An experiment is described that tested the possibility to classify wooden, plastic, and metallic objects based on reproduced auditory and vibrotactile stimuli. The results show that recognition rates are considerably above chance level with either unimodal auditory or vibrotactile feedback. Supported by those findings, the possibility to render virtual buttons for professional appliances with different tactile properties was tested. To this end, a touchscreen device was provided with various types of vibrotactile feedback in response to the sensed pressing force and location of a finger. Different virtual buttons designs were tested by user panels who performed a subjective evaluation on perceived tactile properties and materials. In a first implementation, virtual buttons were designed reproducing the vibration recordings of real materials used in the classification experiment: mainly due to hardware limitations of our prototype and the consequent impossibility to render complex vibratory signals, this approach did not prove successful. A second implementation was then optimized for the device capabilities, moreover introducing surface compliance effects and button release cues: the new design led to generally high quality ratings, clear discrimination of different buttons and unambiguous material classification. The lesson learned was that various material and physical properties of virtual buttons can be successfully rendered by characteristic frequency and decay cues if correctly reproduced by the device.

中文翻译：

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材料特性的触觉辨别：应用于专业设备的虚拟按钮

描述了一个实验，该实验测试了根据再现的听觉和触觉刺激对木制，塑料和金属物体进行分类的可能性。结果表明，无论是单峰听觉还是触觉反馈，识别率都大大高于偶然水平。在这些发现的支持下，测试了为具有不同触觉特性的专业设备渲染虚拟按钮的可能性。为此，响应于感测到的按压力和手指的位置，向触摸屏设备提供各种类型的触觉反馈。用户面板对不同的虚拟按钮设计进行了测试，用户面板对感知的触觉特性和材料进行了主观评估。在第一个实现中 设计了虚拟按钮，可再现分类实验中使用的真实材料的振动记录：主要是由于我们原型的硬件限制以及随之而来的不可能呈现复杂的振动信号，这种方法并未获得成功。然后针对设备功能优化了第二种实现方式，此外还引入了表面柔顺效果和按钮释放提示：新设计带来了总体上高品质的评级，对不同按钮的清晰区分以及明确的材料分类。吸取的教训是，如果设备正确再现了虚拟按钮的各种材料和物理属性，则可以通过特征频率和衰减提示成功地呈现它们。主要是由于我们的原型的硬件限制以及随之而来的不可能呈现复杂的振动信号，这种方法并未获得成功。然后针对设备功能优化了第二种实现方式，此外还引入了表面柔顺效果和按钮释放提示：新设计带来了总体上高品质的评级，对不同按钮的清晰区分以及明确的材料分类。吸取的教训是，如果设备正确再现了虚拟按钮的各种材料和物理属性，则可以通过特征频率和衰减提示成功地呈现它们。主要是由于我们原型的硬件局限性以及随之而来的不可能呈现复杂的振动信号，这种方法并未获得成功。然后针对设备功能优化了第二种实现方式，此外还引入了表面柔顺效果和按钮释放提示：新设计带来了总体上高品质的评级，对不同按钮的清晰区分以及明确的材料分类。吸取的教训是，如果设备正确再现了虚拟按钮的各种材料和物理属性，则可以通过特征频率和衰减提示成功地呈现它们。此外，还引入了表面柔顺效果和按钮释放提示：新设计带来了总体上高品质的评级，对不同按钮的清晰区分以及明确的材料分类。吸取的教训是，如果设备正确再现了虚拟按钮的各种材料和物理属性，则可以通过特征频率和衰减提示成功地呈现它们。此外，还引入了表面柔顺效果和按钮释放提示：新设计带来了总体上高品质的评级，对不同按钮的清晰区分以及明确的材料分类。吸取的教训是，如果设备正确再现了虚拟按钮的各种材料和物理属性，则可以通过特征频率和衰减提示成功地呈现它们。