#include<cstdio>

#include"opencv2/opencv.hpp"

#include"opencv2/nonfree/nonfree.hpp"

using namespace cv ;

int main(){

    Mat m = imread("test.jpg");

    SIFT sift;

    vector<KeyPoint> key_points;

    Mat descriptors;

    sift(m, Mat(), key_points, descriptors);

    printf("keypoints num:[%d]\n",key_points.size());

    MatIterator_<float> start,end;

    start = descriptors.begin<float>();

    end = descriptors.end<float>();

    int vec_dem = 0;

    for(;start != end ;++start ){

        ++ vec_dem ;

        if (vec_dem <128)

            printf("%f\t",(*start));

        else if(vec_dem == 128){

            printf("%f\n",(*start));

            vec_dem = 0;

        }

    }

    return 0;  

}