利用人臉影像的三維資訊作身分驗證

Abstract

身分驗證是一個安全系統的基本元件。相較於傳統使用身分證明文件來作為驗證的依據，使用人臉來作身分驗證是一個良好且方便的方式。以往人臉辨識的方法是拿人臉影像中二維的資訊來作分析，它們忽略了人臉三維的資訊。本論文由三維的觀點來探討利用人臉作身分驗證的問題。在本論文中，人臉的三維資訊是由一種名為相關仿射結構的投影不變性來表現，同一個人臉的影像它的相關仿射結構是不變的。根據這個特性，我們可以建立一個根據人臉影像作驗證的身分驗證系統。

Identity verification is an essential component of a security system. The traditional way to verify a person is asking him to show some kind of document, e.g., an ID card. Compared to the traditional way, using human face to verify a person is a more convenient approach. We all know that a human face is a 3-D entity. However, existing face recognition methods analyze human face images in two dimensions, they discard 3-D information of the face images.The approach proposed in this thesis uses 3-D information of a face to do the verification. The 3-D information is represented by a projective invariant called relative affine structure. If the images are taken from the same person, the relative affine structures between these images remain unchanged. Based on such a property, an identity verification system using human face images can be built.