Grayscale conversion

void BayerFilter()
{
    Mat original = imread("bayer.bmp", CV_LOAD_IMAGE_GRAYSCALE);

    original.convertTo(original, CV_32FC1, 1.0 / 255.0);
    Mat bayerImg(original.rows, original.cols, CV_32FC3);

    for (int x = 1; x < (original.rows - 1); x++)
    {
        for(int y = 1; y < (original.cols - 1); y++)
        {


            float bayerR = 0.0f;
            float bayerG = 0.0f;
            float bayerB = 0.0f;

            // B - vektikalně G horizontalně G
            if ( x % 2 == 1 && y % 2 == 1)
            {
                bayerB = original.at<float>(x,y);

                bayerG = original.at<float>(x+1, y);
                bayerG += original.at<float>(x-1, y);
                bayerG += original.at<float>(x, y+1);
                bayerG += original.at<float>(x, y-1);
                bayerG = bayerG / 4;

                bayerR = original.at<float>(x+1, y+1);
                bayerR += original.at<float>(x-1, y-1);
                bayerR += original.at<float>(x+1, y-1);
                bayerR += original.at<float>(x-1, y+1);
                bayerR = bayerR / 4;

                bayerImg.at<Vec3f>(x,y)[2] = bayerR;
                bayerImg.at<Vec3f>(x,y)[1] = bayerG;
                bayerImg.at<Vec3f>(x,y)[0] = bayerB;
            }

            // R - vertikalně G horizontalně G
            if ( x % 2 == 0 && y % 2 == 0)
            {
                bayerR = original.at<float>(x,y);

                bayerG = original.at<float>(x+1, y);
                bayerG += original.at<float>(x-1, y);
                bayerG += original.at<float>(x, y+1);
                bayerG += original.at<float>(x, y-1);
                bayerG = bayerG / 4;

                bayerR = original.at<float>(x+1, y+1);
                bayerR += original.at<float>(x-1, y-1);
                bayerR += original.at<float>(x+1, y-1);
                bayerR += original.at<float>(x-1, y+1);
                bayerR = bayerR / 4;

                bayerImg.at<Vec3f>(x,y)[2] = bayerR;
                bayerImg.at<Vec3f>(x,y)[1] = bayerG;
                bayerImg.at<Vec3f>(x,y)[0] = bayerB;
            }
            // G - vertikalně R horizontálně B
            if ( x % 2 == 0 && y % 2 == 1)
            {
                bayerG = original.at<float>(x,y);

                bayerR = original.at<float>(x+1, y);
                bayerR += original.at<float>(x-1, y);
                bayerB = original.at<float>(x, y+1);
                bayerB += original.at<float>(x, y-1);
                bayerB = bayerB / 2;
                bayerR = bayerR / 2;

                bayerImg.at<Vec3f>(x,y)[2] = bayerR;
                bayerImg.at<Vec3f>(x,y)[1] = bayerG;
                bayerImg.at<Vec3f>(x,y)[0] = bayerB;
            }
            // G - vertikalně B horizontálně R
            if ( x % 2 == 0 && y % 2 == 1)
            {
                bayerG = original.at<float>(x,y);

                bayerB = original.at<float>(x+1, y);
                bayerB += original.at<float>(x-1, y);

                bayerR = original.at<float>(x, y+1);
                bayerR += original.at<float>(x, y-1);

                bayerB = bayerB / 2;
                bayerR = bayerR / 2;

                bayerImg.at<Vec3f>(x,y)[2] = bayerR;
                bayerImg.at<Vec3f>(x,y)[1] = bayerG;
                bayerImg.at<Vec3f>(x,y)[0] = bayerB;
            }
        }
    }
    imshow("Bayer", bayerImg);
}