Robert001's picture
first commit
b334e29
raw
history blame
No virus
4.1 kB
import mmcv
import torch
from mmcv.runner import load_checkpoint
from .. import build_detector
from ..builder import DETECTORS
from .single_stage import SingleStageDetector
@DETECTORS.register_module()
class KnowledgeDistillationSingleStageDetector(SingleStageDetector):
r"""Implementation of `Distilling the Knowledge in a Neural Network.
<https://arxiv.org/abs/1503.02531>`_.
Args:
teacher_config (str | dict): Config file path
or the config object of teacher model.
teacher_ckpt (str, optional): Checkpoint path of teacher model.
If left as None, the model will not load any weights.
"""
def __init__(self,
backbone,
neck,
bbox_head,
teacher_config,
teacher_ckpt=None,
eval_teacher=True,
train_cfg=None,
test_cfg=None,
pretrained=None):
super().__init__(backbone, neck, bbox_head, train_cfg, test_cfg,
pretrained)
self.eval_teacher = eval_teacher
# Build teacher model
if isinstance(teacher_config, str):
teacher_config = mmcv.Config.fromfile(teacher_config)
self.teacher_model = build_detector(teacher_config['model'])
if teacher_ckpt is not None:
load_checkpoint(
self.teacher_model, teacher_ckpt, map_location='cpu')
def forward_train(self,
img,
img_metas,
gt_bboxes,
gt_labels,
gt_bboxes_ignore=None):
"""
Args:
img (Tensor): Input images of shape (N, C, H, W).
Typically these should be mean centered and std scaled.
img_metas (list[dict]): A List of image info dict where each dict
has: 'img_shape', 'scale_factor', 'flip', and may also contain
'filename', 'ori_shape', 'pad_shape', and 'img_norm_cfg'.
For details on the values of these keys see
:class:`mmdet.datasets.pipelines.Collect`.
gt_bboxes (list[Tensor]): Each item are the truth boxes for each
image in [tl_x, tl_y, br_x, br_y] format.
gt_labels (list[Tensor]): Class indices corresponding to each box
gt_bboxes_ignore (None | list[Tensor]): Specify which bounding
boxes can be ignored when computing the loss.
Returns:
dict[str, Tensor]: A dictionary of loss components.
"""
x = self.extract_feat(img)
with torch.no_grad():
teacher_x = self.teacher_model.extract_feat(img)
out_teacher = self.teacher_model.bbox_head(teacher_x)
losses = self.bbox_head.forward_train(x, out_teacher, img_metas,
gt_bboxes, gt_labels,
gt_bboxes_ignore)
return losses
def cuda(self, device=None):
"""Since teacher_model is registered as a plain object, it is necessary
to put the teacher model to cuda when calling cuda function."""
self.teacher_model.cuda(device=device)
return super().cuda(device=device)
def train(self, mode=True):
"""Set the same train mode for teacher and student model."""
if self.eval_teacher:
self.teacher_model.train(False)
else:
self.teacher_model.train(mode)
super().train(mode)
def __setattr__(self, name, value):
"""Set attribute, i.e. self.name = value
This reloading prevent the teacher model from being registered as a
nn.Module. The teacher module is registered as a plain object, so that
the teacher parameters will not show up when calling
``self.parameters``, ``self.modules``, ``self.children`` methods.
"""
if name == 'teacher_model':
object.__setattr__(self, name, value)
else:
super().__setattr__(name, value)