Merged and also updated documentation to reflect these changes.

dlib/image_transforms/fhog.h

@@ -1058,7 +1058,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog(
         const dlib::array<array2d<T,mm1>,mm2>& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     )
     {
         // make sure requires clause is not broken
@@ -1084,7 +1085,7 @@ namespace dlib
                     const float val = hog[d][r/cell_draw_size][c/cell_draw_size] +
                         hog[d+mbars.size()][r/cell_draw_size][c/cell_draw_size] +
                         hog[d+mbars.size()*2][r/cell_draw_size][c/cell_draw_size];
-                    if (val > 0)
+                    if (val > min_response_threshold)
                     {
                         set_subm(himg, r, c, cell_draw_size, cell_draw_size) += val*mbars[d%mbars.size()];
                     }
@@ -1106,7 +1107,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog (
         const std::vector<matrix<T> >& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     )
     {
         // make sure requires clause is not broken
@@ -1131,7 +1133,7 @@ namespace dlib
                 }
             }
         }
-        return draw_fhog(temp,cell_draw_size);
+        return draw_fhog(temp,cell_draw_size, min_response_threshold);
     }
 
 // ----------------------------------------------------------------------------------------
@@ -1142,7 +1144,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog(
         const array2d<matrix<T,31,1>,mm>& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     )
     {
         // make sure requires clause is not broken
@@ -1167,7 +1170,7 @@ namespace dlib
                     const float val = hog[r/cell_draw_size][c/cell_draw_size](d) +
                         hog[r/cell_draw_size][c/cell_draw_size](d+mbars.size()) +
                         hog[r/cell_draw_size][c/cell_draw_size](d+mbars.size()*2);
-                    if (val > 0)
+                    if (val > min_response_threshold)
                     {
                         set_subm(himg, r, c, cell_draw_size, cell_draw_size) += val*mbars[d%mbars.size()];
                     }

dlib/image_transforms/fhog_abstract.h

@@ -271,7 +271,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog(
         const dlib::array<array2d<T,mm1>,mm2>& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     );
     /*!
         requires
@@ -285,6 +286,8 @@ namespace dlib
               then returned.
             - The size of the cells in the output image will be rendered as cell_draw_size 
               pixels wide and tall.
+            - HOG cells with a response value less than min_response_threshold are not
+              drawn.
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -294,7 +297,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog (
         const std::vector<matrix<T> >& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     );
     /*!
         requires
@@ -303,6 +307,8 @@ namespace dlib
         ensures
             - This function just converts the given hog object into an array<array2d<T>>
               and passes it to the above draw_fhog() routine and returns the results.
+            - HOG cells with a response value less than min_response_threshold are not
+              drawn.
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -313,7 +319,8 @@ namespace dlib
         >
     matrix<unsigned char> draw_fhog(
         const array2d<matrix<T,31,1>,mm>& hog,
-        const long cell_draw_size = 15
+        const long cell_draw_size = 15,
+        const float min_response_threshold = 0.0
     );
     /*!
         requires
@@ -326,6 +333,8 @@ namespace dlib
               then returned.
             - The size of the cells in the output image will be rendered as cell_draw_size 
               pixels wide and tall.
+            - HOG cells with a response value less than min_response_threshold are not
+              drawn.
     !*/
 
 // ----------------------------------------------------------------------------------------