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

船舶设备听觉检测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发现设备异常，或者注意到没有安装传感器的异常。视觉、听觉和嗅觉一起使用，可以阐明各种情况并检测异常情况。然而，由于掩蔽效应，船舶机舱内的高噪音水平使工作人员无法探测到异常声音：接收不确定的微弱声音被机舱内主机和发电机发出的噪音所阻挡。我们的研究探讨了掩蔽噪声与可听性之间的关系。在大学生和工作人员的帮助下，一项评估听力能力的实验表明，纯音的可听性受到其频率和声压级的强烈影响。其次，研究了在主机运行噪声作为掩模下的可听性。结果表明，可听性仅受到具有高电平浪涌的掩蔽声的短暂影响。我们通过这些实验收集了关于口罩和可听性的基本数据。利用这些数据，研究了一种降低掩蔽效应的方法。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性。这些结果的报告在日本海洋工程学会的会议上提出，并发表在其附属杂志《海洋工程》第41卷第5期。

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.