Development of an acoustic monitoring support system to improve engineer' audibility over abnormal sounds in a ship engine room

船舶设备的声检是船舶维修工程师的一项重要工作。这种检查允许工人在早期阶段检测设备中的异常，或者在没有安装传感器的情况下注意到异常。视觉、听觉和嗅觉一起使用，可以阐明各种情况并检测异常。然而，高噪声水平的船舶机舱，防止工人发现异常的声音，因为掩蔽效应：接收一个不确定的微弱的声音是由噪音，来自主机和发电机在机舱。在大学生和工作人员的帮助下进行的一项评估听力的实验表明，纯音的可听度受到其频率和声压级的强烈影响。其次，在主机运行噪声作为掩蔽下研究了可听度。结果表明，听觉只受到暂时的掩蔽声与高度水平浪涌。通过这些实验，我们收集了关于面具和可听度的基础数据。使用这些数据，研究了减少掩蔽效应的方法。此外，我们还开发了一种听觉监测支持系统，可以提高难以区分的异常声音的可听度。在日本海洋工程学会会议上介绍了这些结果的报告，并在其附属刊物《海洋工程》第41卷第5期上发表。

Auditory inspection of marine equipment is an important task of an engineer for ship maintenance. Such inspection allows a worker to detect abnormalities in equipment at an early stage, or notice an anomaly where no sensor has been installed. Used together, visual, auditory, and olfactory senses can elucidate a broad range of situations and detect abnormalities. However, high noise levels in a ship engine room prevent workers from detecting abnormal sounds because of a masking effect: the reception of an indeterminate faint sound is blocked by noises that originate from the main engine and generator in the engine room.Our study investigated the relationship between masking noises and audibility. An experiment to assess hearing capabilities with the help of university students and staff has revealed that audibility for a pure tone is strongly affected by its frequency and sound pressure level. Next, audibility was investigated under the running noise of the main engine as a mask. Results indicated that audibility is affected only momentarily by a masking sound with a height level surge. We have collected fundamental data about masks and audibility through these experiments. Using those data, an approach to reduce masking effects was investigated. Furthermore, we have developed an auditory sense monitoring support system that improves audibility of abnormal sounds that are hard to distinguish. A report of those results was presented at the conference of the Japan Institution of Marine Engineering, and was published in Vol. 41, No. 5 of Marine Engineering, its affiliated journal.