From 7e8e54e84c63171e748bbf09516fd517e6821ace Mon Sep 17 00:00:00 2001 From: Gustaf Rydholm Date: Sat, 20 Mar 2021 18:09:06 +0100 Subject: Inital commit for refactoring to lightning --- text_recognizer/networks/stn.py | 44 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 text_recognizer/networks/stn.py (limited to 'text_recognizer/networks/stn.py') diff --git a/text_recognizer/networks/stn.py b/text_recognizer/networks/stn.py new file mode 100644 index 0000000..e9d216f --- /dev/null +++ b/text_recognizer/networks/stn.py @@ -0,0 +1,44 @@ +"""Spatial Transformer Network.""" + +from einops.layers.torch import Rearrange +import torch +from torch import nn +from torch import Tensor +import torch.nn.functional as F + + +class SpatialTransformerNetwork(nn.Module): + """A network with differentiable attention. + + Network that learns how to perform spatial transformations on the input image in order to enhance the + geometric invariance of the model. + + # TODO: add arguments to make it more general. + + """ + + def __init__(self) -> None: + super().__init__() + # Initialize the identity transformation and its weights and biases. + linear = nn.Linear(32, 3 * 2) + linear.weight.data.zero_() + linear.bias.data.copy_(torch.tensor([1, 0, 0, 0, 1, 0], dtype=torch.float)) + + self.theta = nn.Sequential( + nn.Conv2d(in_channels=1, out_channels=8, kernel_size=7), + nn.MaxPool2d(kernel_size=2, stride=2), + nn.ReLU(inplace=True), + nn.Conv2d(in_channels=8, out_channels=10, kernel_size=5), + nn.MaxPool2d(kernel_size=2, stride=2), + nn.ReLU(inplace=True), + Rearrange("b c h w -> b (c h w)", h=3, w=3), + nn.Linear(in_features=10 * 3 * 3, out_features=32), + nn.ReLU(inplace=True), + linear, + Rearrange("b (row col) -> b row col", row=2, col=3), + ) + + def forward(self, x: Tensor) -> Tensor: + """The spatial transformation.""" + grid = F.affine_grid(self.theta(x), x.shape) + return F.grid_sample(x, grid, align_corners=False) -- cgit v1.2.3-70-g09d2