Fix RandomFlip3D in test time augmentation

docs/tutorials/data_pipeline.md

@@ -38,14 +38,24 @@ test_pipeline = [
     dict(
         type='MultiScaleFlipAug',
         img_scale=(1333, 800),
+        pts_scale_ratio=1.0,
         flip=False,
+        pcd_horizontal_flip=False,
+        pcd_vertical_flip=False,
         transforms=[
-            dict(type='Resize', keep_ratio=True),
-            dict(type='RandomFlip'),
-            dict(type='Normalize', **img_norm_cfg),
-            dict(type='Pad', size_divisor=32),
-            dict(type='ImageToTensor', keys=['img']),
-            dict(type='Collect', keys=['img']),
+            dict(
+                type='GlobalRotScaleTrans',
+                rot_range=[0, 0],
+                scale_ratio_range=[1., 1.],
+                translation_std=[0, 0, 0]),
+            dict(type='RandomFlip3D'),
+            dict(
+                type='PointsRangeFilter', point_cloud_range=point_cloud_range),
+            dict(
+                type='DefaultFormatBundle3D',
+                class_names=class_names,
+                with_label=False),
+            dict(type='Collect3D', keys=['points'])
         ])
 ]
 ```
@@ -122,7 +132,8 @@ For each operation, we list the related dict fields that are added/updated/remov
 
 ### Test time augmentation
 
-`MultiScaleFlipAug`
+`MultiScaleFlipAug3D`
+- update: all the dict fields (update values to the collection of augmented data)
 
 ## Extend and use custom pipelines
 

mmdet3d/datasets/pipelines/test_time_aug.py

@@ -17,10 +17,17 @@ class MultiScaleFlipAug3D(object):
         pts_scale_ratio (float | list[float]): Points scale ratios for
             resizing.
         flip (bool): Whether apply flip augmentation. Default: False.
-        flip_direction (str | list[str]): Flip augmentation directions,
-            options are "horizontal" and "vertical". If flip_direction is list,
-            multiple flip augmentations will be applied.
-            It has no effect when flip == False. Default: "horizontal".
+        flip_direction (str | list[str]): Flip augmentation directions
+            for images, options are "horizontal" and "vertical".
+            If flip_direction is list, multiple flip augmentations will
+            be applied. It has no effect when flip == False.
+            Default: "horizontal".
+        pcd_horizontal_flip (bool): Whether apply horizontal flip augmentation
+            to point cloud. Default: True. Note that it works only when
+            'flip' is turned on.
+        pcd_vertical_flip (bool): Whether apply vertical flip augmentation
+            to point cloud. Default: True. Note that it works only when
+            'flip' is turned on.
     """
 
     def __init__(self,
@@ -28,7 +35,9 @@ class MultiScaleFlipAug3D(object):
                  img_scale,
                  pts_scale_ratio,
                  flip=False,
-                 flip_direction='horizontal'):
+                 flip_direction='horizontal',
+                 pcd_horizontal_flip=True,
+                 pcd_vertical_flip=True):
         self.transforms = Compose(transforms)
         self.img_scale = img_scale if isinstance(img_scale,
                                                  list) else [img_scale]
@@ -39,30 +48,46 @@ class MultiScaleFlipAug3D(object):
         assert mmcv.is_list_of(self.pts_scale_ratio, float)
 
         self.flip = flip
+        self.pcd_horizontal_flip = pcd_horizontal_flip
+        self.pcd_vertical_flip = pcd_vertical_flip
+
         self.flip_direction = flip_direction if isinstance(
             flip_direction, list) else [flip_direction]
         assert mmcv.is_list_of(self.flip_direction, str)
         if not self.flip and self.flip_direction != ['horizontal']:
             warnings.warn(
                 'flip_direction has no effect when flip is set to False')
-        if (self.flip
-                and not any([t['type'] == 'RandomFlip' for t in transforms])):
+        if (self.flip and not any([(t['type'] == 'RandomFlip3D'
+                                    or t['type'] == 'RandomFlip')
+                                   for t in transforms])):
             warnings.warn(
                 'flip has no effect when RandomFlip is not in transforms')
 
     def __call__(self, results):
         aug_data = []
         flip_aug = [False, True] if self.flip else [False]
+        pcd_horizontal_flip_aug = [False, True] \
+            if self.flip and self.pcd_horizontal_flip else [False]
+        pcd_vertical_flip_aug = [False, True] \
+            if self.flip and self.pcd_vertical_flip else [False]
         for scale in self.img_scale:
             for pts_scale_ratio in self.pts_scale_ratio:
                 for flip in flip_aug:
+                    for pcd_horizontal_flip in pcd_horizontal_flip_aug:
+                        for pcd_vertical_flip in pcd_vertical_flip_aug:
                             for direction in self.flip_direction:
-                        # results.copy will cause bug since it is shallow copy
+                                # results.copy will cause bug
+                                # since it is shallow copy
                                 _results = deepcopy(results)
                                 _results['scale'] = scale
                                 _results['flip'] = flip
-                        _results['pcd_scale_factor'] = pts_scale_ratio
+                                _results['pcd_scale_factor'] = \
+                                    pts_scale_ratio
                                 _results['flip_direction'] = direction
+                                _results['pcd_horizontal_flip'] = \
+                                    pcd_horizontal_flip
+                                _results['pcd_vertical_flip'] = \
+                                    pcd_vertical_flip
                                 data = self.transforms(_results)
                                 aug_data.append(data)
         # list of dict to dict of list

mmdet3d/datasets/pipelines/transforms_3d.py

@@ -47,6 +47,11 @@ class RandomFlip3D(RandomFlip):
 
     def random_flip_data_3d(self, input_dict, direction='horizontal'):
         assert direction in ['horizontal', 'vertical']
+        if len(input_dict['bbox3d_fields']) == 0:  # test mode
+            input_dict['bbox3d_fields'].append('empty_box3d')
+            input_dict['empty_box3d'] = input_dict['box_type_3d'](
+                np.array([], dtype=np.float32))
+        assert len(input_dict['bbox3d_fields']) == 1
         for key in input_dict['bbox3d_fields']:
             input_dict['points'] = input_dict[key].flip(
                 direction, points=input_dict['points'])