SYSTEM FOR TRAINING MACHINE LEARNING MODEL WHICH RECOGNIZES CHARACTERS OF TEXT IMAGES

A system trains a machine learning model which recognizes characters of text images. The system stores the machine learning model which recognizes characters of text images. The machine learning model includes a character segmentation network which is configured to extract visual features from text images, and to generate character bounding boxes from the text images, a domain adaptation network configured to classify the text images into domains based on the visual features, and a text recognition network configured to recognize characters in the text images based on the character bounding boxes and the visual features. The system is configured to (1) reverse gradients in the training of the domain adaptation network to minus gradients and back-propagate the minus gradients through the character segmentation network (2) back-propagate gradients in the training of the text recognition network through the character segmentation network.