Vec3b>(j,i)=((Frame.at<Vec3b>(j-1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j+1,i)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i+1)-Frame.at<Vec3b>(j,i))+(Frame.at<Vec3b>(j,i-1)+Frame.at<Vec3b>(j,i)));
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[0]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[1]/4;
Frame.at<Vec3b>(j,i)=(Frame.at<Vec3b>(j,i))[2]/4;
Vec3d value = Frame.at<Vec3b>(j,i);
cout<<value[0]<<endl;
cout<<value[1]<<endl;
cout<<value[2]<<endl;
}
}
//hell(Frame);
}
};
class video{
Mat frame;
string filename;
double dWidth;
double dHeight;
public:
video()
{
}
video(string videoname)
{
vector<Mat> videoframes;
filename = videoname;
VideoCapture capture(filename);
if( !capture.isOpened() )
{
exit(0);
}
dWidth = capture.get(CV_CAP_PROP_FRAME_WIDTH); //get the width of frames of the video
dHeight = capture.get(CV_CAP_PROP_FRAME_HEIGHT); //get the height of frames of the video
frameprocessing obj;
for( ; ; )
{
capture >> frame;
if(frame.empty())
break;
// Mat tmp=frame.clone();
obj.whatever(frame);
// obj.hsv_histogram(frame);
// videoframes.push_back(tmp);
}
//displayvideo(videoframes);
//writer(videoframes);
}
};
int _tmain(int argc, _TCHAR* argv[])
{
video obj("video.avi");

Answer 1

It seems you need Lapacian with kernel size parameter = 1, see here: http://docs.opencv.org/modules/imgproc/doc/filtering.html?highlight=laplacian#laplacian
You just need divide result by 4 after convolution for correct Laplacian.
As for your code, I think you should use different images as source and destination, you cant do this inplace.
class frameprocessing{
Mat hsv_base;
MatND hist_base;
public:
void whatever(Mat Frame)
{
Frame.convertTo(Frame,CV_32FC3);
Mat newimage=Mat::zeros(Frame.size(),CV_32FC3);
for (int j=1;j<Frame.rows-1;++j)
{
for (int i=1;i<Frame.cols-1;++i)
{
newimage.at<Vec3f>(j,i)=Frame.at<Vec3f>(j,i)-
0.25*Frame.at<Vec3f>(j+1,i)-
0.25*Frame.at<Vec3f>(j,i+1)-
0.25*Frame.at<Vec3f>(j-1,i)-
0.25*Frame.at<Vec3f>(j,i-1);
cout << newimage.at<Vec3f>(j,i) << endl;
}
}
//imshow("result",newimage);
//cv::waitKey(30);
}
};
class video{
Mat frame;
string filename;
double dWidth;
double dHeight;
public:
video()
{
}
video(string videoname)
{
vector<Mat> videoframes;
filename = videoname;
VideoCapture capture(filename);
if( !capture.isOpened() )
{
exit(0);
}
dWidth = capture.get(cv::CAP_PROP_FRAME_WIDTH); //get the width of frames of the video
dHeight = capture.get(cv::CAP_PROP_FRAME_HEIGHT); //get the height of frames of the video
frameprocessing obj;
for( ; ; )
{
capture >> frame;
if(frame.empty())
break;
// Mat tmp=frame.clone();
obj.whatever(frame);
// obj.hsv_histogram(frame);
// videoframes.push_back(tmp);
}
//displayvideo(videoframes);
//writer(videoframes);
}
};
int main(int argc, char* argv[])
{
namedWindow("result");
video obj("D:\\ImagesForTest\\atrium.avi");
}