A minor change to avoid compiler warnings.

dlib/image_processing/scan_fhog_pyramid.h

@@ -146,7 +146,7 @@ namespace dlib
         {
             friend class scan_fhog_pyramid;
         public:
-            inline unsigned long get_num_dimensions() const
+            inline long get_num_dimensions() const
             {
                 unsigned long dims = 0;
                 for (unsigned long i = 0; i < filters.size(); ++i)

dlib/image_processing/scan_fhog_pyramid_abstract.h

@@ -360,7 +360,7 @@ namespace dlib
             !*/
 
         public:
-            unsigned long get_num_dimensions(
+            long get_num_dimensions(
             ) const;
             /*!
                 ensures