From beeaef529e7c893a3475fe27edc880e283373725 Mon Sep 17 00:00:00 2001
From: aktersnurra <gustaf.rydholm@gmail.com>
Date: Sun, 8 Nov 2020 12:41:04 +0100
Subject: Trying to get the CNNTransformer to work, but it is hard.

---
 src/text_recognizer/networks/crnn.py | 40 ++++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 13 deletions(-)

(limited to 'src/text_recognizer/networks/crnn.py')

diff --git a/src/text_recognizer/networks/crnn.py b/src/text_recognizer/networks/crnn.py
index 3e605e2..9747429 100644
--- a/src/text_recognizer/networks/crnn.py
+++ b/src/text_recognizer/networks/crnn.py
@@ -1,12 +1,9 @@
 """LSTM with CTC for handwritten text recognition within a line."""
-import importlib
-from pathlib import Path
-from typing import Callable, Dict, List, Optional, Tuple, Type, Union
+from typing import Dict, Tuple
 
 from einops import rearrange, reduce
-from einops.layers.torch import Rearrange, Reduce
+from einops.layers.torch import Rearrange
 from loguru import logger
-import torch
 from torch import nn
 from torch import Tensor
 
@@ -28,16 +25,21 @@ class ConvolutionalRecurrentNetwork(nn.Module):
         patch_size: Tuple[int, int] = (28, 28),
         stride: Tuple[int, int] = (1, 14),
         recurrent_cell: str = "lstm",
+        avg_pool: bool = False,
+        use_sliding_window: bool = True,
     ) -> None:
         super().__init__()
         self.backbone_args = backbone_args or {}
         self.patch_size = patch_size
         self.stride = stride
-        self.sliding_window = self._configure_sliding_window()
+        self.sliding_window = (
+            self._configure_sliding_window() if use_sliding_window else None
+        )
         self.input_size = input_size
         self.hidden_size = hidden_size
         self.backbone = configure_backbone(backbone, backbone_args)
         self.bidirectional = bidirectional
+        self.avg_pool = avg_pool
 
         if recurrent_cell.upper() in ["LSTM", "GRU"]:
             recurrent_cell = getattr(nn, recurrent_cell)
@@ -76,15 +78,27 @@ class ConvolutionalRecurrentNetwork(nn.Module):
         """Converts images to sequence of patches, feeds them to a CNN, then predictions are made with an LSTM."""
         if len(x.shape) < 4:
             x = x[(None,) * (4 - len(x.shape))]
-        x = self.sliding_window(x)
 
-        # Rearrange from a sequence of patches for feedforward network.
-        b, t = x.shape[:2]
-        x = rearrange(x, "b t c h w -> (b t) c h w", b=b, t=t)
-        x = self.backbone(x)
+        if self.sliding_window is not None:
+            # Create image patches with a sliding window kernel.
+            x = self.sliding_window(x)
+
+            # Rearrange from a sequence of patches for feedforward network.
+            b, t = x.shape[:2]
+            x = rearrange(x, "b t c h w -> (b t) c h w", b=b, t=t)
 
-        # Avgerage pooling.
-        x = reduce(x, "(b t) c h w -> t b c", "mean", b=b, t=t)
+            x = self.backbone(x)
+
+            # Avgerage pooling.
+            if self.avg_pool:
+                x = reduce(x, "(b t) c h w -> t b c", "mean", b=b, t=t)
+            else:
+                x = rearrange(x, "(b t) h -> t b h", b=b, t=t)
+        else:
+            # Encode the entire image with a CNN, and use the channels as temporal dimension.
+            b = x.shape[0]
+            x = self.backbone(x)
+            x = rearrange(x, "b c h w -> c b (h w)", b=b)
 
         # Sequence predictions.
         x, _ = self.rnn(x)
-- 
cgit v1.2.3-70-g09d2