ktda-models / ktda /models /segmentors /distill_encoder_decoder.py
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# Copyright (c) OpenMMLab. All rights reserved.
import logging
from typing import List, Optional
import torch.nn as nn
import torch.nn.functional as F
from mmengine.logging import print_log
from torch import Tensor
from mmseg.registry import MODELS
from mmseg.utils import (
ConfigType,
OptConfigType,
OptMultiConfig,
OptSampleList,
SampleList,
add_prefix,
)
from mmseg.models import BaseSegmentor
@MODELS.register_module()
class DistillEncoderDecoder(BaseSegmentor):
def __init__(
self,
backbone: ConfigType,
teach_backbone: ConfigType,
decode_head: ConfigType,
neck: OptConfigType = None,
auxiliary_head: OptConfigType = None,
fam: OptConfigType = None,
fmm: OptConfigType = None,
train_cfg: OptConfigType = None,
test_cfg: OptConfigType = None,
data_preprocessor: OptConfigType = None,
pretrained: Optional[str] = None,
student_training=True,
temperature=1.0,
alpha=0.5,
fuse=False,
init_cfg: OptMultiConfig = None,
):
super().__init__(data_preprocessor=data_preprocessor, init_cfg=init_cfg)
self.temperature = temperature
self.alpha = alpha
self.student_training = student_training
self.fuse = fuse
if pretrained is not None:
assert (
backbone.get("pretrained") is None
), "both backbone and segmentor set pretrained weight"
assert (
teach_backbone.get("pretrained") is None
), "both teach backbone and segmentor set pretrained weight"
backbone.pretrained = pretrained
teach_backbone.pretrained = pretrained
self.backbone = MODELS.build(backbone)
self.teach_backbone = MODELS.build(teach_backbone)
if neck is not None:
self.neck = MODELS.build(neck)
self.fam = nn.Identity()
self.fmm = nn.Identity()
if fam is not None:
self.fam = MODELS.build(fam)
if fmm is not None:
self.fmm = MODELS.build(fmm)
self._init_decode_head(decode_head)
self._init_auxiliary_head(auxiliary_head)
self.train_cfg = train_cfg
self.test_cfg = test_cfg
assert self.with_decode_head
def _init_decode_head(self, decode_head: ConfigType) -> None:
"""Initialize ``decode_head``"""
self.decode_head = MODELS.build(decode_head)
self.align_corners = self.decode_head.align_corners
self.num_classes = self.decode_head.num_classes
self.out_channels = self.decode_head.out_channels
def _init_auxiliary_head(self, auxiliary_head: ConfigType) -> None:
"""Initialize ``auxiliary_head``"""
if auxiliary_head is not None:
if isinstance(auxiliary_head, list):
self.auxiliary_head = nn.ModuleList()
for head_cfg in auxiliary_head:
self.auxiliary_head.append(MODELS.build(head_cfg))
else:
self.auxiliary_head = MODELS.build(auxiliary_head)
def fuse_features(self,features):
x = features[0]
for index,feature in enumerate(features):
if index == 0:
continue
x += feature
x = [x]
return tuple(x)
def extract_feat(self, inputs: Tensor) -> List[Tensor]:
"""Extract features from images."""
x = self.backbone(inputs)
x = self.fam(x)
if self.fuse:
x = self.fuse_features(x)
if self.with_neck:
x = self.neck(x)
x = self.fmm(x)
return x
def encode_decode(self, inputs: Tensor, batch_img_metas: List[dict]) -> Tensor:
"""Encode images with backbone and decode into a semantic segmentation
map of the same size as input."""
x = self.extract_feat(inputs)
seg_logits = self.decode_head.predict(x, batch_img_metas, self.test_cfg)
return seg_logits
def _decode_head_forward_train(
self, inputs: List[Tensor], data_samples: SampleList
) -> dict:
"""Run forward function and calculate loss for decode head in
training."""
losses = dict()
loss_decode = self.decode_head.loss(inputs, data_samples, self.train_cfg)
losses.update(add_prefix(loss_decode, "decode"))
return losses
def _auxiliary_head_forward_train(
self, inputs: List[Tensor], data_samples: SampleList
) -> dict:
"""Run forward function and calculate loss for auxiliary head in
training."""
losses = dict()
if isinstance(self.auxiliary_head, nn.ModuleList):
for idx, aux_head in enumerate(self.auxiliary_head):
loss_aux = aux_head.loss(inputs, data_samples, self.train_cfg)
for key in loss_aux.keys():
loss_aux[key] = loss_aux[key] / len(self.auxiliary_head)
losses.update(add_prefix(loss_aux, f"aux_{idx}"))
else:
loss_aux = self.auxiliary_head.loss(inputs, data_samples, self.train_cfg)
losses.update(add_prefix(loss_aux, "aux"))
return losses
def calculate_diltill_loss(self, inputs):
student_feats = self.backbone(inputs)
student_feats = self.fam(student_feats)
teach_feats = self.teach_backbone(inputs)
if self.fuse:
student_feats = self.fuse_features(student_feats)
teach_feats = self.fuse_features(teach_feats)
total_loss = 0.0
for student_feat, teach_feat in zip(student_feats, teach_feats):
student_prob = F.softmax(student_feat / self.temperature, dim=-1)
teach_prob = F.softmax(teach_feat / self.temperature, dim=-1)
kl_loss = F.kl_div(
student_prob.log(), teach_prob, reduction="batchmean"
) * (self.temperature**2)
mse_loss = F.mse_loss(student_feat, teach_feat, reduction="mean")
loss = self.alpha * kl_loss + (1 - self.alpha) * mse_loss
total_loss += loss
avg_loss = total_loss / len(student_feats)
if self.alpha == 0:
avg_loss = avg_loss * 0.5
return avg_loss
def loss(self, inputs: Tensor, data_samples: SampleList) -> dict:
"""Calculate losses from a batch of inputs and data samples.
Args:
inputs (Tensor): Input images.
data_samples (list[:obj:`SegDataSample`]): The seg data samples.
It usually includes information such as `metainfo` and
`gt_sem_seg`.
Returns:
dict[str, Tensor]: a dictionary of loss components
"""
x = self.extract_feat(inputs)
losses = dict()
loss_decode = self._decode_head_forward_train(x, data_samples)
losses.update(loss_decode)
if self.student_training:
losses["distill_loss"] = self.calculate_diltill_loss(inputs)
if self.with_auxiliary_head:
loss_aux = self._auxiliary_head_forward_train(x, data_samples)
losses.update(loss_aux)
return losses
def predict(self, inputs: Tensor, data_samples: OptSampleList = None) -> SampleList:
"""Predict results from a batch of inputs and data samples with post-
processing.
Args:
inputs (Tensor): Inputs with shape (N, C, H, W).
data_samples (List[:obj:`SegDataSample`], optional): The seg data
samples. It usually includes information such as `metainfo`
and `gt_sem_seg`.
Returns:
list[:obj:`SegDataSample`]: Segmentation results of the
input images. Each SegDataSample usually contain:
- ``pred_sem_seg``(PixelData): Prediction of semantic segmentation.
- ``seg_logits``(PixelData): Predicted logits of semantic
segmentation before normalization.
"""
if data_samples is not None:
batch_img_metas = [data_sample.metainfo for data_sample in data_samples]
else:
batch_img_metas = [
dict(
ori_shape=inputs.shape[2:],
img_shape=inputs.shape[2:],
pad_shape=inputs.shape[2:],
padding_size=[0, 0, 0, 0],
)
] * inputs.shape[0]
seg_logits = self.inference(inputs, batch_img_metas)
return self.postprocess_result(seg_logits, data_samples)
def _forward(self, inputs: Tensor, data_samples: OptSampleList = None) -> Tensor:
"""Network forward process.
Args:
inputs (Tensor): Inputs with shape (N, C, H, W).
data_samples (List[:obj:`SegDataSample`]): The seg
data samples. It usually includes information such
as `metainfo` and `gt_sem_seg`.
Returns:
Tensor: Forward output of model without any post-processes.
"""
x = self.extract_feat(inputs)
return self.decode_head.forward(x)
def slide_inference(self, inputs: Tensor, batch_img_metas: List[dict]) -> Tensor:
"""Inference by sliding-window with overlap.
If h_crop > h_img or w_crop > w_img, the small patch will be used to
decode without padding.
Args:
inputs (tensor): the tensor should have a shape NxCxHxW,
which contains all images in the batch.
batch_img_metas (List[dict]): List of image metainfo where each may
also contain: 'img_shape', 'scale_factor', 'flip', 'img_path',
'ori_shape', and 'pad_shape'.
For details on the values of these keys see
`mmseg/datasets/pipelines/formatting.py:PackSegInputs`.
Returns:
Tensor: The segmentation results, seg_logits from model of each
input image.
"""
h_stride, w_stride = self.test_cfg.stride
h_crop, w_crop = self.test_cfg.crop_size
batch_size, _, h_img, w_img = inputs.size()
out_channels = self.out_channels
h_grids = max(h_img - h_crop + h_stride - 1, 0) // h_stride + 1
w_grids = max(w_img - w_crop + w_stride - 1, 0) // w_stride + 1
preds = inputs.new_zeros((batch_size, out_channels, h_img, w_img))
count_mat = inputs.new_zeros((batch_size, 1, h_img, w_img))
for h_idx in range(h_grids):
for w_idx in range(w_grids):
y1 = h_idx * h_stride
x1 = w_idx * w_stride
y2 = min(y1 + h_crop, h_img)
x2 = min(x1 + w_crop, w_img)
y1 = max(y2 - h_crop, 0)
x1 = max(x2 - w_crop, 0)
crop_img = inputs[:, :, y1:y2, x1:x2]
# change the image shape to patch shape
batch_img_metas[0]["img_shape"] = crop_img.shape[2:]
# the output of encode_decode is seg logits tensor map
# with shape [N, C, H, W]
crop_seg_logit = self.encode_decode(crop_img, batch_img_metas)
preds += F.pad(
crop_seg_logit,
(
int(x1),
int(preds.shape[3] - x2),
int(y1),
int(preds.shape[2] - y2),
),
)
count_mat[:, :, y1:y2, x1:x2] += 1
assert (count_mat == 0).sum() == 0
seg_logits = preds / count_mat
return seg_logits
def whole_inference(self, inputs: Tensor, batch_img_metas: List[dict]) -> Tensor:
"""Inference with full image.
Args:
inputs (Tensor): The tensor should have a shape NxCxHxW, which
contains all images in the batch.
batch_img_metas (List[dict]): List of image metainfo where each may
also contain: 'img_shape', 'scale_factor', 'flip', 'img_path',
'ori_shape', and 'pad_shape'.
For details on the values of these keys see
`mmseg/datasets/pipelines/formatting.py:PackSegInputs`.
Returns:
Tensor: The segmentation results, seg_logits from model of each
input image.
"""
seg_logits = self.encode_decode(inputs, batch_img_metas)
return seg_logits
def inference(self, inputs: Tensor, batch_img_metas: List[dict]) -> Tensor:
"""Inference with slide/whole style.
Args:
inputs (Tensor): The input image of shape (N, 3, H, W).
batch_img_metas (List[dict]): List of image metainfo where each may
also contain: 'img_shape', 'scale_factor', 'flip', 'img_path',
'ori_shape', 'pad_shape', and 'padding_size'.
For details on the values of these keys see
`mmseg/datasets/pipelines/formatting.py:PackSegInputs`.
Returns:
Tensor: The segmentation results, seg_logits from model of each
input image.
"""
assert self.test_cfg.get("mode", "whole") in ["slide", "whole"], (
f'Only "slide" or "whole" test mode are supported, but got '
f'{self.test_cfg["mode"]}.'
)
ori_shape = batch_img_metas[0]["ori_shape"]
if not all(_["ori_shape"] == ori_shape for _ in batch_img_metas):
print_log(
"Image shapes are different in the batch.",
logger="current",
level=logging.WARN,
)
if self.test_cfg.mode == "slide":
seg_logit = self.slide_inference(inputs, batch_img_metas)
else:
seg_logit = self.whole_inference(inputs, batch_img_metas)
return seg_logit
def aug_test(self, inputs, batch_img_metas, rescale=True):
"""Test with augmentations.
Only rescale=True is supported.
"""
# aug_test rescale all imgs back to ori_shape for now
assert rescale
# to save memory, we get augmented seg logit inplace
seg_logit = self.inference(inputs[0], batch_img_metas[0], rescale)
for i in range(1, len(inputs)):
cur_seg_logit = self.inference(inputs[i], batch_img_metas[i], rescale)
seg_logit += cur_seg_logit
seg_logit /= len(inputs)
seg_pred = seg_logit.argmax(dim=1)
# unravel batch dim
seg_pred = list(seg_pred)
return seg_pred