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mmcls.models.utils.data_preprocessor 源代码

# Copyright (c) OpenMMLab. All rights reserved.
import math
from numbers import Number
from typing import Optional, Sequence

import torch
import torch.nn.functional as F
from mmengine.model import BaseDataPreprocessor, stack_batch

from mmcls.registry import MODELS
from mmcls.structures import (ClsDataSample, MultiTaskDataSample,
                              batch_label_to_onehot, cat_batch_labels,
                              stack_batch_scores, tensor_split)
from .batch_augments import RandomBatchAugment


[文档]@MODELS.register_module() class ClsDataPreprocessor(BaseDataPreprocessor): """Image pre-processor for classification tasks. Comparing with the :class:`mmengine.model.ImgDataPreprocessor`, 1. It won't do normalization if ``mean`` is not specified. 2. It does normalization and color space conversion after stacking batch. 3. It supports batch augmentations like mixup and cutmix. It provides the data pre-processing as follows - Collate and move data to the target device. - Pad inputs to the maximum size of current batch with defined ``pad_value``. The padding size can be divisible by a defined ``pad_size_divisor`` - Stack inputs to batch_inputs. - Convert inputs from bgr to rgb if the shape of input is (3, H, W). - Normalize image with defined std and mean. - Do batch augmentations like Mixup and Cutmix during training. Args: mean (Sequence[Number], optional): The pixel mean of R, G, B channels. Defaults to None. std (Sequence[Number], optional): The pixel standard deviation of R, G, B channels. Defaults to None. pad_size_divisor (int): The size of padded image should be divisible by ``pad_size_divisor``. Defaults to 1. pad_value (Number): The padded pixel value. Defaults to 0. to_rgb (bool): whether to convert image from BGR to RGB. Defaults to False. to_onehot (bool): Whether to generate one-hot format gt-labels and set to data samples. Defaults to False. num_classes (int, optional): The number of classes. Defaults to None. batch_augments (dict, optional): The batch augmentations settings, including "augments" and "probs". For more details, see :class:`mmcls.models.RandomBatchAugment`. """ def __init__(self, mean: Sequence[Number] = None, std: Sequence[Number] = None, pad_size_divisor: int = 1, pad_value: Number = 0, to_rgb: bool = False, to_onehot: bool = False, num_classes: Optional[int] = None, batch_augments: Optional[dict] = None): super().__init__() self.pad_size_divisor = pad_size_divisor self.pad_value = pad_value self.to_rgb = to_rgb self.to_onehot = to_onehot self.num_classes = num_classes if mean is not None: assert std is not None, 'To enable the normalization in ' \ 'preprocessing, please specify both `mean` and `std`.' # Enable the normalization in preprocessing. self._enable_normalize = True self.register_buffer('mean', torch.tensor(mean).view(-1, 1, 1), False) self.register_buffer('std', torch.tensor(std).view(-1, 1, 1), False) else: self._enable_normalize = False if batch_augments is not None: self.batch_augments = RandomBatchAugment(**batch_augments) if not self.to_onehot: from mmengine.logging import MMLogger MMLogger.get_current_instance().info( 'Because batch augmentations are enabled, the data ' 'preprocessor automatically enables the `to_onehot` ' 'option to generate one-hot format labels.') self.to_onehot = True else: self.batch_augments = None
[文档] def forward(self, data: dict, training: bool = False) -> dict: """Perform normalization, padding, bgr2rgb conversion and batch augmentation based on ``BaseDataPreprocessor``. Args: data (dict): data sampled from dataloader. training (bool): Whether to enable training time augmentation. Returns: dict: Data in the same format as the model input. """ inputs = self.cast_data(data['inputs']) if isinstance(inputs, torch.Tensor): # The branch if use `default_collate` as the collate_fn in the # dataloader. # ------ To RGB ------ if self.to_rgb and inputs.size(1) == 3: inputs = inputs.flip(1) # -- Normalization --- inputs = inputs.float() if self._enable_normalize: inputs = (inputs - self.mean) / self.std # ------ Padding ----- if self.pad_size_divisor > 1: h, w = inputs.shape[-2:] target_h = math.ceil( h / self.pad_size_divisor) * self.pad_size_divisor target_w = math.ceil( w / self.pad_size_divisor) * self.pad_size_divisor pad_h = target_h - h pad_w = target_w - w inputs = F.pad(inputs, (0, pad_w, 0, pad_h), 'constant', self.pad_value) else: # The branch if use `pseudo_collate` as the collate_fn in the # dataloader. processed_inputs = [] for input_ in inputs: # ------ To RGB ------ if self.to_rgb and input_.size(0) == 3: input_ = input_.flip(0) # -- Normalization --- input_ = input_.float() if self._enable_normalize: input_ = (input_ - self.mean) / self.std processed_inputs.append(input_) # Combine padding and stack inputs = stack_batch(processed_inputs, self.pad_size_divisor, self.pad_value) data_samples = data.get('data_samples', None) sample_item = data_samples[0] if data_samples is not None else None if isinstance(sample_item, ClsDataSample) and 'gt_label' in sample_item: gt_labels = [sample.gt_label for sample in data_samples] batch_label, label_indices = cat_batch_labels( gt_labels, device=self.device) batch_score = stack_batch_scores(gt_labels, device=self.device) if batch_score is None and self.to_onehot: assert batch_label is not None, \ 'Cannot generate onehot format labels because no labels.' num_classes = self.num_classes or data_samples[0].get( 'num_classes') assert num_classes is not None, \ 'Cannot generate one-hot format labels because not set ' \ '`num_classes` in `data_preprocessor`.' batch_score = batch_label_to_onehot(batch_label, label_indices, num_classes) # ----- Batch Augmentations ---- if training and self.batch_augments is not None: inputs, batch_score = self.batch_augments(inputs, batch_score) # ----- scatter labels and scores to data samples --- if batch_label is not None: for sample, label in zip( data_samples, tensor_split(batch_label, label_indices)): sample.set_gt_label(label) if batch_score is not None: for sample, score in zip(data_samples, batch_score): sample.set_gt_score(score) elif isinstance(sample_item, MultiTaskDataSample): data_samples = self.cast_data(data_samples) return {'inputs': inputs, 'data_samples': data_samples}
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