Upgraded the object_detector. Now it can store multiple weight vectors and hence

multiple object detectors.

dlib/image_processing/scan_fhog_pyramid.h

@@ -865,19 +865,27 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog (
         const object_detector<scan_fhog_pyramid<Pyramid_type> >& detector,
+        const unsigned long weight_index = 0,
         const long cell_draw_size = 15
     )
     {
         // make sure requires clause is not broken
-        DLIB_ASSERT(cell_draw_size > 0 && detector.get_w().size() >= detector.get_scanner().get_num_dimensions() ,
+        DLIB_ASSERT(weight_index < detector.num_detectors(),
             "\t matrix draw_fhog()"
             << "\n\t Invalid arguments were given to this function. "
             << "\n\t cell_draw_size:                              " << cell_draw_size
-            << "\n\t detector.get_w().size():                     " << detector.get_w().size()
+            << "\n\t detector.num_detectors():                    " << detector.num_detectors()
+            );
+        DLIB_ASSERT(cell_draw_size > 0 && detector.get_w(weight_index).size() >= detector.get_scanner().get_num_dimensions(),
+            "\t matrix draw_fhog()"
+            << "\n\t Invalid arguments were given to this function. "
+            << "\n\t cell_draw_size:                              " << cell_draw_size
+            << "\n\t weight_index:                                " << weight_index
+            << "\n\t detector.get_w(weight_index).size():         " << detector.get_w(weight_index).size()
             << "\n\t detector.get_scanner().get_num_dimensions(): " << detector.get_scanner().get_num_dimensions()
             );
 
-        typename scan_fhog_pyramid<Pyramid_type>::fhog_filterbank fb = detector.get_scanner().build_fhog_filterbank(detector.get_w());
+        typename scan_fhog_pyramid<Pyramid_type>::fhog_filterbank fb = detector.get_scanner().build_fhog_filterbank(detector.get_w(weight_index));
         return draw_fhog(fb.get_filters(),cell_draw_size);
     }
 

dlib/image_processing/scan_fhog_pyramid_abstract.h

@@ -17,18 +17,21 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog (
         const object_detector<scan_fhog_pyramid<Pyramid_type> >& detector,
+        const unsigned long weight_index = 0,
         const long cell_draw_size = 15
     );
     /*!
         requires
             - cell_draw_size > 0
+            - weight_index < detector.num_detectors()
             - detector.get_w().size() >= detector.get_scanner().get_num_dimensions()
               (i.e. the detector must have been populated with a HOG filter)
         ensures
-            - Converts the HOG filters in the given detector into an image suitable for
-              display on the screen.  In particular, we draw all the HOG cells into a
-              grayscale image in a way that shows the magnitude and orientation of the
-              gradient energy in each cell.  The resulting image is then returned.
+            - Converts the HOG filters in the given detector (specifically, the filters in
+              detector.get_w(weight_index)) into an image suitable for display on the
+              screen.  In particular, we draw all the HOG cells into a grayscale image in a
+              way that shows the magnitude and orientation of the gradient energy in each
+              cell.  The resulting image is then returned.
     !*/
 
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