Я пытаюсь понять, как получить дескриптор для данногоKeyPoint в OpenCV. Пока мой код выглядит следующим образом:

#include 
#include "opencv2/opencv.hpp"

typedef cv::Mat Image;

int main(int argc, const char * argv[])
{

    Image imgA = cv::imread("images/buddhamulticam_total100.png",
                              CV_LOAD_IMAGE_GRAYSCALE);
    Image imgB = cv::imread("images/buddhamulticam_total101.png", 
                            CV_LOAD_IMAGE_GRAYSCALE);

    cv::Ptr detector = 
                    cv::FeatureDetector::create("ORB");
    cv::Ptr descriptor = 
                    cv::DescriptorExtractor::create("ORB");

    std::vector keyPointsA, keyPointsB;

    keyPointsA.push_back(cv::KeyPoint(0,0,5));
    keyPointsB.push_back(cv::KeyPoint(10,10,5));

    cv::Mat descriptorA, descriptorB;
    descriptor->compute(imgA, keyPointsA, descriptorA);
    descriptor->compute(imgB, keyPointsB, descriptorB);

    std::cout < "DescriptorA (" < descriptorA.rows < "," <                 descriptorA.cols < ")" < std::endl;
    std::cout < "DescriptorB (" < descriptorB.rows < "," 
              < descriptorB.cols < ")" < std::endl;
    return 0;
}