사용한 라이브러리

Q.9. 가우시안 필터

int main()
{
    PPM ppm("imori_noise.pnm");
    int width = ppm.Get_width();
    int height = ppm.Get_height();
    PPM ppm2(width, height);

    auto kernel = [&](int i, int j)
    {
        double ret = 2;
        if (i == 0 && j == 0) ret = 4;
        else if (abs(i) == 1 && abs(j)==1) ret = 1;
        return ret;// / 16.;
    };

    auto conv = [&](const std::vector<std::vector<double>> &f)
    {
        std::vector < std::vector < double >> ret(width, std::vector<double>(height));
        for(int j=0; j<height; j++)
            for (int i = 0; i < width; i++)
            {
                ret[i][j] = 0;
            }
        for (int j = 0; j < height; j++)
            for (int i = 0; i < width; i++)
            {
                int sum = 0;
                for(int di=-1; di<=1; di++)
                    for (int dj = -1; dj <= 1; dj++)
                    {
                        if (i - di >= 0 && i - di < width && j - dj >= 0 && j - di < height)
                        {
                            ret[i][j] += kernel(di, dj) * f[i - di][j - dj];
                            sum += kernel(di, dj);
                        }
                    }
                ret[i][j] /= (double)sum;
            }
        return ret;
    };

    std::vector < std::vector < double >> arrr(width, std::vector<double>(height));
    std::vector < std::vector < double >> arrg(width, std::vector<double>(height));
    std::vector < std::vector < double >> arrb(width, std::vector<double>(height));
    for (int j = 0; j < height; j++)
        for (int i = 0; i < width; i++)
        {
            arrr[i][j] = ppm(i, j, 'r');
            arrg[i][j] = ppm(i, j, 'g');
            arrb[i][j] = ppm(i, j, 'b');
        }
    arrr = conv(arrr);
    arrg = conv(arrg);
    arrb = conv(arrb);

    for (int j = 0; j < height; j++)
        for (int i = 0; i < width; i++)
        {
            ppm2(i, j, 'r') = arrr[i][j];
            ppm2(i, j, 'g') = arrg[i][j];
            ppm2(i, j, 'b') = arrb[i][j];
        }

    ppm2.Flush("out.ppm");
    return 0;
}