FILTER CHARACTERISTICS OF FINE-SURFACE-TEXTURE DISCRIMINATION IN HUMAN TACTILE PERCEPTION

Miyaoka等人提出了“幅度信息假说”，用于解释人类触觉感知中精细表面纹理辨别的机制。触觉信息处理系统具有低通滤波特性，仅通过滤波器的幅度信息用于辨别任务。本研究的目的是探讨低通滤波器的特性。1.建立了一个数学模型，以显示触觉系统具有低通滤波器时所观察到的情况。在衍射光栅粗糙度辨别任务中，数学模型预测了辨别任务的心理测量学功能呈现出特定的模式。2.在主动触摸实验中，以衍射光栅为刺激。波长范围为6.7 ~ 75.2 μm。受试者在刺激物上以20 mm/s的速度移动食指。他们判断粗糙的刺激与两个选择，强迫选择技术。从实验数据中计算出心理测量函数。心理测量函数的形状与模型预测的结果相似。低通滤波器的频率上限在400 ~ 600 Hz之间。3.在被动触摸实验中，使用波长为33.3 ~ 150.4 μm的衍射光栅作为刺激。使用实验仪器以60 mm/s的速度移动刺激。受试者触摸运动刺激，并判断刺激的粗糙度。实验结果与模型的预测相吻合，模型和实验结果均支持幅度信息假说。

Miyaoka et al. proposed "amplitude-information hypothesis" for the mechanisms of fine-surface-texture discrimination in human tactile perception. The tactile information-processing system has low-pass-filter characteristics and the amplitude information only passed through the filter was used for the discrimination tasks. The Purpose of this study was to investigate the low-pass filter characteristics.1.A mathematical model was produced to show what was observed if the tactile system had the low-pass filter. In roughness discrimination tasks of diffraction gratings, the mathematical model predicted that the psychometric functions of discrimination tasks showed specific patterns.2.In an active-touch experiment, diffraction gratings were used as stimuli. Their wavelengths were from 6.7 to 75.2 μm. Subjects moved their index fingers with velocity of 20 mm/s on the stimuli. They judged roughness of the stimuli with two-alternative, forced-choice technique. Psychometric functions were calculated from the data of the experiment. Shapes of the psychometric functions were similar to the results predicted by the model. The upper-limit frequency of the low-pass filter was between 400 and 600 Hz.3.In a passive-touch experiment, diffraction gratings, from 33.3 to 150.4 μm in wavelength, were used as stimuli. The stimuli were moved using an experimental instrument with a velocity of 60 mm/s. Subjects touched the moving stimuli and judged the roughness of stimuli. The experimental results coincided with the predictions of the model.The model and the results of the experiments supported the amplitude-information hypothesis.