[feature]: support ssd_3d_head in 3DSSD (#83)

* add ssd3dhead

* fix bugs for anchorfreebboxcoder

* modify ssd 3d head

* modify ssd 3d head

* reconstruct ssd3dhead and votehead

* add unittest

* modify 3dssd config

* modify 3dssd head

* modify 3dssd head

* rename base conv bbox head

* modify vote module

* modify 3dssd config

* fix bugs for unittest

* modify test_heads.py

* fix bugs for h3d bbox head

* add 3dssd detector

* fix bugs for 3dssd config

* modify base conv bbox head

* modify base conv bbox head

* modify base conv bbox head

configs/3dssd/3dssd_kitti-3d-car.py

+_base_ = [
+    '../_base_/models/3dssd.py', '../_base_/datasets/kitti-3d-car.py',
+    '../_base_/default_runtime.py'
+]
+
+# dataset settings
+dataset_type = 'KittiDataset'
+data_root = 'data/kitti/'
+class_names = ['Car']
+point_cloud_range = [0, -40, -5, 70, 40, 3]
+input_modality = dict(use_lidar=True, use_camera=False)
+db_sampler = dict(
+    data_root=data_root,
+    info_path=data_root + 'kitti_dbinfos_train.pkl',
+    rate=1.0,
+    prepare=dict(filter_by_difficulty=[-1], filter_by_min_points=dict(Car=5)),
+    classes=class_names,
+    sample_groups=dict(Car=15))
+
+file_client_args = dict(backend='disk')
+# Uncomment the following if use ceph or other file clients.
+# See https://mmcv.readthedocs.io/en/latest/api.html#mmcv.fileio.FileClient
+# for more details.
+# file_client_args = dict(
+#     backend='petrel', path_mapping=dict(data='s3://kitti_data/'))
+
+train_pipeline = [
+    dict(
+        type='LoadPointsFromFile',
+        load_dim=4,
+        use_dim=4,
+        file_client_args=file_client_args),
+    dict(
+        type='LoadAnnotations3D',
+        with_bbox_3d=True,
+        with_label_3d=True,
+        file_client_args=file_client_args),
+    dict(type='PointsRangeFilter', point_cloud_range=point_cloud_range),
+    dict(type='ObjectRangeFilter', point_cloud_range=point_cloud_range),
+    dict(type='ObjectSample', db_sampler=db_sampler),
+    dict(type='RandomFlip3D', flip_ratio_bev_horizontal=0.5),
+    dict(
+        type='ObjectNoise',
+        num_try=100,
+        translation_std=[1.0, 1.0, 0],
+        global_rot_range=[0.0, 0.0],
+        rot_range=[-1.0471975511965976, 1.0471975511965976]),
+    dict(
+        type='GlobalRotScaleTrans',
+        rot_range=[-0.78539816, 0.78539816],
+        scale_ratio_range=[0.9, 1.1]),
+    dict(type='BackgroundPointsFilter', bbox_enlarge_range=(0.5, 2.0, 0.5)),
+    dict(type='IndoorPointSample', num_points=16384),
+    dict(type='DefaultFormatBundle3D', class_names=class_names),
+    dict(type='Collect3D', keys=['points', 'gt_bboxes_3d', 'gt_labels_3d'])
+]
+
+test_pipeline = [
+    dict(
+        type='LoadPointsFromFile',
+        load_dim=4,
+        use_dim=4,
+        file_client_args=file_client_args),
+    dict(
+        type='MultiScaleFlipAug3D',
+        img_scale=(1333, 800),
+        pts_scale_ratio=1,
+        flip=False,
+        transforms=[
+            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='IndoorPointSample', num_points=16384),
+            dict(
+                type='DefaultFormatBundle3D',
+                class_names=class_names,
+                with_label=False),
+            dict(type='Collect3D', keys=['points'])
+        ])
+]
+
+data = dict(
+    samples_per_gpu=4,
+    workers_per_gpu=4,
+    train=dict(dataset=dict(pipeline=train_pipeline)),
+    val=dict(pipeline=test_pipeline),
+    test=dict(pipeline=test_pipeline))
+
+evaluation = dict(interval=2)
+
+# model settings
+model = dict(
+    bbox_head=dict(
+        num_classes=1,
+        bbox_coder=dict(
+            type='AnchorFreeBBoxCoder', num_dir_bins=12, with_rot=True)))
+
+# optimizer
+lr = 0.002  # max learning rate
+optimizer = dict(type='AdamW', lr=lr, weight_decay=0)
+optimizer_config = dict(grad_clip=dict(max_norm=35, norm_type=2))
+lr_config = dict(policy='step', warmup=None, step=[80, 120])
+# runtime settings
+total_epochs = 150
+
+# yapf:disable
+log_config = dict(
+    interval=30,
+    hooks=[
+        dict(type='TextLoggerHook'),
+        dict(type='TensorboardLoggerHook')
+    ])
+# yapf:enable

configs/_base_/models/3dssd.py

+model = dict(
+    type='SSD3DNet',
+    backbone=dict(
+        type='PointNet2SAMSG',
+        in_channels=4,
+        num_points=(4096, 512, (256, 256)),
+        radii=((0.2, 0.4, 0.8), (0.4, 0.8, 1.6), (1.6, 3.2, 4.8)),
+        num_samples=((32, 32, 64), (32, 32, 64), (32, 32, 32)),
+        sa_channels=(((16, 16, 32), (16, 16, 32), (32, 32, 64)),
+                     ((64, 64, 128), (64, 64, 128), (64, 96, 128)),
+                     ((128, 128, 256), (128, 192, 256), (128, 256, 256))),
+        aggregation_channels=(64, 128, 256),
+        fps_mods=(('D-FPS'), ('FS'), ('F-FPS', 'D-FPS')),
+        fps_sample_range_lists=((-1), (-1), (512, -1)),
+        norm_cfg=dict(type='BN2d', eps=1e-3, momentum=0.1),
+        sa_cfg=dict(
+            type='PointSAModuleMSG',
+            pool_mod='max',
+            use_xyz=True,
+            normalize_xyz=False)),
+    bbox_head=dict(
+        type='SSD3DHead',
+        in_channels=256,
+        vote_module_cfg=dict(
+            in_channels=256,
+            num_points=256,
+            gt_per_seed=1,
+            conv_channels=(128, ),
+            conv_cfg=dict(type='Conv1d'),
+            norm_cfg=dict(type='BN1d', eps=1e-3, momentum=0.1),
+            with_res_feat=False,
+            vote_xyz_range=(3.0, 3.0, 2.0)),
+        vote_aggregation_cfg=dict(
+            type='PointSAModuleMSG',
+            num_point=256,
+            radii=(4.8, 6.4),
+            sample_nums=(16, 32),
+            mlp_channels=((256, 256, 256, 512), (256, 256, 512, 1024)),
+            norm_cfg=dict(type='BN2d', eps=1e-3, momentum=0.1),
+            use_xyz=True,
+            normalize_xyz=False,
+            bias=True),
+        pred_layer_cfg=dict(
+            in_channels=1536,
+            shared_conv_channels=(512, 128),
+            cls_conv_layers=(128, ),
+            reg_conv_layers=(128, ),
+            conv_cfg=dict(type='Conv1d'),
+            norm_cfg=dict(type='BN1d', eps=1e-3, momentum=0.1),
+            bias=True),
+        conv_cfg=dict(type='Conv1d'),
+        norm_cfg=dict(type='BN1d', eps=1e-3, momentum=0.1),
+        objectness_loss=dict(
+            type='CrossEntropyLoss',
+            use_sigmoid=True,
+            reduction='sum',
+            loss_weight=1.0),
+        center_loss=dict(
+            type='SmoothL1Loss', reduction='sum', loss_weight=1.0),
+        dir_class_loss=dict(
+            type='CrossEntropyLoss', reduction='sum', loss_weight=1.0),
+        dir_res_loss=dict(
+            type='SmoothL1Loss', reduction='sum', loss_weight=1.0),
+        size_res_loss=dict(
+            type='SmoothL1Loss', reduction='sum', loss_weight=1.0),
+        corner_loss=dict(
+            type='SmoothL1Loss', reduction='sum', loss_weight=1.0),
+        vote_loss=dict(type='SmoothL1Loss', reduction='sum', loss_weight=1.0)))
+
+# model training and testing settings
+train_cfg = dict(
+    sample_mod='spec', pos_distance_thr=10.0, expand_dims_length=0.05)
+test_cfg = dict(
+    nms_cfg=dict(type='nms', iou_thr=0.1),
+    sample_mod='spec',
+    score_thr=0.0,
+    per_class_proposal=True,
+    max_output_num=100)
+
+# optimizer
+# This schedule is mainly used by models on indoor dataset,
+# e.g., VoteNet on SUNRGBD and ScanNet
+lr = 0.002  # max learning rate
+optimizer = dict(type='AdamW', lr=lr, weight_decay=0)
+optimizer_config = dict(grad_clip=dict(max_norm=35, norm_type=2))
+lr_config = dict(policy='step', warmup=None, step=[80, 120])
+# runtime settings
+total_epochs = 150

configs/_base_/models/h3dnet.py

@@ -5,7 +5,7 @@ primitive_z_cfg = dict(
     primitive_mode='z',
     upper_thresh=100.0,
     surface_thresh=0.5,
-    vote_moudule_cfg=dict(
+    vote_module_cfg=dict(
         in_channels=256,
         vote_per_seed=1,
         gt_per_seed=1,
@@ -63,7 +63,7 @@ primitive_xy_cfg = dict(
     primitive_mode='xy',
     upper_thresh=100.0,
     surface_thresh=0.5,
-    vote_moudule_cfg=dict(
+    vote_module_cfg=dict(
         in_channels=256,
         vote_per_seed=1,
         gt_per_seed=1,
@@ -121,7 +121,7 @@ primitive_line_cfg = dict(
     primitive_mode='line',
     upper_thresh=100.0,
     surface_thresh=0.5,
-    vote_moudule_cfg=dict(
+    vote_module_cfg=dict(
         in_channels=256,
         vote_per_seed=1,
         gt_per_seed=1,
@@ -198,7 +198,7 @@ model = dict(
                 normalize_xyz=True))),
     rpn_head=dict(
         type='VoteHead',
-        vote_moudule_cfg=dict(
+        vote_module_cfg=dict(
             in_channels=256,
             vote_per_seed=1,
             gt_per_seed=3,
@@ -219,7 +219,7 @@ model = dict(
             mlp_channels=[256, 128, 128, 128],
             use_xyz=True,
             normalize_xyz=True),
-        feat_channels=(128, 128),
+        pred_layer_cfg=dict(in_channels=128, shared_conv_channels=(128, 128)),
         conv_cfg=dict(type='Conv1d'),
         norm_cfg=dict(type='BN1d'),
         objectness_loss=dict(

configs/_base_/models/votenet.py

@@ -17,7 +17,7 @@ model = dict(
             normalize_xyz=True)),
     bbox_head=dict(
         type='VoteHead',
-        vote_moudule_cfg=dict(
+        vote_module_cfg=dict(
             in_channels=256,
             vote_per_seed=1,
             gt_per_seed=3,
@@ -38,7 +38,7 @@ model = dict(
             mlp_channels=[256, 128, 128, 128],
             use_xyz=True,
             normalize_xyz=True),
-        feat_channels=(128, 128),
+        pred_layer_cfg=dict(in_channels=128, shared_conv_channels=(128, 128)),
         conv_cfg=dict(type='Conv1d'),
         norm_cfg=dict(type='BN1d'),
         objectness_loss=dict(

mmdet3d/core/bbox/coders/__init__.py

 from mmdet.core.bbox import build_bbox_coder
+from .anchor_free_bbox_coder import AnchorFreeBBoxCoder
 from .delta_xyzwhlr_bbox_coder import DeltaXYZWLHRBBoxCoder
 from .partial_bin_based_bbox_coder import PartialBinBasedBBoxCoder
 
 __all__ = [
-    'build_bbox_coder', 'DeltaXYZWLHRBBoxCoder', 'PartialBinBasedBBoxCoder'
+    'build_bbox_coder', 'DeltaXYZWLHRBBoxCoder', 'PartialBinBasedBBoxCoder',
+    'AnchorFreeBBoxCoder'
 ]

mmdet3d/core/bbox/coders/anchor_free_bbox_coder.py

+import numpy as np
+import torch
+
+from mmdet.core.bbox.builder import BBOX_CODERS
+from .partial_bin_based_bbox_coder import PartialBinBasedBBoxCoder
+
+
+@BBOX_CODERS.register_module()
+class AnchorFreeBBoxCoder(PartialBinBasedBBoxCoder):
+    """Anchor free bbox coder for 3D boxes.
+
+    Args:
+        num_dir_bins (int): Number of bins to encode direction angle.
+        with_rot (bool): Whether the bbox is with rotation.
+    """
+
+    def __init__(self, num_dir_bins, with_rot=True):
+        super(AnchorFreeBBoxCoder, self).__init__(
+            num_dir_bins, 0, [], with_rot=with_rot)
+        self.num_dir_bins = num_dir_bins
+        self.with_rot = with_rot
+
+    def encode(self, gt_bboxes_3d, gt_labels_3d):
+        """Encode ground truth to prediction targets.
+
+        Args:
+            gt_bboxes_3d (BaseInstance3DBoxes): Ground truth bboxes \
+                with shape (n, 7).
+            gt_labels_3d (torch.Tensor): Ground truth classes.
+
+        Returns:
+            tuple: Targets of center, size and direction.
+        """
+        # generate center target
+        center_target = gt_bboxes_3d.gravity_center
+
+        # generate bbox size target
+        size_res_target = gt_bboxes_3d.dims / 2
+
+        # generate dir target
+        box_num = gt_labels_3d.shape[0]
+        if self.with_rot:
+            (dir_class_target,
+             dir_res_target) = self.angle2class(gt_bboxes_3d.yaw)
+            dir_res_target /= (2 * np.pi / self.num_dir_bins)
+        else:
+            dir_class_target = gt_labels_3d.new_zeros(box_num)
+            dir_res_target = gt_bboxes_3d.tensor.new_zeros(box_num)
+
+        return (center_target, size_res_target, dir_class_target,
+                dir_res_target)
+
+    def decode(self, bbox_out):
+        """Decode predicted parts to bbox3d.
+
+        Args:
+            bbox_out (dict): Predictions from model, should contain keys below.
+
+                - center: predicted bottom center of bboxes.
+                - dir_class: predicted bbox direction class.
+                - dir_res: predicted bbox direction residual.
+                - size: predicted bbox size.
+
+        Returns:
+            torch.Tensor: Decoded bbox3d with shape (batch, n, 7).
+        """
+        center = bbox_out['center']
+        batch_size, num_proposal = center.shape[:2]
+
+        # decode heading angle
+        if self.with_rot:
+            dir_class = torch.argmax(bbox_out['dir_class'], -1)
+            dir_res = torch.gather(bbox_out['dir_res'], 2,
+                                   dir_class.unsqueeze(-1))
+            dir_res.squeeze_(2)
+            dir_angle = self.class2angle(dir_class, dir_res).reshape(
+                batch_size, num_proposal, 1)
+        else:
+            dir_angle = center.new_zeros(batch_size, num_proposal, 1)
+
+        # decode bbox size
+        bbox_size = torch.clamp(bbox_out['size'] * 2, min=0.1)
+
+        bbox3d = torch.cat([center, bbox_size, dir_angle], dim=-1)
+        return bbox3d
+
+    def split_pred(self, cls_preds, reg_preds, base_xyz):
+        """Split predicted features to specific parts.
+
+        Args:
+            cls_preds (torch.Tensor): Class predicted features to split.
+            reg_preds (torch.Tensor): Regression predicted features to split.
+            base_xyz (torch.Tensor): Coordinates of points.
+
+        Returns:
+            dict[str, torch.Tensor]: Split results.
+        """
+        results = {}
+        results['obj_scores'] = cls_preds
+
+        start, end = 0, 0
+        reg_preds_trans = reg_preds.transpose(2, 1)
+
+        # decode center
+        end += 3
+        # (batch_size, num_proposal, 3)
+        results['center_offset'] = reg_preds_trans[..., start:end]
+        results['center'] = base_xyz.detach() + reg_preds_trans[..., start:end]
+        start = end
+
+        # decode center
+        end += 3
+        # (batch_size, num_proposal, 3)
+        results['size'] = reg_preds_trans[..., start:end]
+        start = end
+
+        # decode direction
+        end += self.num_dir_bins
+        results['dir_class'] = reg_preds_trans[..., start:end]
+        start = end
+
+        end += self.num_dir_bins
+        dir_res_norm = reg_preds_trans[..., start:end]
+        start = end
+
+        results['dir_res_norm'] = dir_res_norm
+        results['dir_res'] = dir_res_norm * (2 * np.pi / self.num_dir_bins)
+
+        return results

mmdet3d/core/bbox/coders/partial_bin_based_bbox_coder.py

@@ -98,11 +98,12 @@ class PartialBinBasedBBoxCoder(BaseBBoxCoder):
         bbox3d = torch.cat([center, bbox_size, dir_angle], dim=-1)
         return bbox3d
 
-    def split_pred(self, preds, base_xyz):
+    def split_pred(self, cls_preds, reg_preds, base_xyz):
         """Split predicted features to specific parts.
 
         Args:
-            preds (torch.Tensor): Predicted features to split.
+            cls_preds (torch.Tensor): Class predicted features to split.
+            reg_preds (torch.Tensor): Regression predicted features to split.
             base_xyz (torch.Tensor): Coordinates of points.
 
         Returns:
@@ -110,26 +111,24 @@ class PartialBinBasedBBoxCoder(BaseBBoxCoder):
         """
         results = {}
         start, end = 0, 0
-        preds_trans = preds.transpose(2, 1)
 
-        # decode objectness score
-        end += 2
-        results['obj_scores'] = preds_trans[..., start:end].contiguous()
-        start = end
+        cls_preds_trans = cls_preds.transpose(2, 1)
+        reg_preds_trans = reg_preds.transpose(2, 1)
 
         # decode center
         end += 3
         # (batch_size, num_proposal, 3)
-        results['center'] = base_xyz + preds_trans[..., start:end].contiguous()
+        results['center'] = base_xyz + \
+            reg_preds_trans[..., start:end].contiguous()
         start = end
 
         # decode direction
         end += self.num_dir_bins
-        results['dir_class'] = preds_trans[..., start:end].contiguous()
+        results['dir_class'] = reg_preds_trans[..., start:end].contiguous()
         start = end
 
         end += self.num_dir_bins
-        dir_res_norm = preds_trans[..., start:end].contiguous()
+        dir_res_norm = reg_preds_trans[..., start:end].contiguous()
         start = end
 
         results['dir_res_norm'] = dir_res_norm
@@ -137,23 +136,29 @@ class PartialBinBasedBBoxCoder(BaseBBoxCoder):
 
         # decode size
         end += self.num_sizes
-        results['size_class'] = preds_trans[..., start:end].contiguous()
+        results['size_class'] = reg_preds_trans[..., start:end].contiguous()
         start = end
 
         end += self.num_sizes * 3
-        size_res_norm = preds_trans[..., start:end]
-        batch_size, num_proposal = preds_trans.shape[:2]
+        size_res_norm = reg_preds_trans[..., start:end]
+        batch_size, num_proposal = reg_preds_trans.shape[:2]
         size_res_norm = size_res_norm.view(
             [batch_size, num_proposal, self.num_sizes, 3])
         start = end
 
         results['size_res_norm'] = size_res_norm.contiguous()
-        mean_sizes = preds.new_tensor(self.mean_sizes)
+        mean_sizes = reg_preds.new_tensor(self.mean_sizes)
         results['size_res'] = (
             size_res_norm * mean_sizes.unsqueeze(0).unsqueeze(0))
 
+        # decode objectness score
+        start = 0
+        end = 2
+        results['obj_scores'] = cls_preds_trans[..., start:end].contiguous()
+        start = end
+
         # decode semantic score
-        results['sem_scores'] = preds_trans[..., start:].contiguous()
+        results['sem_scores'] = cls_preds_trans[..., start:].contiguous()
 
         return results
 

mmdet3d/core/bbox/structures/depth_box3d.py

@@ -252,6 +252,21 @@ class DepthInstance3DBoxes(BaseInstance3DBoxes):
 
         return box_idxs_of_pts.squeeze(0)
 
+    def enlarged_box(self, extra_width):
+        """Enlarge the length, width and height boxes.
+
+        Args:
+            extra_width (float | torch.Tensor): Extra width to enlarge the box.
+
+        Returns:
+            :obj:`LiDARInstance3DBoxes`: Enlarged boxes.
+        """
+        enlarged_boxes = self.tensor.clone()
+        enlarged_boxes[:, 3:6] += extra_width * 2
+        # bottom center z minus extra_width
+        enlarged_boxes[:, 2] -= extra_width
+        return self.new_box(enlarged_boxes)
+
     def get_surface_line_center(self):
         """Compute surface and line center of bounding boxes.
 

mmdet3d/core/evaluation/kitti_utils/eval.py

@@ -475,6 +475,7 @@ def eval_class(gt_annos,
     if num_examples < num_parts:
         num_parts = num_examples
     split_parts = get_split_parts(num_examples, num_parts)
+
     rets = calculate_iou_partly(dt_annos, gt_annos, metric, num_parts)
     overlaps, parted_overlaps, total_dt_num, total_gt_num = rets
     N_SAMPLE_PTS = 41

mmdet3d/models/backbones/pointnet2_sa_msg.py

@@ -24,6 +24,7 @@ class PointNet2SAMSG(BasePointNet):
         fps_mods (tuple[int]): Mod of FPS for each SA module.
         fps_sample_range_lists (tuple[tuple[int]]): The number of sampling
             points which each SA module samples.
+        dilated_group (tuple[bool]): Whether to use dilated ball query for
         out_indices (Sequence[int]): Output from which stages.
         norm_cfg (dict): Config of normalization layer.
         sa_cfg (dict): Config of set abstraction module, which may contain
@@ -47,13 +48,14 @@ class PointNet2SAMSG(BasePointNet):
                  aggregation_channels=(64, 128, 256),
                  fps_mods=(('D-FPS'), ('FS'), ('F-FPS', 'D-FPS')),
                  fps_sample_range_lists=((-1), (-1), (512, -1)),
+                 dilated_group=(True, True, True),
                  out_indices=(2, ),
                  norm_cfg=dict(type='BN2d'),
                  sa_cfg=dict(
                      type='PointSAModuleMSG',
                      pool_mod='max',
                      use_xyz=True,
-                     normalize_xyz=True)):
+                     normalize_xyz=False)):
         super().__init__()
         self.num_sa = len(sa_channels)
         self.out_indices = out_indices
@@ -94,6 +96,7 @@ class PointNet2SAMSG(BasePointNet):
                     mlp_channels=cur_sa_mlps,
                     fps_mod=cur_fps_mod,
                     fps_sample_range_list=cur_fps_sample_range_list,
+                    dilated_group=dilated_group[sa_index],
                     norm_cfg=norm_cfg,
                     cfg=sa_cfg,
                     bias=True))
@@ -137,6 +140,7 @@ class PointNet2SAMSG(BasePointNet):
         out_sa_xyz = []
         out_sa_features = []
         out_sa_indices = []
+
         for i in range(self.num_sa):
             cur_xyz, cur_features, cur_indices = self.SA_modules[i](
                 sa_xyz[i], sa_features[i])

mmdet3d/models/dense_heads/__init__.py

 from .anchor3d_head import Anchor3DHead
+from .base_conv_bbox_head import BaseConvBboxHead
 from .free_anchor3d_head import FreeAnchor3DHead
 from .parta2_rpn_head import PartA2RPNHead
+from .ssd_3d_head import SSD3DHead
 from .vote_head import VoteHead
 
-__all__ = ['Anchor3DHead', 'FreeAnchor3DHead', 'PartA2RPNHead', 'VoteHead']
+__all__ = [
+    'Anchor3DHead', 'FreeAnchor3DHead', 'PartA2RPNHead', 'VoteHead',
+    'SSD3DHead', 'BaseConvBboxHead'
+]

mmdet3d/models/dense_heads/base_conv_bbox_head.py

+from mmcv.cnn import ConvModule
+from mmcv.cnn.bricks import build_conv_layer
+from torch import nn as nn
+
+from mmdet.models.builder import HEADS
+
+
+@HEADS.register_module()
+class BaseConvBboxHead(nn.Module):
+    r"""More general bbox head, with shared conv layers and two optional
+    separated branches.
+
+    .. code-block:: none
+
+                     /-> cls convs -> cls_score
+        shared convs
+                     \-> reg convs -> bbox_pred
+    """
+
+    def __init__(self,
+                 in_channels=0,
+                 shared_conv_channels=(),
+                 cls_conv_channels=(),
+                 num_cls_out_channels=0,
+                 reg_conv_channels=(),
+                 num_reg_out_channels=0,
+                 conv_cfg=dict(type='Conv1d'),
+                 norm_cfg=dict(type='BN1d'),
+                 act_cfg=dict(type='ReLU'),
+                 bias='auto',
+                 *args,
+                 **kwargs):
+        super(BaseConvBboxHead, self).__init__(*args, **kwargs)
+        assert in_channels > 0
+        assert num_cls_out_channels > 0
+        assert num_reg_out_channels > 0
+        self.in_channels = in_channels
+        self.shared_conv_channels = shared_conv_channels
+        self.cls_conv_channels = cls_conv_channels
+        self.num_cls_out_channels = num_cls_out_channels
+        self.reg_conv_channels = reg_conv_channels
+        self.num_reg_out_channels = num_reg_out_channels
+        self.conv_cfg = conv_cfg
+        self.norm_cfg = norm_cfg
+        self.act_cfg = act_cfg
+        self.bias = bias
+
+        # add shared convs
+        if len(self.shared_conv_channels) > 0:
+            self.shared_convs = self._add_conv_branch(
+                self.in_channels, self.shared_conv_channels)
+            out_channels = self.shared_conv_channels[-1]
+        else:
+            out_channels = self.in_channels
+
+        # add cls specific branch
+        prev_channel = out_channels
+        if len(self.cls_conv_channels) > 0:
+            self.cls_convs = self._add_conv_branch(prev_channel,
+                                                   self.cls_conv_channels)
+            prev_channel = self.cls_conv_channels[-1]
+
+        self.conv_cls = build_conv_layer(
+            conv_cfg,
+            in_channels=prev_channel,
+            out_channels=num_cls_out_channels,
+            kernel_size=1)
+        # add reg specific branch
+        prev_channel = out_channels
+        if len(self.reg_conv_channels) > 0:
+            self.reg_convs = self._add_conv_branch(prev_channel,
+                                                   self.reg_conv_channels)
+            prev_channel = self.reg_conv_channels[-1]
+
+        self.conv_reg = build_conv_layer(
+            conv_cfg,
+            in_channels=prev_channel,
+            out_channels=num_reg_out_channels,
+            kernel_size=1)
+
+    def _add_conv_branch(self, in_channels, conv_channels):
+        """Add shared or separable branch."""
+        conv_spec = [in_channels] + list(conv_channels)
+        # add branch specific conv layers
+        conv_layers = nn.Sequential()
+        for i in range(len(conv_spec) - 1):
+            conv_layers.add_module(
+                f'layer{i}',
+                ConvModule(
+                    conv_spec[i],
+                    conv_spec[i + 1],
+                    kernel_size=1,
+                    padding=0,
+                    conv_cfg=self.conv_cfg,
+                    norm_cfg=self.norm_cfg,
+                    act_cfg=self.act_cfg,
+                    bias=self.bias,
+                    inplace=True))
+        return conv_layers
+
+    def init_weights(self):
+        # conv layers are already initialized by ConvModule
+        pass
+
+    def forward(self, feats):
+        """Forward.
+
+        Args:
+            feats (Tensor): Input features
+
+        Returns:
+            Tensor: Class scores predictions
+            Tensor: Regression predictions
+        """
+        # shared part
+        if len(self.shared_conv_channels) > 0:
+            x = self.shared_convs(feats)
+
+        # separate branches
+        x_cls = x
+        x_reg = x
+
+        if len(self.cls_conv_channels) > 0:
+            x_cls = self.cls_convs(x_cls)
+        cls_score = self.conv_cls(x_cls)
+
+        if len(self.reg_conv_channels) > 0:
+            x_reg = self.reg_convs(x_reg)
+        bbox_pred = self.conv_reg(x_reg)
+
+        return cls_score, bbox_pred

mmdet3d/models/dense_heads/vote_head.py

 import numpy as np
 import torch
-from mmcv.cnn import ConvModule
 from torch import nn as nn
 from torch.nn import functional as F
 
@@ -11,6 +10,7 @@ from mmdet3d.models.model_utils import VoteModule
 from mmdet3d.ops import build_sa_module, furthest_point_sample
 from mmdet.core import build_bbox_coder, multi_apply
 from mmdet.models import HEADS
+from .base_conv_bbox_head import BaseConvBboxHead
 
 
 @HEADS.register_module()
@@ -23,10 +23,10 @@ class VoteHead(nn.Module):
             decoding boxes.
         train_cfg (dict): Config for training.
         test_cfg (dict): Config for testing.
-        vote_moudule_cfg (dict): Config of VoteModule for point-wise votes.
+        vote_module_cfg (dict): Config of VoteModule for point-wise votes.
         vote_aggregation_cfg (dict): Config of vote aggregation layer.
-        feat_channels (tuple[int]): Convolution channels of
-            prediction layer.
+        pred_layer_cfg (dict): Config of classfication and regression
+            prediction layers.
         conv_cfg (dict): Config of convolution in prediction layer.
         norm_cfg (dict): Config of BN in prediction layer.
         objectness_loss (dict): Config of objectness loss.
@@ -43,9 +43,9 @@ class VoteHead(nn.Module):
                  bbox_coder,
                  train_cfg=None,
                  test_cfg=None,
-                 vote_moudule_cfg=None,
+                 vote_module_cfg=None,
                  vote_aggregation_cfg=None,
-                 feat_channels=(128, 128),
+                 pred_layer_cfg=None,
                  conv_cfg=dict(type='Conv1d'),
                  norm_cfg=dict(type='BN1d'),
                  objectness_loss=None,
@@ -59,54 +59,64 @@ class VoteHead(nn.Module):
         self.num_classes = num_classes
         self.train_cfg = train_cfg
         self.test_cfg = test_cfg
-        self.gt_per_seed = vote_moudule_cfg['gt_per_seed']
+        self.gt_per_seed = vote_module_cfg['gt_per_seed']
         self.num_proposal = vote_aggregation_cfg['num_point']
 
         self.objectness_loss = build_loss(objectness_loss)
         self.center_loss = build_loss(center_loss)
-        self.dir_class_loss = build_loss(dir_class_loss)
         self.dir_res_loss = build_loss(dir_res_loss)
-        self.size_class_loss = build_loss(size_class_loss)
+        self.dir_class_loss = build_loss(dir_class_loss)
         self.size_res_loss = build_loss(size_res_loss)
-        self.semantic_loss = build_loss(semantic_loss)
-
-        assert vote_aggregation_cfg['mlp_channels'][0] == vote_moudule_cfg[
-            'in_channels']
+        if size_class_loss is not None:
+            self.size_class_loss = build_loss(size_class_loss)
+        if semantic_loss is not None:
+            self.semantic_loss = build_loss(semantic_loss)
 
         self.bbox_coder = build_bbox_coder(bbox_coder)
         self.num_sizes = self.bbox_coder.num_sizes
         self.num_dir_bins = self.bbox_coder.num_dir_bins
 
-        self.vote_module = VoteModule(**vote_moudule_cfg)
+        self.vote_module = VoteModule(**vote_module_cfg)
         self.vote_aggregation = build_sa_module(vote_aggregation_cfg)
 
-        prev_channel = vote_aggregation_cfg['mlp_channels'][-1]
-        conv_pred_list = list()
-        for k in range(len(feat_channels)):
-            conv_pred_list.append(
-                ConvModule(
-                    prev_channel,
-                    feat_channels[k],
-                    1,
-                    padding=0,
-                    conv_cfg=conv_cfg,
-                    norm_cfg=norm_cfg,
-                    bias=True,
-                    inplace=True))
-            prev_channel = feat_channels[k]
-        self.conv_pred = nn.Sequential(*conv_pred_list)
+        # Bbox classification and regression
+        self.conv_pred = BaseConvBboxHead(
+            **pred_layer_cfg,
+            num_cls_out_channels=self._get_cls_out_channels(),
+            num_reg_out_channels=self._get_reg_out_channels())
+
+    def init_weights(self):
+        """Initialize weights of VoteHead."""
+        pass
 
+    def _get_cls_out_channels(self):
+        """Return the channel number of classification outputs."""
+        # Class numbers (k) + objectness (2)
+        return self.num_classes + 2
+
+    def _get_reg_out_channels(self):
+        """Return the channel number of regression outputs."""
         # Objectness scores (2), center residual (3),
         # heading class+residual (num_dir_bins*2),
         # size class+residual(num_sizes*4)
-        conv_out_channel = (2 + 3 + self.num_dir_bins * 2 +
-                            self.num_sizes * 4 + num_classes)
-        self.conv_pred.add_module('conv_out',
-                                  nn.Conv1d(prev_channel, conv_out_channel, 1))
+        return 3 + self.num_dir_bins * 2 + self.num_sizes * 4
 
-    def init_weights(self):
-        """Initialize weights of VoteHead."""
-        pass
+    def _extract_input(self, feat_dict):
+        """Extract inputs from features dictionary.
+
+        Args:
+            feat_dict (dict): Feature dict from backbone.
+
+        Returns:
+            torch.Tensor: Coordinates of input points.
+            torch.Tensor: Features of input points.
+            torch.Tensor: Indices of input points.
+        """
+        seed_points = feat_dict['fp_xyz'][-1]
+        seed_features = feat_dict['fp_features'][-1]
+        seed_indices = feat_dict['fp_indices'][-1]
+
+        return seed_points, seed_features, seed_indices
 
     def forward(self, feat_dict, sample_mod):
         """Forward pass.
@@ -122,57 +132,74 @@ class VoteHead(nn.Module):
         Args:
             feat_dict (dict): Feature dict from backbone.
             sample_mod (str): Sample mode for vote aggregation layer.
-                valid modes are "vote", "seed" and "random".
+                valid modes are "vote", "seed", "random" and "spec".
 
         Returns:
             dict: Predictions of vote head.
         """
-        assert sample_mod in ['vote', 'seed', 'random']
+        assert sample_mod in ['vote', 'seed', 'random', 'spec']
 
-        seed_points = feat_dict['fp_xyz'][-1]
-        seed_features = feat_dict['fp_features'][-1]
-        seed_indices = feat_dict['fp_indices'][-1]
+        seed_points, seed_features, seed_indices = self._extract_input(
+            feat_dict)
 
         # 1. generate vote_points from seed_points
-        vote_points, vote_features = self.vote_module(seed_points,
-                                                      seed_features)
+        vote_points, vote_features, vote_offset = self.vote_module(
+            seed_points, seed_features)
         results = dict(
             seed_points=seed_points,
             seed_indices=seed_indices,
             vote_points=vote_points,
-            vote_features=vote_features)
+            vote_features=vote_features,
+            vote_offset=vote_offset)
 
         # 2. aggregate vote_points
         if sample_mod == 'vote':
             # use fps in vote_aggregation
-            sample_indices = None
+            aggregation_inputs = dict(
+                points_xyz=vote_points, features=vote_features)
         elif sample_mod == 'seed':
             # FPS on seed and choose the votes corresponding to the seeds
             sample_indices = furthest_point_sample(seed_points,
                                                    self.num_proposal)
+            aggregation_inputs = dict(
+                points_xyz=vote_points,
+                features=vote_features,
+                indices=sample_indices)
         elif sample_mod == 'random':
             # Random sampling from the votes
             batch_size, num_seed = seed_points.shape[:2]
             sample_indices = seed_points.new_tensor(
                 torch.randint(0, num_seed, (batch_size, self.num_proposal)),
                 dtype=torch.int32)
+            aggregation_inputs = dict(
+                points_xyz=vote_points,
+                features=vote_features,
+                indices=sample_indices)
+        elif sample_mod == 'spec':
+            # Specify the new center in vote_aggregation
+            aggregation_inputs = dict(
+                points_xyz=seed_points,
+                features=seed_features,
+                target_xyz=vote_points)
         else:
             raise NotImplementedError(
                 f'Sample mode {sample_mod} is not supported!')
 
-        vote_aggregation_ret = self.vote_aggregation(vote_points,
-                                                     vote_features,
-                                                     sample_indices)
+        vote_aggregation_ret = self.vote_aggregation(**aggregation_inputs)
         aggregated_points, features, aggregated_indices = vote_aggregation_ret
+
         results['aggregated_points'] = aggregated_points
         results['aggregated_features'] = features
         results['aggregated_indices'] = aggregated_indices
 
         # 3. predict bbox and score
-        predictions = self.conv_pred(features)
+        cls_predictions, reg_predictions = self.conv_pred(features)
 
         # 4. decode predictions
-        decode_res = self.bbox_coder.split_pred(predictions, aggregated_points)
+        decode_res = self.bbox_coder.split_pred(cls_predictions,
+                                                reg_predictions,
+                                                aggregated_points)
+
         results.update(decode_res)
 
         return results

mmdet3d/models/detectors/__init__.py

@@ -4,10 +4,12 @@ from .h3dnet import H3DNet
 from .mvx_faster_rcnn import DynamicMVXFasterRCNN, MVXFasterRCNN
 from .mvx_two_stage import MVXTwoStageDetector
 from .parta2 import PartA2
+from .ssd3dnet import SSD3DNet
 from .votenet import VoteNet
 from .voxelnet import VoxelNet
 
 __all__ = [
     'Base3DDetector', 'VoxelNet', 'DynamicVoxelNet', 'MVXTwoStageDetector',
-    'DynamicMVXFasterRCNN', 'MVXFasterRCNN', 'PartA2', 'VoteNet', 'H3DNet'
+    'DynamicMVXFasterRCNN', 'MVXFasterRCNN', 'PartA2', 'VoteNet', 'H3DNet',
+    'SSD3DNet'
 ]

mmdet3d/models/detectors/ssd3dnet.py

+from mmdet.models import DETECTORS
+from .votenet import VoteNet
+
+
+@DETECTORS.register_module()
+class SSD3DNet(VoteNet):
+    """3DSSDNet model.
+
+    https://arxiv.org/abs/2002.10187.pdf
+    """
+
+    def __init__(self,
+                 backbone,
+                 bbox_head=None,
+                 train_cfg=None,
+                 test_cfg=None,
+                 pretrained=None):
+        super(SSD3DNet, self).__init__(
+            backbone=backbone,
+            bbox_head=bbox_head,
+            train_cfg=train_cfg,
+            test_cfg=test_cfg,
+            pretrained=pretrained)

mmdet3d/models/model_utils/vote_module.py

 import torch
+from mmcv import is_tuple_of
 from mmcv.cnn import ConvModule
 from torch import nn as nn
 
@@ -15,6 +16,7 @@ class VoteModule(nn.Module):
         vote_per_seed (int): Number of votes generated from each seed point.
         gt_per_seed (int): Number of ground truth votes generated
             from each seed point.
+        num_points (int): Number of points to be used for voting.
         conv_channels (tuple[int]): Out channels of vote
             generating convolution.
         conv_cfg (dict): Config of convolution.
@@ -23,6 +25,9 @@ class VoteModule(nn.Module):
             Default: dict(type='BN1d').
         norm_feats (bool): Whether to normalize features.
             Default: True.
+        with_res_feat (bool): Whether to predict residual features.
+            Default: True.
+        vote_xyz_range (list[float], None): The range of points translation.
         vote_loss (dict): Config of vote loss.
     """
 
@@ -30,17 +35,28 @@ class VoteModule(nn.Module):
                  in_channels,
                  vote_per_seed=1,
                  gt_per_seed=3,
+                 num_points=-1,
                  conv_channels=(16, 16),
                  conv_cfg=dict(type='Conv1d'),
                  norm_cfg=dict(type='BN1d'),
+                 act_cfg=dict(type='ReLU'),
                  norm_feats=True,
+                 with_res_feat=True,
+                 vote_xyz_range=None,
                  vote_loss=None):
         super().__init__()
         self.in_channels = in_channels
         self.vote_per_seed = vote_per_seed
         self.gt_per_seed = gt_per_seed
+        self.num_points = num_points
         self.norm_feats = norm_feats
-        self.vote_loss = build_loss(vote_loss)
+        self.with_res_feat = with_res_feat
+
+        assert vote_xyz_range is None or is_tuple_of(vote_xyz_range, float)
+        self.vote_xyz_range = vote_xyz_range
+
+        if vote_loss is not None:
+            self.vote_loss = build_loss(vote_loss)
 
         prev_channels = in_channels
         vote_conv_list = list()
@@ -53,13 +69,17 @@ class VoteModule(nn.Module):
                     padding=0,
                     conv_cfg=conv_cfg,
                     norm_cfg=norm_cfg,
+                    act_cfg=act_cfg,
                     bias=True,
                     inplace=True))
             prev_channels = conv_channels[k]
         self.vote_conv = nn.Sequential(*vote_conv_list)
 
         # conv_out predicts coordinate and residual features
-        out_channel = (3 + in_channels) * self.vote_per_seed
+        if with_res_feat:
+            out_channel = (3 + in_channels) * self.vote_per_seed
+        else:
+            out_channel = 3 * self.vote_per_seed
         self.conv_out = nn.Conv1d(prev_channels, out_channel, 1)
 
     def forward(self, seed_points, seed_feats):
@@ -80,6 +100,13 @@ class VoteModule(nn.Module):
                     shape (B, C, M) where ``M=num_seed*vote_per_seed``, \
                     ``C=vote_feature_dim``.
         """
+        if self.num_points != -1:
+            assert self.num_points < seed_points.shape[1], \
+                f'Number of vote points ({self.num_points}) should be '\
+                f'smaller than seed points size ({seed_points.shape[1]})'
+            seed_points = seed_points[:, :self.num_points]
+            seed_feats = seed_feats[..., :self.num_points]
+
         batch_size, feat_channels, num_seed = seed_feats.shape
         num_vote = num_seed * self.vote_per_seed
         x = self.vote_conv(seed_feats)
@@ -88,21 +115,36 @@ class VoteModule(nn.Module):
 
         votes = votes.transpose(2, 1).view(batch_size, num_seed,
                                            self.vote_per_seed, -1)
-        offset = votes[:, :, :, 0:3].contiguous()
-        res_feats = votes[:, :, :, 3:].contiguous()
 
-        vote_points = seed_points.unsqueeze(2) + offset
+        offset = votes[:, :, :, 0:3]
+        if self.vote_xyz_range is not None:
+            limited_offset_list = []
+            for axis in range(len(self.vote_xyz_range)):
+                limited_offset_list.append(offset[..., axis].clamp(
+                    min=-self.vote_xyz_range[axis],
+                    max=self.vote_xyz_range[axis]))
+            limited_offset = torch.stack(limited_offset_list, -1)
+            vote_points = (seed_points.unsqueeze(2) +
+                           limited_offset).contiguous()
+        else:
+            vote_points = (seed_points.unsqueeze(2) + offset).contiguous()
         vote_points = vote_points.view(batch_size, num_vote, 3)
-        vote_feats = seed_feats.permute(
-            0, 2, 1).unsqueeze(2).contiguous() + res_feats
-        vote_feats = vote_feats.view(batch_size, num_vote,
-                                     feat_channels).transpose(2,
-                                                              1).contiguous()
-
-        if self.norm_feats:
-            features_norm = torch.norm(vote_feats, p=2, dim=1)
-            vote_feats = vote_feats.div(features_norm.unsqueeze(1))
-        return vote_points, vote_feats
+        offset = offset.reshape(batch_size, num_vote, 3).transpose(2, 1)
+
+        if self.with_res_feat:
+            res_feats = votes[:, :, :, 3:]
+            vote_feats = (seed_feats.transpose(2, 1).unsqueeze(2) +
+                          res_feats).contiguous()
+            vote_feats = vote_feats.view(batch_size,
+                                         num_vote, feat_channels).transpose(
+                                             2, 1).contiguous()
+
+            if self.norm_feats:
+                features_norm = torch.norm(vote_feats, p=2, dim=1)
+                vote_feats = vote_feats.div(features_norm.unsqueeze(1))
+        else:
+            vote_feats = seed_feats
+        return vote_points, vote_feats, offset
 
     def get_loss(self, seed_points, vote_points, seed_indices,
                  vote_targets_mask, vote_targets):

mmdet3d/models/roi_heads/bbox_heads/h3d_bbox_head.py

@@ -308,8 +308,9 @@ class H3DBboxHead(nn.Module):
         for conv_module in self.bbox_pred[1:]:
             bbox_predictions = conv_module(bbox_predictions)
 
-        refine_decode_res = self.bbox_coder.split_pred(bbox_predictions,
-                                                       aggregated_points)
+        refine_decode_res = self.bbox_coder.split_pred(
+            bbox_predictions[:, :self.num_classes + 2],
+            bbox_predictions[:, self.num_classes + 2:], aggregated_points)
         for key in refine_decode_res.keys():
             ret_dict[key + '_optimized'] = refine_decode_res[key]
         return ret_dict

mmdet3d/models/roi_heads/mask_heads/primitive_head.py

@@ -23,7 +23,7 @@ class PrimitiveHead(nn.Module):
             decoding boxes.
         train_cfg (dict): Config for training.
         test_cfg (dict): Config for testing.
-        vote_moudule_cfg (dict): Config of VoteModule for point-wise votes.
+        vote_module_cfg (dict): Config of VoteModule for point-wise votes.
         vote_aggregation_cfg (dict): Config of vote aggregation layer.
         feat_channels (tuple[int]): Convolution channels of
             prediction layer.
@@ -42,7 +42,7 @@ class PrimitiveHead(nn.Module):
                  primitive_mode,
                  train_cfg=None,
                  test_cfg=None,
-                 vote_moudule_cfg=None,
+                 vote_module_cfg=None,
                  vote_aggregation_cfg=None,
                  feat_channels=(128, 128),
                  upper_thresh=100.0,
@@ -61,7 +61,7 @@ class PrimitiveHead(nn.Module):
         self.primitive_mode = primitive_mode
         self.train_cfg = train_cfg
         self.test_cfg = test_cfg
-        self.gt_per_seed = vote_moudule_cfg['gt_per_seed']
+        self.gt_per_seed = vote_module_cfg['gt_per_seed']
         self.num_proposal = vote_aggregation_cfg['num_point']
         self.upper_thresh = upper_thresh
         self.surface_thresh = surface_thresh
@@ -71,13 +71,13 @@ class PrimitiveHead(nn.Module):
         self.semantic_reg_loss = build_loss(semantic_reg_loss)
         self.semantic_cls_loss = build_loss(semantic_cls_loss)
 
-        assert vote_aggregation_cfg['mlp_channels'][0] == vote_moudule_cfg[
+        assert vote_aggregation_cfg['mlp_channels'][0] == vote_module_cfg[
             'in_channels']
 
         # Primitive existence flag prediction
         self.flag_conv = ConvModule(
-            vote_moudule_cfg['conv_channels'][-1],
-            vote_moudule_cfg['conv_channels'][-1] // 2,
+            vote_module_cfg['conv_channels'][-1],
+            vote_module_cfg['conv_channels'][-1] // 2,
             1,
             padding=0,
             conv_cfg=conv_cfg,
@@ -85,9 +85,9 @@ class PrimitiveHead(nn.Module):
             bias=True,
             inplace=True)
         self.flag_pred = torch.nn.Conv1d(
-            vote_moudule_cfg['conv_channels'][-1] // 2, 2, 1)
+            vote_module_cfg['conv_channels'][-1] // 2, 2, 1)
 
-        self.vote_module = VoteModule(**vote_moudule_cfg)
+        self.vote_module = VoteModule(**vote_module_cfg)
         self.vote_aggregation = build_sa_module(vote_aggregation_cfg)
 
         prev_channel = vote_aggregation_cfg['mlp_channels'][-1]
@@ -137,8 +137,8 @@ class PrimitiveHead(nn.Module):
         results['pred_flag_' + self.primitive_mode] = primitive_flag
 
         # 1. generate vote_points from seed_points
-        vote_points, vote_features = self.vote_module(seed_points,
-                                                      seed_features)
+        vote_points, vote_features, _ = self.vote_module(
+            seed_points, seed_features)
         results['vote_' + self.primitive_mode] = vote_points
         results['vote_features_' + self.primitive_mode] = vote_features
 

tests/test_box_coders.py

 import torch
 
-from mmdet3d.core.bbox import DepthInstance3DBoxes
+from mmdet3d.core.bbox import DepthInstance3DBoxes, LiDARInstance3DBoxes
 from mmdet.core import build_bbox_coder
 
 
@@ -194,9 +194,10 @@ def test_partial_bin_based_box_coder():
     assert torch.allclose(bbox3d, expected_bbox3d, atol=1e-4)
 
     # test split_pred
-    box_preds = torch.rand(2, 79, 256)
+    cls_preds = torch.rand(2, 12, 256)
+    reg_preds = torch.rand(2, 67, 256)
     base_xyz = torch.rand(2, 256, 3)
-    results = box_coder.split_pred(box_preds, base_xyz)
+    results = box_coder.split_pred(cls_preds, reg_preds, base_xyz)
     obj_scores = results['obj_scores']
     center = results['center']
     dir_class = results['dir_class']
@@ -215,3 +216,110 @@ def test_partial_bin_based_box_coder():
     assert size_res_norm.shape == torch.Size([2, 256, 10, 3])
     assert size_res.shape == torch.Size([2, 256, 10, 3])
     assert sem_scores.shape == torch.Size([2, 256, 10])
+
+
+def test_anchor_free_box_coder():
+    box_coder_cfg = dict(
+        type='AnchorFreeBBoxCoder', num_dir_bins=12, with_rot=True)
+    box_coder = build_bbox_coder(box_coder_cfg)
+
+    # test encode
+    gt_bboxes = LiDARInstance3DBoxes([[
+        2.1227e+00, 5.7951e+00, -9.9900e-01, 1.6736e+00, 4.2419e+00,
+        1.5473e+00, -1.5501e+00
+    ],
+                                      [
+                                          1.1791e+01, 9.0276e+00, -8.5772e-01,
+                                          1.6210e+00, 3.5367e+00, 1.4841e+00,
+                                          -1.7369e+00
+                                      ],
+                                      [
+                                          2.3638e+01, 9.6997e+00, -5.6713e-01,
+                                          1.7578e+00, 4.6103e+00, 1.5999e+00,
+                                          -1.4556e+00
+                                      ]])
+    gt_labels = torch.tensor([0, 0, 0])
+
+    (center_targets, size_targets, dir_class_targets,
+     dir_res_targets) = box_coder.encode(gt_bboxes, gt_labels)
+
+    expected_center_target = torch.tensor([[2.1227, 5.7951, -0.2253],
+                                           [11.7908, 9.0276, -0.1156],
+                                           [23.6380, 9.6997, 0.2328]])
+    expected_size_targets = torch.tensor([[0.8368, 2.1210, 0.7736],
+                                          [0.8105, 1.7683, 0.7421],
+                                          [0.8789, 2.3052, 0.8000]])
+    expected_dir_class_target = torch.tensor([9, 9, 9])
+    expected_dir_res_target = torch.tensor([0.0394, -0.3172, 0.2199])
+    assert torch.allclose(center_targets, expected_center_target, atol=1e-4)
+    assert torch.allclose(size_targets, expected_size_targets, atol=1e-4)
+    assert torch.all(dir_class_targets == expected_dir_class_target)
+    assert torch.allclose(dir_res_targets, expected_dir_res_target, atol=1e-3)
+
+    # test decode
+    center = torch.tensor([[[14.5954, 6.3312, 0.7671],
+                            [67.5245, 22.4422, 1.5610],
+                            [47.7693, -6.7980, 1.4395]]])
+
+    size_res = torch.tensor([[[-1.0752, 1.8760, 0.7715],
+                              [-0.8016, 1.1754, 0.0102],
+                              [-1.2789, 0.5948, 0.4728]]])
+
+    dir_class = torch.tensor([[[
+        0.1512, 1.7914, -1.7658, 2.1572, -0.9215, 1.2139, 0.1749, 0.8606,
+        1.1743, -0.7679, -1.6005, 0.4623
+    ],
+                               [
+                                   -0.3957, 1.2026, -1.2677, 1.3863, -0.5754,
+                                   1.7083, 0.2601, 0.1129, 0.7146, -0.1367,
+                                   -1.2892, -0.0083
+                               ],
+                               [
+                                   -0.8862, 1.2050, -1.3881, 1.6604, -0.9087,
+                                   1.1907, -0.0280, 0.2027, 1.0644, -0.7205,
+                                   -1.0738, 0.4748
+                               ]]])
+
+    dir_res = torch.tensor([[[
+        1.1151, 0.5535, -0.2053, -0.6582, -0.1616, -0.1821, 0.4675, 0.6621,
+        0.8146, -0.0448, -0.7253, -0.7171
+    ],
+                             [
+                                 0.7888, 0.2478, -0.1962, -0.7267, 0.0573,
+                                 -0.2398, 0.6984, 0.5859, 0.7507, -0.1980,
+                                 -0.6538, -0.6602
+                             ],
+                             [
+                                 0.9039, 0.6109, 0.1960, -0.5016, 0.0551,
+                                 -0.4086, 0.3398, 0.2759, 0.7247, -0.0655,
+                                 -0.5052, -0.9026
+                             ]]])
+    bbox_out = dict(
+        center=center, size=size_res, dir_class=dir_class, dir_res=dir_res)
+
+    bbox3d = box_coder.decode(bbox_out)
+    expected_bbox3d = torch.tensor(
+        [[[14.5954, 6.3312, 0.7671, 0.1000, 3.7521, 1.5429, 0.9126],
+          [67.5245, 22.4422, 1.5610, 0.1000, 2.3508, 0.1000, 2.3782],
+          [47.7693, -6.7980, 1.4395, 0.1000, 1.1897, 0.9456, 1.0692]]])
+    assert torch.allclose(bbox3d, expected_bbox3d, atol=1e-4)
+
+    # test split_pred
+    cls_preds = torch.rand(2, 1, 256)
+    reg_preds = torch.rand(2, 30, 256)
+    base_xyz = torch.rand(2, 256, 3)
+    results = box_coder.split_pred(cls_preds, reg_preds, base_xyz)
+    obj_scores = results['obj_scores']
+    center = results['center']
+    center_offset = results['center_offset']
+    dir_class = results['dir_class']
+    dir_res_norm = results['dir_res_norm']
+    dir_res = results['dir_res']
+    size = results['size']
+    assert obj_scores.shape == torch.Size([2, 1, 256])
+    assert center.shape == torch.Size([2, 256, 3])
+    assert center_offset.shape == torch.Size([2, 256, 3])
+    assert dir_class.shape == torch.Size([2, 256, 12])
+    assert dir_res_norm.shape == torch.Size([2, 256, 12])
+    assert dir_res.shape == torch.Size([2, 256, 12])
+    assert size.shape == torch.Size([2, 256, 3])