CAPTCHA introduction (cont. 3)

聲音式Captcha(Sound-based Captcha)：

由電腦發出聲音，要求使用者進行聲音的辨識。通常是播放英文字母，以及英文的阿拉伯數字，這對某些在色彩或形狀上有知覺障礙的人無疑是項福音，但是這類的Captcha卻仍舊無法避免語言上的隔閡，當問題不是以熟悉的語言描述時，使用者有可能無法順利通過此類Captcha的測試。雖然聲音的Captcha無法以圖片方式呈現在論文中，但圖1.4中箭頭所指的符號，便是Google所使用的聲音式Captcha按鈕。

Sound-based CAPTCHA:

This CAPTCHA will give a sound sequence to the user and ask them to recognize what numbers and words are there. In general, this sequence uses numbers only. No doubt, this kind of CAPTCHA will help the people with visual difficulty to solve the problem, but it can not across the language gap, neither. When the sequence is generated by a unknown language, the user may not be able to pass the test. We can hardly to put a voice sequence in the paper, but Fig. 1.4 shows a mark which is the bottom of the Google’s sound-based CAPTCHA.