Added box_percent_covered()

dlib/image_processing/box_overlap_testing.h

@@ -34,6 +34,29 @@ namespace dlib
         return box_intersection_over_union(drectangle(a),drectangle(b));
     }
 
+// ----------------------------------------------------------------------------------------
+
+    inline double box_percent_covered (
+        const drectangle& a,
+        const drectangle& b
+    ) 
+    {
+        const double inner = a.intersect(b).area();
+        if (inner == 0)
+            return 0;
+        return std::max(inner/a.area(), inner/b.area());
+    }
+
+// ----------------------------------------------------------------------------------------
+
+    inline double box_percent_covered (
+        const rectangle& a,
+        const rectangle& b
+    ) 
+    {
+        return box_percent_covered(drectangle(a), drectangle(b));
+    }
+
 // ----------------------------------------------------------------------------------------
 
     class test_box_overlap

dlib/image_processing/box_overlap_testing_abstract.h

@@ -32,6 +32,34 @@ namespace dlib
               boxes are empty then returns 0.
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    inline double box_percent_covered (
+        const drectangle& a,
+        const drectangle& b
+    ); 
+    /*!
+        ensures
+            - let OVERLAP = a.intersect(b).area()
+            - This function returns max(OVERLAP/a.area(), OVERLAP/b.area())
+              e.g. If one box entirely contains another then this function returns 1, if
+              they don't overlap at all it returns 0.
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    inline double box_percent_covered (
+        const rectangle& a,
+        const rectangle& b
+    ); 
+    /*!
+        ensures
+            - let OVERLAP = a.intersect(b).area()
+            - This function returns max(OVERLAP/a.area(), OVERLAP/b.area())
+              e.g. If one box entirely contains another then this function returns 1, if
+              they don't overlap at all it returns 0.
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     class test_box_overlap