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| # Copyright (c) OpenMMLab. All rights reserved. | |
| import torch | |
| from torch import nn as nn | |
| from torch.autograd import Function | |
| import annotator.mmpkg.mmcv as mmcv | |
| from ..utils import ext_loader | |
| ext_module = ext_loader.load_ext( | |
| '_ext', ['roiaware_pool3d_forward', 'roiaware_pool3d_backward']) | |
| class RoIAwarePool3d(nn.Module): | |
| """Encode the geometry-specific features of each 3D proposal. | |
| Please refer to `PartA2 <https://arxiv.org/pdf/1907.03670.pdf>`_ for more | |
| details. | |
| Args: | |
| out_size (int or tuple): The size of output features. n or | |
| [n1, n2, n3]. | |
| max_pts_per_voxel (int, optional): The maximum number of points per | |
| voxel. Default: 128. | |
| mode (str, optional): Pooling method of RoIAware, 'max' or 'avg'. | |
| Default: 'max'. | |
| """ | |
| def __init__(self, out_size, max_pts_per_voxel=128, mode='max'): | |
| super().__init__() | |
| self.out_size = out_size | |
| self.max_pts_per_voxel = max_pts_per_voxel | |
| assert mode in ['max', 'avg'] | |
| pool_mapping = {'max': 0, 'avg': 1} | |
| self.mode = pool_mapping[mode] | |
| def forward(self, rois, pts, pts_feature): | |
| """ | |
| Args: | |
| rois (torch.Tensor): [N, 7], in LiDAR coordinate, | |
| (x, y, z) is the bottom center of rois. | |
| pts (torch.Tensor): [npoints, 3], coordinates of input points. | |
| pts_feature (torch.Tensor): [npoints, C], features of input points. | |
| Returns: | |
| pooled_features (torch.Tensor): [N, out_x, out_y, out_z, C] | |
| """ | |
| return RoIAwarePool3dFunction.apply(rois, pts, pts_feature, | |
| self.out_size, | |
| self.max_pts_per_voxel, self.mode) | |
| class RoIAwarePool3dFunction(Function): | |
| def forward(ctx, rois, pts, pts_feature, out_size, max_pts_per_voxel, | |
| mode): | |
| """ | |
| Args: | |
| rois (torch.Tensor): [N, 7], in LiDAR coordinate, | |
| (x, y, z) is the bottom center of rois. | |
| pts (torch.Tensor): [npoints, 3], coordinates of input points. | |
| pts_feature (torch.Tensor): [npoints, C], features of input points. | |
| out_size (int or tuple): The size of output features. n or | |
| [n1, n2, n3]. | |
| max_pts_per_voxel (int): The maximum number of points per voxel. | |
| Default: 128. | |
| mode (int): Pooling method of RoIAware, 0 (max pool) or 1 (average | |
| pool). | |
| Returns: | |
| pooled_features (torch.Tensor): [N, out_x, out_y, out_z, C], output | |
| pooled features. | |
| """ | |
| if isinstance(out_size, int): | |
| out_x = out_y = out_z = out_size | |
| else: | |
| assert len(out_size) == 3 | |
| assert mmcv.is_tuple_of(out_size, int) | |
| out_x, out_y, out_z = out_size | |
| num_rois = rois.shape[0] | |
| num_channels = pts_feature.shape[-1] | |
| num_pts = pts.shape[0] | |
| pooled_features = pts_feature.new_zeros( | |
| (num_rois, out_x, out_y, out_z, num_channels)) | |
| argmax = pts_feature.new_zeros( | |
| (num_rois, out_x, out_y, out_z, num_channels), dtype=torch.int) | |
| pts_idx_of_voxels = pts_feature.new_zeros( | |
| (num_rois, out_x, out_y, out_z, max_pts_per_voxel), | |
| dtype=torch.int) | |
| ext_module.roiaware_pool3d_forward(rois, pts, pts_feature, argmax, | |
| pts_idx_of_voxels, pooled_features, | |
| mode) | |
| ctx.roiaware_pool3d_for_backward = (pts_idx_of_voxels, argmax, mode, | |
| num_pts, num_channels) | |
| return pooled_features | |
| def backward(ctx, grad_out): | |
| ret = ctx.roiaware_pool3d_for_backward | |
| pts_idx_of_voxels, argmax, mode, num_pts, num_channels = ret | |
| grad_in = grad_out.new_zeros((num_pts, num_channels)) | |
| ext_module.roiaware_pool3d_backward(pts_idx_of_voxels, argmax, | |
| grad_out.contiguous(), grad_in, | |
| mode) | |
| return None, None, grad_in, None, None, None | |