Added use_relative_feature_weights() and use_uniform_feature_weights()

functions to make it easy to configure image scanners that use the hashed_feature_image.

dlib/image_processing/setup_hashed_features.h

@@ -24,6 +24,36 @@ namespace dlib
         ): error(a) {}
     };
 
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_scanner
+        >
+    void use_uniform_feature_weights (
+        image_scanner& scanner
+    )
+    {
+        typename image_scanner::feature_extractor_type fe;
+        fe.copy_configuration(scanner.get_feature_extractor());
+        fe.use_uniform_feature_weights();
+        scanner.copy_configuration(fe);
+    }
+
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_scanner
+        >
+    void use_relative_feature_weights (
+        image_scanner& scanner
+    )
+    {
+        typename image_scanner::feature_extractor_type fe;
+        fe.copy_configuration(scanner.get_feature_extractor());
+        fe.use_relative_feature_weights();
+        scanner.copy_configuration(fe);
+    }
+
 // ----------------------------------------------------------------------------------------
 // ----------------------------------------------------------------------------------------
 //                                 stuff for scan_image_pyramid
@@ -66,6 +96,7 @@ namespace dlib
         projection_hash phash = create_random_projection_hash(samps, bits);
 
         feature_image<feature_extractor, projection_hash> hfe;
+        hfe.copy_configuration(scanner.get_feature_extractor());
         hfe.set_hash(phash);
         hfe.copy_configuration(fe);
         scanner.copy_configuration(hfe);
@@ -143,6 +174,7 @@ namespace dlib
         projection_hash phash = create_random_projection_hash(samps, bits);
 
         feature_image<feature_extractor, projection_hash> hfe;
+        hfe.copy_configuration(scanner.get_feature_extractor());
         hfe.set_hash(phash);
         hfe.copy_configuration(fe);
         scanner.copy_configuration(hfe);

dlib/image_processing/setup_hashed_features_abstract.h

@@ -22,6 +22,42 @@ namespace dlib
         !*/
     };
 
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_scanner
+        >
+    void use_uniform_feature_weights (
+        image_scanner& scanner
+    );
+    /*!
+        requires
+            - image_scanner should be either scan_image_pyramid or scan_image_boxes and
+              should use the hashed_feature_image as its local feature extractor.
+        ensures
+            - #scanner.get_feature_extractor().uses_uniform_feature_weights() == true
+              (i.e. Make the scanner's feature extractor use the uniform feature weighting
+              scheme)
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_scanner
+        >
+    void use_relative_feature_weights (
+        image_scanner& scanner
+    );
+    /*!
+        requires
+            - image_scanner should be either scan_image_pyramid or scan_image_boxes and
+              should use the hashed_feature_image as its local feature extractor.
+        ensures
+            - #scanner.get_feature_extractor().uses_uniform_feature_weights() == false 
+              (i.e. Make the scanner's feature extractor use the relative feature weighting
+              scheme)
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     template <