A Smartphone User Verification Method Based on Finger-Writing of a Simple Symbol

Abstract

Writer verification based on finger-writing of a simple symbol on a touch screen is proposed herein. The users write a simple and well-known symbol, for example, a circle, triangle, or square. In addition, the users write the symbol using their finger instead of a pen on a tablet. This allows more convenience with the use of the proposed method. However, it was observed that the original approach and obtained verification performance were not reliable. In this work, we create a new database using thirty participants. By examining individual features extracted from the database, the risk of misjudgment is found. In order to solve this problem, a coordinate transformation method is introduced. Moreover, normalization is examined for fusing individual features by comparing three normalization methods. The proposed method with appropriate coordinate transformation and normalization achieves an equal error rate of 10.6% even when all participants write only a simple circle.