AIlib2/ocrUtils/crnn_model/vgg_model.py

import torch.nn as nn
from .modules import VGG_FeatureExtractor, BidirectionalLSTM

class Model(nn.Module):

    def __init__(self, input_channel, output_channel, hidden_size, num_class,input_height=64):
        super(Model, self).__init__()
        """ FeatureExtraction """
        self.FeatureExtraction = VGG_FeatureExtractor(input_channel, output_channel)
        self.FeatureExtraction_output = output_channel

        if input_height==64:
            self.AdaptiveAvgPool = nn.AvgPool2d(kernel_size=(1, 3), stride=(1,1))
        elif input_height==32:    
            self.AdaptiveAvgPool = nn.AvgPool2d(kernel_size=(1, 1), stride=(1,1))
        else:
            self.AdaptiveAvgPool = nn.AdaptiveAvgPool2d((None, 1))
     
        """ Sequence modeling"""
        self.SequenceModeling = nn.Sequential(
            BidirectionalLSTM(self.FeatureExtraction_output, hidden_size, hidden_size),
            BidirectionalLSTM(hidden_size, hidden_size, hidden_size))
        self.SequenceModeling_output = hidden_size

        """ Prediction """
        self.Prediction = nn.Linear(self.SequenceModeling_output, num_class)


    def forward(self, input, text):
        """ Feature extraction stage """
        #print('####vgg_model.py line27:',input.size(), 'input[0,0,0:2,0:2] :',input[0,0,0:2,0:2])
        visual_feature = self.FeatureExtraction(input)
        #print('###line26:',visual_feature.size() )
        visual_feature = self.AdaptiveAvgPool(visual_feature.permute(0, 3, 1, 2))
        #print('###line29:',visual_feature.size())
        visual_feature = visual_feature.squeeze(3)

        """ Sequence modeling stage """
        contextual_feature = self.SequenceModeling(visual_feature)

        """ Prediction stage """
        prediction = self.Prediction(contextual_feature.contiguous())
        #print('###line39  vgg_model:',prediction.size())
        return prediction