Add distortion factor to TargetMap

Tells us how much each detection was effected by distortion so we can
filter this in the localizer.

Signed-off-by: milind-u <milind.upadhyay@gmail.com>
Change-Id: I3d1ffd3cddad9ec1949c1378558f71a48c534f03
diff --git a/frc971/vision/target_map.fbs b/frc971/vision/target_map.fbs
index 7017e7f..3ad0bd8 100644
--- a/frc971/vision/target_map.fbs
+++ b/frc971/vision/target_map.fbs
@@ -39,6 +39,15 @@
   // NOTE: not filtered by aprilrobotics.cc so that we can log
   // more detections.
   pose_error:double (id: 4);
+
+  // A measure of how much distortion affected this detection.
+  // Only filled out if this pose represents a live detection.
+  // This is computed as the average distance between the distorted
+  // corners and undistorted corners, normalized by the image size
+  // to be between 0-1.
+  // NOTE: not filtered by aprilrobotics.cc so that we can log
+  // more detections.
+  distortion_factor:double (id: 5);
 }
 
 // Map of all target poses on a field.