The Postal Code Recognition for Billing Envelopes

In this study, we proposed a versatile and robust postal code recognition system. The system can be applied to billing envelop sorting machines to help the postmen enhance the efficiency of mail sorting. The system can be roughly divided into six functions: envelope front/back recognition, envelope tilt degree estimation and correction, recognition of the postal information transparent window, characters region extraction, digit recognition, and postal code extraction. In the fifth function, ResNet-34 was trained with a self-produced dataset and is used to recognize the postal code digits. Based on the practical experimental result, the system has a certain level of precision and robustness.