Removes object points from gt_sampled point cloud which are not in the scope of MAX_SWEEPS (#719)

* Fixes #718

* FIX: replaced wrong part
Co-authored-by: Christian Fruhwirth-Reisinger <christian.reisinger@student.tugraz.at>

pcdet/datasets/dataset.py

@@ -142,6 +142,14 @@ class DatasetTemplate(torch_data.Dataset):
             if data_dict.get('gt_boxes2d', None) is not None:
                 data_dict['gt_boxes2d'] = data_dict['gt_boxes2d'][selected]
              
+        if 'timestamp' in self.dataset_cfg.POINT_FEATURE_ENCODING.get('src_feature_list'):
+            if data_dict.get('points', None) is not None:
+                max_sweeps = self.dataset_cfg.get('MAX_SWEEPS', 1)
+                idx = self.dataset_cfg.POINT_FEATURE_ENCODING.get('src_feature_list').index('timestamp')
+                dt = np.round(data_dict['points'][:, idx], 2)
+                max_dt = sorted(np.unique(dt))[max_sweeps-1]
+                data_dict['points'] = data_dict['points'][dt <= max_dt]
+
         if data_dict.get('points', None) is not None:
             data_dict = self.point_feature_encoder.forward(data_dict)