*                      descriptors for the provided keypoints

     */

    CV_WRAP_AS(detectAndCompute) virtual void operator()( InputArray image, InputArray mask,

                                     OutputArray descriptors,

                                     bool useProvidedKeypoints=false ) const = 0;

                    CV_OUT vector<KeyPoint>& keypoints) const;

    //! finds the keypoints and computes their descriptors. Optionally it can compute descriptors for the user-provided keypoints

    void operator()(InputArray img, InputArray mask,

                    OutputArray descriptors,

                    bool useProvidedKeypoints=false) const;