diff options
author | Gustaf Rydholm <gustaf.rydholm@gmail.com> | 2021-03-20 18:09:06 +0100 |
---|---|---|
committer | Gustaf Rydholm <gustaf.rydholm@gmail.com> | 2021-03-20 18:09:06 +0100 |
commit | 7e8e54e84c63171e748bbf09516fd517e6821ace (patch) | |
tree | 996093f75a5d488dddf7ea1f159ed343a561ef89 /src/text_recognizer/networks/cnn_transformer.py | |
parent | b0719d84138b6bbe5f04a4982dfca673aea1a368 (diff) |
Inital commit for refactoring to lightning
Diffstat (limited to 'src/text_recognizer/networks/cnn_transformer.py')
-rw-r--r-- | src/text_recognizer/networks/cnn_transformer.py | 158 |
1 files changed, 0 insertions, 158 deletions
diff --git a/src/text_recognizer/networks/cnn_transformer.py b/src/text_recognizer/networks/cnn_transformer.py deleted file mode 100644 index a2d7926..0000000 --- a/src/text_recognizer/networks/cnn_transformer.py +++ /dev/null @@ -1,158 +0,0 @@ -"""A CNN-Transformer for image to text recognition.""" -from typing import Dict, Optional, Tuple - -from einops import rearrange, repeat -import torch -from torch import nn -from torch import Tensor - -from text_recognizer.networks.transformer import PositionalEncoding, Transformer -from text_recognizer.networks.util import activation_function -from text_recognizer.networks.util import configure_backbone - - -class CNNTransformer(nn.Module): - """CNN+Transfomer for image to sequence prediction.""" - - def __init__( - self, - num_encoder_layers: int, - num_decoder_layers: int, - hidden_dim: int, - vocab_size: int, - num_heads: int, - adaptive_pool_dim: Tuple, - expansion_dim: int, - dropout_rate: float, - trg_pad_index: int, - max_len: int, - backbone: str, - backbone_args: Optional[Dict] = None, - activation: str = "gelu", - pool_kernel: Optional[Tuple[int, int]] = None, - ) -> None: - super().__init__() - self.trg_pad_index = trg_pad_index - self.vocab_size = vocab_size - self.backbone = configure_backbone(backbone, backbone_args) - - if pool_kernel is not None: - self.max_pool = nn.MaxPool2d(pool_kernel, stride=2) - else: - self.max_pool = None - - self.character_embedding = nn.Embedding(self.vocab_size, hidden_dim) - - self.src_position_embedding = nn.Parameter(torch.randn(1, max_len, hidden_dim)) - self.pos_dropout = nn.Dropout(p=dropout_rate) - self.trg_position_encoding = PositionalEncoding(hidden_dim, dropout_rate) - - nn.init.normal_(self.character_embedding.weight, std=0.02) - - self.adaptive_pool = ( - nn.AdaptiveAvgPool2d((adaptive_pool_dim)) if adaptive_pool_dim else None - ) - - self.transformer = Transformer( - num_encoder_layers, - num_decoder_layers, - hidden_dim, - num_heads, - expansion_dim, - dropout_rate, - activation, - ) - - self.head = nn.Sequential( - # nn.Linear(hidden_dim, hidden_dim * 2), - # activation_function(activation), - nn.Linear(hidden_dim, vocab_size), - ) - - def _create_trg_mask(self, trg: Tensor) -> Tensor: - # Move this outside the transformer. - trg_pad_mask = (trg != self.trg_pad_index)[:, None, None] - trg_len = trg.shape[1] - trg_sub_mask = torch.tril( - torch.ones((trg_len, trg_len), device=trg.device) - ).bool() - trg_mask = trg_pad_mask & trg_sub_mask - return trg_mask - - def encoder(self, src: Tensor) -> Tensor: - """Forward pass with the encoder of the transformer.""" - return self.transformer.encoder(src) - - def decoder(self, trg: Tensor, memory: Tensor, trg_mask: Tensor) -> Tensor: - """Forward pass with the decoder of the transformer + classification head.""" - return self.head( - self.transformer.decoder(trg=trg, memory=memory, trg_mask=trg_mask) - ) - - def extract_image_features(self, src: Tensor) -> Tensor: - """Extracts image features with a backbone neural network. - - It seem like the winning idea was to swap channels and width dimension and collapse - the height dimension. The transformer is learning like a baby with this implementation!!! :D - Ohhhh, the joy I am experiencing right now!! Bring in the beers! :D :D :D - - Args: - src (Tensor): Input tensor. - - Returns: - Tensor: A input src to the transformer. - - """ - # If batch dimension is missing, it needs to be added. - if len(src.shape) < 4: - src = src[(None,) * (4 - len(src.shape))] - - src = self.backbone(src) - - if self.max_pool is not None: - src = self.max_pool(src) - - if self.adaptive_pool is not None and len(src.shape) == 4: - src = rearrange(src, "b c h w -> b w c h") - src = self.adaptive_pool(src) - src = src.squeeze(3) - elif len(src.shape) == 4: - src = rearrange(src, "b c h w -> b (h w) c") - - b, t, _ = src.shape - - src += self.src_position_embedding[:, :t] - src = self.pos_dropout(src) - - return src - - def target_embedding(self, trg: Tensor) -> Tuple[Tensor, Tensor]: - """Encodes target tensor with embedding and postion. - - Args: - trg (Tensor): Target tensor. - - Returns: - Tuple[Tensor, Tensor]: Encoded target tensor and target mask. - - """ - trg = self.character_embedding(trg.long()) - trg = self.trg_position_encoding(trg) - return trg - - def decode_image_features( - self, image_features: Tensor, trg: Optional[Tensor] = None - ) -> Tensor: - """Takes images features from the backbone and decodes them with the transformer.""" - trg_mask = self._create_trg_mask(trg) - trg = self.target_embedding(trg) - out = self.transformer(image_features, trg, trg_mask=trg_mask) - - logits = self.head(out) - return logits - - def forward(self, x: Tensor, trg: Optional[Tensor] = None) -> Tensor: - """Forward pass with CNN transfomer.""" - image_features = self.extract_image_features(x) - logits = self.decode_image_features(image_features, trg) - return logits |