Study on elderly speech recognition for achieving speech interfaces in ubiquitous computing environment

普适计算环境下老年人语音识别实现语音接口的研究

• 批准号: 17560345
• 负责人: NIYADA Katsuyuki
• 金额: $ 2.3万
• 依托单位: Kyushu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560345/
• 关键词: elderly speech; hoarse voice; briskness of voice; speech recognition; speech interface; 高齢者; ユビキタス

Speech recognition technology is attractive as one of friendly human-machine interfaces for elderly people. However, elderly speech causes a great decrease in the performance of speech recognition compared to non-elderly adult speech. This study aims at improving the recognition rate of elderly speech, and carries out acoustic analysis to examine the acoustic characteristic of elderly speech quantitatively.This study focused on "non-briskness" and "hoarseness" as the nature of elderly speech, and successfully found the relationship between subjective characteristics given by listening tests and objective features obtained by acoustic analysis.Concerning the non-brisk elderly voice, it is well known that subjective non-briskness is caused by the vague movements of the articulatory organs due to aging. In this study, we found that the degree of subjective non-briskness related to the temporal movement of spectral envelops between succeeding phonemes. Furthermore, time evolution of speech power has the relationship with the subjective non-briskness as well as the temporal movement of spectral envelopes.Concerning the hoarse elderly voice, we consider that noise occurred at the aged vocal cords impresses us the subjective hoarseness. We compared the averaged amplitude spectra between elderly hoarse voices and normal voices uttered by non-elderly adults for each of Japanese vowels, and found that elderly hoarse voice had power decrease and increase in the mid frequency range (1.5 kHz-2.5 kHz) and the high frequency range over 2.5 kHz, respectively. We explain this phenomenon briefly by using tilt of amplitude spectrum. Speech recognition was carried out with the preprocessor, which adjusts the spectral tilt of elderly voice to that of non-elderly adult, and we confirmed the preprocessor worked well on the vowel recognition task. Therefore, we conclude that the hoarseness is one of the reasons for the worse recognition rate of elderly speech.

语音识别技术作为一种对老年人友好的人机接口，具有很大的吸引力。然而，与非老年人的语音相比，老年人的语音导致语音识别性能的大幅下降。本研究以提高老年人语音识别率为目的，通过声学分析定量研究老年人语音的声学特征，针对老年人语音的“不轻快”和“嘶哑”这两个特征，成功地找到了听力测试的主观特征与声学分析的客观特征之间的关系。众所周知，主观的不轻快是由由于年龄增长而引起的发音器官的模糊运动引起的。在这项研究中，我们发现，主观非轻快的程度有关的时间移动的频谱之间的后续音素。此外，语音功率的时间演化与主观非轻快度以及频谱包络的时间移动有关，对于老年人的声音嘶哑，我们认为，老年人声带处的噪声使我们感觉到主观嘶哑。我们比较了老年人嘶哑嗓音和非老年人正常嗓音的每个日语元音的平均幅度谱，发现老年人嘶哑嗓音的功率分别在中频范围（1.5 kHz-2.5 kHz）和2.5 kHz以上的高频范围内降低和增加。我们用振幅谱的倾斜对这一现象作了简要的解释。语音识别进行了预处理器，它调整了老年人的声音的频谱倾斜，非老年人的成年人，我们证实预处理器工作良好的元音识别任务。因此，我们认为声音嘶哑是导致老年人语音识别率下降的原因之一。