Offline Detection of Misspelled Handwritten Words by Convolving Recognition Model Features with Text Labels

Offline handwriting recognition (HWR) has improved significantly with the advent of deep learning architectures in recent years. Nevertheless, it remains a challenging problem and practical applications often rely on post-processing techniques for restricting the predicted words via lexicons or language models. Despite their enhanced performance, such systems are less usable in contexts where out-of-vocabulary words are anticipated, e.g. for detecting misspelled words in school assessments. To that end, we introduce the task of comparing a handwriting image to text. To solve the problem, we propose an unrestricted binary classifier, consisting of a HWR feature extractor and a multimodal classification head which convolves the feature extractor output with the vector representation of the input text. Our model's classification head is trained entirely on synthetic data created using a state-of-the-art generative adversarial network. We demonstrate that, while maintaining high recall, the classifier can be calibrated to achieve an average precision increase of 19.5% compared to addressing the task by directly using state-of-the-art HWR models. Such massive performance gains can lead to significant productivity increases in applications utilizing human-in-the-loop automation.