Yasushi Yamazaki

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We propose a text-independent speaker verification method based on a speech coding scheme. The proposed method utilizes CELP parameters which are used in speech coding schemes for mobile communication systems, and verifies a speaker only with the encoded speech information. The reliability of the proposed method under noisy conditions is mainly discussed(More)
We propose an HMM-based text-indicated writer verification method, which is based on a challenge and response type of authentication process. In this method, a different text including ordinary characters is used on every occasion of verification. This text can be selected automatically by the verification system so as to reflect a specific writer's(More)
The analysis of vulnerabilities and threats in biometrics-based personal authentication systems is indispensable for the development and promotion of wide spread utilization of biometric technologies in accordance with international standardization of information security technologies. In this paper, we discuss the vulnerabilities and threats in a writer(More)
W e propose an on-line writer verification method to improve the reliability of verifying a specific system user. In the proposed method, a different text including ordina y characters is used on eve y verification process. This text can be selected automatically by the verification system so as to reflect the specific writer's fentures. A specific writer(More)
The conventional mouth gender recognition is based on a static image and ignore the dynamic information. In this paper, we propose a lip movement gender recognition method to improve the accuracy by exploring the dynamic information while a user is speaking. In order to overcome the difficulty caused by the nonlinear distribution of the lip images, Gausian(More)
We developed a dental fiberscope with a navigation system. The aim of this study is to direct the position of the tip of the endoscope fiber in the root canal via our navigation system. The distinguishing characteristic of our system is that it could be particularly practical in narrow spaces, such as those involving endodontic treatment typical of root(More)
Recently, with the rapid spread of smart devices, such as smart-phones and tablet PCs, biometric authentication using handwritten signatures on such devices has been attracting much interest. However, little research has been reported on biometric-bit-string generation from handwritten signatures, which is indispensable for biometric-template protection on(More)