fixed handling of empty data detections

pyCamSet/calibration_targets/target_detections.py

@@ -214,6 +214,12 @@ def __add__(self, other:TargetDetection) -> TargetDetection:
                              f'Detection 1 names: {other.names}')
         self._glomp_buffer()
         other._glomp_buffer()
+        if self._data is None:
+            if other._data is None:
+                return self
+            return other
+        if other._data is None:
+            return self
         if self._data.shape[0] == 0:
             if other._data.shape[0] == 0:
                 shared_data = self._data
@@ -247,6 +253,7 @@ def add_detection(self, cam_name, im_num, detection: ImageDetection) -> None:
                 , axis=1)
             self._update_buffer.append(observation)
 
+
     def _glomp_buffer(self) -> None:
         """
         Incorporates the update buffer before use.

setup.cfg

@@ -1,8 +1,7 @@
 [metadata]
 name = pyCamSet
 
-
-version = 0.5.5
+version = 0.5.6
 author = Robin Laven
 author_email = r.laven@auckland.ac.nz
 description = Object oriented cameras for computer vision