PaddleOCR/ppocr/modeling/heads/table_att_head.py

239 lines
10 KiB
Python

# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import paddle
import paddle.nn as nn
import paddle.nn.functional as F
import numpy as np
class TableAttentionHead(nn.Layer):
def __init__(self, in_channels, hidden_size, loc_type, in_max_len=488, **kwargs):
super(TableAttentionHead, self).__init__()
self.input_size = in_channels[-1]
self.hidden_size = hidden_size
self.elem_num = 30
self.max_text_length = 100
self.max_elem_length = 500
self.max_cell_num = 500
self.structure_attention_cell = AttentionGRUCell(
self.input_size, hidden_size, self.elem_num, use_gru=False)
self.structure_generator = nn.Linear(hidden_size, self.elem_num)
self.loc_type = loc_type
self.in_max_len = in_max_len
if self.loc_type == 1:
self.loc_generator = nn.Linear(hidden_size, 4)
else:
if self.in_max_len == 640:
self.loc_fea_trans = nn.Linear(400, self.max_elem_length+1)
elif self.in_max_len == 800:
self.loc_fea_trans = nn.Linear(625, self.max_elem_length+1)
else:
self.loc_fea_trans = nn.Linear(256, self.max_elem_length+1)
self.loc_generator = nn.Linear(self.input_size + hidden_size, 4)
def _char_to_onehot(self, input_char, onehot_dim):
input_ont_hot = F.one_hot(input_char, onehot_dim)
return input_ont_hot
def forward(self, inputs, targets=None):
# if and else branch are both needed when you want to assign a variable
# if you modify the var in just one branch, then the modification will not work.
fea = inputs[-1]
if len(fea.shape) == 3:
pass
else:
last_shape = int(np.prod(fea.shape[2:])) # gry added
fea = paddle.reshape(fea, [fea.shape[0], fea.shape[1], last_shape])
fea = fea.transpose([0, 2, 1]) # (NTC)(batch, width, channels)
batch_size = fea.shape[0]
hidden = paddle.zeros((batch_size, self.hidden_size))
output_hiddens = []
if self.training and targets is not None:
structure = targets[0]
for i in range(self.max_elem_length+1):
elem_onehots = self._char_to_onehot(
structure[:, i], onehot_dim=self.elem_num)
(outputs, hidden), alpha = self.structure_attention_cell(
hidden, fea, elem_onehots)
output_hiddens.append(paddle.unsqueeze(outputs, axis=1))
output = paddle.concat(output_hiddens, axis=1)
structure_probs = self.structure_generator(output)
if self.loc_type == 1:
loc_preds = self.loc_generator(output)
loc_preds = F.sigmoid(loc_preds)
else:
loc_fea = fea.transpose([0, 2, 1])
loc_fea = self.loc_fea_trans(loc_fea)
loc_fea = loc_fea.transpose([0, 2, 1])
loc_concat = paddle.concat([output, loc_fea], axis=2)
loc_preds = self.loc_generator(loc_concat)
loc_preds = F.sigmoid(loc_preds)
else:
temp_elem = paddle.zeros(shape=[batch_size], dtype="int32")
structure_probs = None
loc_preds = None
elem_onehots = None
outputs = None
alpha = None
max_elem_length = paddle.to_tensor(self.max_elem_length)
i = 0
while i < max_elem_length+1:
elem_onehots = self._char_to_onehot(
temp_elem, onehot_dim=self.elem_num)
(outputs, hidden), alpha = self.structure_attention_cell(
hidden, fea, elem_onehots)
output_hiddens.append(paddle.unsqueeze(outputs, axis=1))
structure_probs_step = self.structure_generator(outputs)
temp_elem = structure_probs_step.argmax(axis=1, dtype="int32")
i += 1
output = paddle.concat(output_hiddens, axis=1)
structure_probs = self.structure_generator(output)
structure_probs = F.softmax(structure_probs)
if self.loc_type == 1:
loc_preds = self.loc_generator(output)
loc_preds = F.sigmoid(loc_preds)
else:
loc_fea = fea.transpose([0, 2, 1])
loc_fea = self.loc_fea_trans(loc_fea)
loc_fea = loc_fea.transpose([0, 2, 1])
loc_concat = paddle.concat([output, loc_fea], axis=2)
loc_preds = self.loc_generator(loc_concat)
loc_preds = F.sigmoid(loc_preds)
return {'structure_probs':structure_probs, 'loc_preds':loc_preds}
class AttentionGRUCell(nn.Layer):
def __init__(self, input_size, hidden_size, num_embeddings, use_gru=False):
super(AttentionGRUCell, self).__init__()
self.i2h = nn.Linear(input_size, hidden_size, bias_attr=False)
self.h2h = nn.Linear(hidden_size, hidden_size)
self.score = nn.Linear(hidden_size, 1, bias_attr=False)
self.rnn = nn.GRUCell(
input_size=input_size + num_embeddings, hidden_size=hidden_size)
self.hidden_size = hidden_size
def forward(self, prev_hidden, batch_H, char_onehots):
batch_H_proj = self.i2h(batch_H)
prev_hidden_proj = paddle.unsqueeze(self.h2h(prev_hidden), axis=1)
res = paddle.add(batch_H_proj, prev_hidden_proj)
res = paddle.tanh(res)
e = self.score(res)
alpha = F.softmax(e, axis=1)
alpha = paddle.transpose(alpha, [0, 2, 1])
context = paddle.squeeze(paddle.mm(alpha, batch_H), axis=1)
concat_context = paddle.concat([context, char_onehots], 1)
cur_hidden = self.rnn(concat_context, prev_hidden)
return cur_hidden, alpha
class AttentionLSTM(nn.Layer):
def __init__(self, in_channels, out_channels, hidden_size, **kwargs):
super(AttentionLSTM, self).__init__()
self.input_size = in_channels
self.hidden_size = hidden_size
self.num_classes = out_channels
self.attention_cell = AttentionLSTMCell(
in_channels, hidden_size, out_channels, use_gru=False)
self.generator = nn.Linear(hidden_size, out_channels)
def _char_to_onehot(self, input_char, onehot_dim):
input_ont_hot = F.one_hot(input_char, onehot_dim)
return input_ont_hot
def forward(self, inputs, targets=None, batch_max_length=25):
batch_size = inputs.shape[0]
num_steps = batch_max_length
hidden = (paddle.zeros((batch_size, self.hidden_size)), paddle.zeros(
(batch_size, self.hidden_size)))
output_hiddens = []
if targets is not None:
for i in range(num_steps):
# one-hot vectors for a i-th char
char_onehots = self._char_to_onehot(
targets[:, i], onehot_dim=self.num_classes)
hidden, alpha = self.attention_cell(hidden, inputs,
char_onehots)
hidden = (hidden[1][0], hidden[1][1])
output_hiddens.append(paddle.unsqueeze(hidden[0], axis=1))
output = paddle.concat(output_hiddens, axis=1)
probs = self.generator(output)
else:
targets = paddle.zeros(shape=[batch_size], dtype="int32")
probs = None
for i in range(num_steps):
char_onehots = self._char_to_onehot(
targets, onehot_dim=self.num_classes)
hidden, alpha = self.attention_cell(hidden, inputs,
char_onehots)
probs_step = self.generator(hidden[0])
hidden = (hidden[1][0], hidden[1][1])
if probs is None:
probs = paddle.unsqueeze(probs_step, axis=1)
else:
probs = paddle.concat(
[probs, paddle.unsqueeze(
probs_step, axis=1)], axis=1)
next_input = probs_step.argmax(axis=1)
targets = next_input
return probs
class AttentionLSTMCell(nn.Layer):
def __init__(self, input_size, hidden_size, num_embeddings, use_gru=False):
super(AttentionLSTMCell, self).__init__()
self.i2h = nn.Linear(input_size, hidden_size, bias_attr=False)
self.h2h = nn.Linear(hidden_size, hidden_size)
self.score = nn.Linear(hidden_size, 1, bias_attr=False)
if not use_gru:
self.rnn = nn.LSTMCell(
input_size=input_size + num_embeddings, hidden_size=hidden_size)
else:
self.rnn = nn.GRUCell(
input_size=input_size + num_embeddings, hidden_size=hidden_size)
self.hidden_size = hidden_size
def forward(self, prev_hidden, batch_H, char_onehots):
batch_H_proj = self.i2h(batch_H)
prev_hidden_proj = paddle.unsqueeze(self.h2h(prev_hidden[0]), axis=1)
res = paddle.add(batch_H_proj, prev_hidden_proj)
res = paddle.tanh(res)
e = self.score(res)
alpha = F.softmax(e, axis=1)
alpha = paddle.transpose(alpha, [0, 2, 1])
context = paddle.squeeze(paddle.mm(alpha, batch_H), axis=1)
concat_context = paddle.concat([context, char_onehots], 1)
cur_hidden = self.rnn(concat_context, prev_hidden)
return cur_hidden, alpha