基于耳周围EMG信号的舌-机接口编解码技术研究

Research on Coding and Decoding Technology of Tongue-computer Interface Based on EMG Signal Around the Ear

  • 摘要: 人-机交互(Human-Computer Interface, HCI)是将人的意图或运动转为机器指令的技术。其中,利用生物电信号来实现人与外部设备之间实时通信的HCI系统可反映人体内部状态和预期行动,已广泛应用于健康监测、医疗诊断、航空航天、假肢和辅助设备的开发等多个领域。研究表明,基于肌电(Electromyography, EMG)的HCI系统稳定性强、实用化程度高,具有广阔的应用场景。其中,舌头运动具有高度的灵活性和可控性,诱发信号强且易于检测,因此通过舌动来控制外部设备的舌-机接口(Tongue-Computer Interface, TCI)具有重要的研究价值。然而现有研究的舌动信号采集方式仍然无法同时满足自然场景下高用户舒适度、精识别准确率和多控制指令集等方面的需求。为此,本研究设计了7种不同的舌头运动方式,分别为舌头“从左到右”、“从右到左”、“向上”、“向下”、“吐舌”、“卷舌”和“说‘talk’”运动,并采用更为便捷、舒适的电极放置方法获取了22名受试者的耳周围舌动EMG信号。本研究通过时、频域特征和共空间模式(Common Spatial Pattern, CSP)算法提取了舌动信号的多维信息,使用支持向量机(Support Vector Machines, SVM)进行了7种舌动模式的有效识别,22名受试者的7类舌动模式平均分类正确率最高可达94.25% ± 5.23%。本研究验证了舌头运动的耳周围EMG信号的稳定性和可分性,为后续开发高性能TCI系统、拓展HCI的应用场景奠定了基础。

     

    Abstract: ‍ ‍Human-computer interface (HCI) is a technology that converts human intentions or movements into instructions that the machine can understand. Among them, the HCI system, which uses bio-electric signals to realize real-time communication between human and external devices, can reflect the current internal state and expected action of a human, and has been widely used in many fields such as health monitoring, medical diagnosis, aerospace, prosthetics and auxiliary equipment development as well as many other fields. Some studies have shown that HCI system based on electromyography (EMG) signals has strong stability and high practicability, so it has broad application scenarios. Among these control modes, tongue movement is highly flexible and controllable, and the evoked signal has strong characteristics and can be detected easily, so tongue-computer interface (TCI), which controls external devices through tongue movement, has extremely important research value. However, the existing research methods of tongue movement signal acquisition still cannot meet the requirements of high user comfort, precision correct classification accuracy and multiple control command set in natural scenes at the same time. To this end, seven different tongue movements were designed in this study, which were “left to right”, “right to left”, “up”, “down”, “stick”, “roll” and “speak ‘talk’”. The EMG signals of tongue movements in the non-hair area around the ear of 22 subjects were obtained by a more convenient and comfortable electrode placement method compared with previous research. In this research, the multi-dimensional information of tongue movement signals was extracted by time and frequency domain features and space domain features which was extracted by Common Spatial Pattern (CSP) algorithm, and seven tongue movement patterns were effectively classified by Support Vector Machines (SVM) algorithm. Finally, our research showed that the average classification accuracy of the seven types of tongue movement patterns of 22 subjects was up to 94.25%±5.23%. At the end of this research, we verifies the stability and separability of the EMG signals around the ear of tongue movements, which lays the foundation for the subsequent development of a high performance TCI system and the expansion of HCI application scenarios for the foreseeable future.

     

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