# Blurring issues (only 1/3 of the image is blurred)

Hello, I am trying for days to figure out what the prolem is in my loop or blurring function. I get only the right 1/3 of the image blurred. Please help!

```
void Blurring (const Mat& input, Mat& output)
{
float sum;
float neighborhood[3][3] = {
{1/9.0, 1/9.0, 1/9.0},
{1/9.0, 1/9.0, 1/9.0},
{1/9.0, 1/9.0, 1/9.0}
};
for(int y = 0; y < input.rows; y++)
for(int x = 0; x < input.cols; x++)
output.at<unsigned char>(y,x) = 0.0;
output = input.clone();
//bluring operation
for(int y = 1; y < input.rows - 1; y++){
for(int x = 1; x < input.cols - 1; x++){
sum = 0.0;
for(int k = -1; k <= 1;k++){
for(int j = -1; j <=1; j++){
sum = sum + neighborhood[j+1][k+1]*input.at<unsigned char>(y - j, x - k);
}
}
output.at<unsigned char>(y,x) = sum;
}
}
}
```