[Fix] fix bugs for 3DSSD triggered by empty GT (#258)

* add h3d backbone

* add h3d backbone

* add h3dnet

* modify scannet config

* fix bugs for proposal refine

* fix bugs for test backbone

* add primitive head test

* modify h3dhead

* modify h3d head

* update loss weight config

* fix bugs for h3d head loss

* modify h3d head get targets function

* update h3dnet base config

* modify weighted loss

* Revert "Merge branch 'h3d_u2' into 'master'"

This reverts merge request !5

* fix bugs for empty scene

* modify doc

* modify filter empty scene

mmdet3d/datasets/custom_3d.py

@@ -105,7 +105,7 @@ class Custom3DDataset(Dataset):
         if not self.test_mode:
             annos = self.get_ann_info(index)
             input_dict['ann_info'] = annos
-            if self.filter_empty_gt and len(annos['gt_bboxes_3d']) == 0:
+            if self.filter_empty_gt and ~(annos['gt_labels_3d'] != -1).any():
                 return None
         return input_dict
 
@@ -149,8 +149,9 @@ class Custom3DDataset(Dataset):
             return None
         self.pre_pipeline(input_dict)
         example = self.pipeline(input_dict)
-        if self.filter_empty_gt and (example is None or len(
-                example['gt_bboxes_3d']._data) == 0):
+        if self.filter_empty_gt and \
+                (example is None or
+                    ~(example['gt_labels_3d']._data != -1).any()):
             return None
         return example
 

mmdet3d/models/dense_heads/ssd_3d_head.py

@@ -335,6 +335,30 @@ class SSD3DHead(VoteHead):
         valid_gt = gt_labels_3d != -1
         gt_bboxes_3d = gt_bboxes_3d[valid_gt]
         gt_labels_3d = gt_labels_3d[valid_gt]
+
+        # Generate fake GT for empty scene
+        if valid_gt.sum() == 0:
+            vote_targets = points.new_zeros(self.num_candidates, 3)
+            center_targets = points.new_zeros(self.num_candidates, 3)
+            size_res_targets = points.new_zeros(self.num_candidates, 3)
+            dir_class_targets = points.new_zeros(
+                self.num_candidates, dtype=torch.int64)
+            dir_res_targets = points.new_zeros(self.num_candidates)
+            mask_targets = points.new_zeros(
+                self.num_candidates, dtype=torch.int64)
+            centerness_targets = points.new_zeros(self.num_candidates,
+                                                  self.num_classes)
+            corner3d_targets = points.new_zeros(self.num_candidates, 8, 3)
+            vote_mask = points.new_zeros(self.num_candidates, dtype=torch.bool)
+            positive_mask = points.new_zeros(
+                self.num_candidates, dtype=torch.bool)
+            negative_mask = points.new_ones(
+                self.num_candidates, dtype=torch.bool)
+            return (vote_targets, center_targets, size_res_targets,
+                    dir_class_targets, dir_res_targets, mask_targets,
+                    centerness_targets, corner3d_targets, vote_mask,
+                    positive_mask, negative_mask)
+
         gt_corner3d = gt_bboxes_3d.corners
 
         (center_targets, size_targets, dir_class_targets,