Yasushi Yamazaki

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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)
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 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)
The design and development of a new fine fiberscope (1.0 mm outer diameter) is described, that includes an irrigation system for endoscopic use. This effectively allows visualisation of fields involved in periodontal disease. This fiberscope has been used in our clinic for seven years to diagnose and treat periapical and periodontal lesions through fistulae(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)
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)