A research on speech CAPTCHA systems

I am working on my presentation at WIT/SP meeting as follows.

Title: The comparison between the deletion-based methods and the mixing-based methods for safe speech CAPTCHA systems

Authors: Takuya NISHIMOTO, Hitomi MATSUMURA and Takayuki WATANABE

Abstract: Speech-based CAPTCHA systems, which distinguish between software agents and human beings, are especially important for persons with visual disability.  The popular approach is based on mixing-based methods, which use the mixed sounds of target speech and noises.  We have proposed a deletion-based method which uses the phonemic restoration effects.  Our approach can control the difficulty of tasks simply by the masking ratio. Our design principle of CAPTCHA insists that such tasks should be chosen so that the larger difference in performance between the machines and human beings can be provided.  In this paper, we give some hypotheses on the differences between the deletion-based method and the mixing-based methods.  We also show a plan of experiments which compare the automatic speech recognition performance, speech intelligibility, and mental workload of these two approaches.

Thu, Oct 29 – Fri, Oct 30, 2009

ASPAM (Aomori City, Japan)