System for recognizing online handwriting

A system for recognizing an online handwriting of a user comprising:

• a handwriting instrument including a body extending longitudinally between a first end and a second end, the first end having a writing tip which is able to write on a support, a module comprising at least one motion sensor configured to acquire motion data on the online handwriting of the user when the user is writing a characters sequence with the handwriting instrument,
• a calculating unit comprising a memory and a processor, the calculating unit communicating with the at least one motion sensor and configured to analyze the motion data by a machine learning model trained in a multitask way such that it is capable of performing a stroke segmentation task and a character classification task at a same time, wherein:
• the machine learning model comprises a shared backbone neural network configured to perform hidden features extraction of the motion data to obtain intermediate features,
• the stroke segmentation task is performed on the intermediate features, and
• the character classification task is performed using a recursive neural network using the intermediate features, and
• the machine learning model being configured to deliver as an output the characters sequence which was written by the user with the handwriting instrument.