Information Extraction with DONUT
We live in world of big data. The plethora of data gets generated from person’s day-to-day activity i.e. banking, social media, insurance, etc. Most of the time this data gets stored in an unstructured way. To perform data analysis on such data is quite a challenging task. We are going to discuss a state-of-the-art technique to solve such challenging problems.
Extracting data from unstructured documents is always a challenge. Previously we used to have rule-based approaches to tackle such problems. However, due to the nature of the rule-based mechanism, external knowledge source, and manpower is required. To solve such issues, NLP is always a go-to solution for everyone.
Deep learning has revolutionized the NLP field and to add to it hugging face has always delivered state-of-the-art solutions for multiple problems in NLP. We’re going to discuss one of the SOTA called DONUT.
The DONUT model is proposed in the OCR-free Document Understanding Transformer(DONUT) category by Geewook Kim, Teakgyu Hong, Moonbin Yim, Jeongyeon Nam, Jinyoung Park, Jinyeong Yim, Wonseok Hwang, Sangdoo Yun, Dongyoon Han, Seunghyun Park. Donut includes an image Transformer encoder and an autoregressive text Transformer decoder to understand the document. It is widely used for Image classification, form understanding, and visual question answering.
DONUT proposes to solve the following problems.
- CORD (form understanding)
- DocVQA (visual question answering on documents)
- RVL-DIP (document image classification)
In this blog, we will talk about visual question answering on documents.
DONUT consists of a Transformer based visual encoder and textual decoder modules. In which visual encode extracts relevant features from document and textual decoder convert the derived features into a sequence of sub word to generate a desired output. DONUT doesn’t relay on any of the OCR-module.
Let us consider one example to understand it better.
This is the sample payslip document(Source Internet). The task is to extract the information like
- “Employee Name”
- “Total working Day”
- “Final Net pay”
- “Total Deduction”
A possible solution would be to create a template and store the bounding box information for each entity. Such approaches work well when no different variations exist. Another possible approach would be using Layoutlm with finetuning on specific task.
DONUT comes to rescue here with an already pre-trained model, which requires very little or no finetuning.
Let us take a walkthrough of the code. We have used the “Google colab” for ease of exploration.
- To speed up the processing GPU require. Please select processing unit as GPU.
2. Install the packages.
3 . Load the image of payslip. Any Specific image can also be used.
4. Load the Process and model
5. Encode image using the Processor
Prepare the image for the model using DonutProcessor.
6. Prediction on the questions
7. Output
Observations
If we analyze the results, it looks pretty cool. Please keep in mind following points.
- Document image quality should be high otherwise OCR (Optical Character Recognition) might be wrong for lower-resolution images.
- Please be specific while drafting the question. Your question should contain a keywords/phrase around your answer. It will yield good results.
- It can also extract the value from paragraphs as well. If required field/data exist in paragraph, then asking specific question around context yield the results.
Consider the sentence, “. The next meeting of the ACP is scheduled during November 28–30, 2022.”
To extract the answer, “When is ACP meeting scheduled?” question can be asked.
Conclusion
I specifically tested with different images are results are quite breathtaking. Please make sure to use high-resolution images. It will produce much better results.
Please check out the full code here. In subsequent blogs I will share the detail about finetuning on custom set of data.
Follow me on Linkedin.
Special thanks to Anupam Madhwal for guiding the exploration and Shaksham Kapoor for review and help.
