Piecewise Bézier Curve Interpolation Model for Offline Signature Visualization

Abstract

Handwritten is a great method of biometric authentication and can be categorized into online signature and offline signature. Offline signatures are important in lots of formal settings. However, signature forging is a worrying issue due to its role in safeguarding our identity. Signature forging can be tackled by implementing signature verification. Offline signature verification featuring comparing image of signatures to the image of a reference signature. Morover, the storing of images takes up a lot of space. Hence, this study proposes a different way to store the reference signature which is using piecewise Bézier curve interpolation to visualize the signature. Bézier curve is a great tool for constructing a curve because of its straightforward nature. Bézier curve is a curve that can be shaped using a control polygon. Still, it does not coincide with all the control points. For this reason, Bézier curve interpolation is used to visualize the signature where the resulting curve is a curve that passed through every chosen points. In this study, some points are chosen and a reference signature is generated by using the chosen points as the control polygon. The existence of cusp in signature suggested that piecewise  Bézier curve is suitable for easing out the curve regeneration. The reference signature is then compared to the original signature using Harris algorithm. The piecewise Bézier curve interpolation can produce a reference signature that matched the original signature. In the study, it was found out that higher order Bézier curve should be a last resort in generating a reference signature. Since, it is harder to obtain a desire shape using a higher order Bézier curve to interpolate a curve.