    // Copyright (C) 2013  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #undef DLIB_REMOVE_UnOBTAINABLE_RECTANGLES_ABSTRACT_H__
    #ifdef DLIB_REMOVE_UnOBTAINABLE_RECTANGLES_ABSTRACT_H__

    #include "scan_image_pyramid_abstract.h"
    #include "scan_image_boxes_abstract.h"
    #include "scan_image_custom_abstract.h"
    #include "scan_fhog_pyramid_abstract.h"
    #include "../svm/structural_object_detection_trainer_abstract.h"
    #include "../geometry.h"

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        template <
            typename image_scanner_type,
            typename image_array_type,
            typename Pyramid_type
            >
        std::vector<std::vector<rectangle> > remove_unobtainable_rectangles (
            const structural_object_detection_trainer<image_scanner_type>& trainer,
            const image_array_type& images,
            std::vector<std::vector<rectangle> >& object_locations
        );
        /*!
            requires
                - image_scanner_type must be either scan_image_boxes, scan_image_pyramid,
                  scan_image_custom, or scan_fhog_pyramid.
                - images.size() == object_locations.size()
            ensures
                - Recall that the image scanner objects can't produce all possible rectangles
                  as object detections since they only consider a limited subset of all possible
                  object positions.  Moreover, the structural_object_detection_trainer requires
                  its input training data to not contain any object positions which are unobtainable
                  by its scanner object.  Therefore, remove_unobtainable_rectangles() is a tool
                  to filter out these unobtainable rectangles from the training data before giving
                  it to a structural_object_detection_trainer.
                - This function interprets object_locations[i] as the set of object positions for
                  image[i], for all valid i.
                - In particular, this function removes unobtainable rectangles from object_locations
                  and also returns a vector V such that:
                    - V.size() == object_locations.size()
                    - for all valid i:
                        - V[i] == the set of rectangles removed from object_locations[i]
        !*/

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_REMOVE_UnOBTAINABLE_RECTANGLES_ABSTRACT_H__