handwrittenEsposallesCTC

Handwritten recognition model for Esposalles datasets, based on BLSTM and CTC.

My software environment:

• Ubuntu 16.04 x64
• Python 3.5
• TensorFlow 1.1

Structure:

It is a handwritten recognition model based on BLSTM and CTC. At this moment, I just use the simplest way to implement it: only 1 convolutional layer for feature extraction and followed by 1 BLSTM layer, and CTC as the loss function.

Esposalles Datasets:

In Esposalles datasets (available at Esposalles Datasets), there are 2 types: textline-based and word-based.

Figure 1. Textline-based Esposalles datasets

Figure 2. Word-based Esposalles datasets

Note: In my repository there is a folder named "groundTruth", which is to make the datasets easier using. So when you download the Esposalles datasets, please copy the groundtruth txt files to the corresponding folders.

Usage:

• esposallesData.py is to preprocess the Esposalles datasets, you can change to textline-based datasets or word-based ones by changing the bool value "TEXTLINE".
• esposallesSequenceCTC.py is the main program which has a class of SeqLearn().

Result:

During the running of the program, "train_cer.log" and "test_cer.log" will generate. When it finished, the character error rate can be visualized by showplt.py. For textline-based datasets (with the batch size of 8), the test CER reaches 10% at around 400th epoch. For word-based datasets (with the batch size of 64), the test CER reaches 13.5% at around 400th epoch. Here is the demo result:

Figure 3. Character error rate for textline-based datasets

Figure 4. Character error rate for word-based datasets

To be improved:

• This model has only 2 layers: one is convolutional and the other is BLSTM, so if more layers added, the result will be much better.
• Dynamic learning rate