Before revision: Information Extraction (IE) for  document images is often approached as a BIO tagging problem , where the model sequentially goes through and classifies each recognized input token into one of the information categories.
After revision: Information Extraction (IE) for document images is often approached as a BIO tagging problem , where the model sequentially goes through and classifies each recognized input token into one of the IOB (Inside, Outside, and Beginning) categories.