Added overloads of fhog_to_image() and image_to_fhog() that work on rectangles.

dlib/image_transforms/fhog.h

@@ -415,6 +415,17 @@ namespace dlib
         return p/cell_size - point(1,1);
     }
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle image_to_fhog (
+        const rectangle& rect,
+        int cell_size = 8
+    ) 
+    {
+        return rectangle(image_to_fhog(rect.tl_corner(),cell_size),
+                         image_to_fhog(rect.br_corner(),cell_size));
+    }
+
 // ----------------------------------------------------------------------------------------
 
     inline point fhog_to_image (
@@ -426,6 +437,17 @@ namespace dlib
         return (p+point(1,1))*cell_size + point(1,1) + point(cell_size/2,cell_size/2);
     }
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle fhog_to_image (
+        const rectangle& rect,
+        int cell_size = 8
+    ) 
+    {
+        return rectangle(fhog_to_image(rect.tl_corner(),cell_size),
+                         fhog_to_image(rect.br_corner(),cell_size));
+    }
+
 // ----------------------------------------------------------------------------------------
 // ----------------------------------------------------------------------------------------
 

dlib/image_transforms/fhog_abstract.h

@@ -100,6 +100,20 @@ namespace dlib
               input image.
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle image_to_fhog (
+        const rectangle& rect,
+        int cell_size = 8
+    );
+    /*!
+        requires
+            - cell_size > 0
+        ensures
+            - maps a rectangle from image space to fhog space.  In particular this function returns:
+              rectangle(image_to_fhog(rect.tl_corner(),cell_size), image_to_fhog(rect.br_corner(),cell_size))
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     inline point fhog_to_image (
@@ -118,6 +132,20 @@ namespace dlib
               cell_size should be set to the value used by the call to extract_fhog_features().
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle fhog_to_image (
+        const rectangle& rect,
+        int cell_size = 8
+    );
+    /*!
+        requires
+            - cell_size > 0
+        ensures
+            - maps a rectangle from fhog space to image space.  In particular this function returns:
+              rectangle(fhog_to_image(rect.tl_corner(),cell_size), fhog_to_image(rect.br_corner(),cell_size))
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     template <