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首先，本研究先說明各式觸覺圖形的製作方式，並解說SENSEG公司發展的靜電式觸覺平台(Feel-screen)，研究者取此平台進行觸覺符號的研究。前期研究先使用此平台所提供的三種質感(粗糙、紙材、平滑)測試畫面，透過實驗者的介紹並且讓使用者進行約30分鐘的試用，再以SUS問卷進行訪談，了解使用者對於靜電式觸覺方式的使用者感受。在11位無視力狀態人士(包含：2位盲眼者、6位矇眼的弱視者，平均年齡 37.6 歲，加上3位矇眼的明眼者，平均年齡 42.0 歲)的訪談意見中，全體受訪者都能夠感受到靜電式觸覺平台的觸感，其SUS的平均評量分數為38.18分，試用者希望能夠加強觸覺震動的感受度，也由於是新的觸覺體驗，使用者覺得需要時間去學習介面，研究者也發現，手指滑動的速度太快，會造成受測者感受不到觸覺震動的現象。
其後，研究者設計三階段的實驗，了解觸覺符號設計原則在靜電式觸覺平台上的可能修正方向。第一階段實驗：「靜電式觸覺線條辨識實驗」，測試靜電式觸覺平台的最小線條辨識間距，接受試用訪談的同樣11名無視力狀態人士，在靜電式觸覺平板上重複的辨識不同平行線間距(2mm~7mm)的觸覺線條數量，實驗者紀錄受測者回報的線條數量，並轉換為「辨識正確率」，在SPSS 19.0版的重複量數變異數分析下，出現顯著性(F(5,6)=18.474, p=0.001)，再由LSD事後檢定法發現，高辨識正確率群有四種(6mm、7mm、5mm、4mm)，由此判定4mm時為靜電式平行線最小間距，其辨識正確率為49%，此平行間距大於實體式的兩線間距(1.9mm)。
第三階段實驗，「靜電式觸覺路徑模擬實驗」，另外10位視覺受損人士(包含：2位後天盲眼者、8位矇眼的弱視者，平齡 56.0 歲)，在靜電式觸覺平台上，設計兩種搭配高低頻聲音的靜電式路徑線條，路徑寬度10mm，長度90mm，其中間各穿插4條叉路(寬度為3mm)，受測者戴著耳機，可以聽到觸摸線條時所發出的聲音，受測者被隨機分派在路徑線上進行模擬行走，兩種路徑線都完成後，實驗者詢問其對於兩種路徑形式的相對喜好性，實驗者記錄兩種路徑形式的喜好次數，以卡方檢定雖然並未出現顯著性(p=0.58)，但是80%的受測者相對喜好(低音路徑、高音叉路)的路徑設計。
This research aims on testing the usability of a new developing electrostatic tactile device. Since the fast growing of electron technology, traditional tactile map can be transformed into a type of electro-tactile map in portable devices. This research has two purposes: (1) to review and check whether the design guidelines of traditional tactile map are suitable for the new electrostatic device (2) to see the performance of the new device and to offer new possibility of design principles for the device.
In the beginning, a survey of the new kind of electro-tactile technology is explained. One of the systems Feel-screen, developed by the SENSEG, plays as the platform to study the guidelines of electrostatic tactile symbols. In a pilot research on the new tactile device, three pictures of tactile textures, (rough surface, paper surface, smooth surface), are showed to visually impaired users and they are allowed to test the device within 30 minutes under the introduction by the experimenter. Then a SUS questionnaires are approached and an interview by the experimenter in order to know the opinions from those users. The users include 11 persons (2 blinds and 6 amblyopia that the mean age is 37.6 years, and 3 blindfolded sights with mean age of 42.0 years). Though they all described that they feel the vibrations of the graphics from the device, the mean score of SUS is 38.18. From the observation of their operation on the device, the sensation of the electrostatic vibration will be ignored by the fast finger movement on the screen.
Later on, a three-stage of experiment is employed to realize the suitability of the guidelines of designing tactile symbols that were introduced from the physical tactile material. Firstly, electrostatic tactile parallel line experiment, those 11 users are asked to use their finger to count a serial of parallel lines that were designed at the screen of the Feelscreen. There were 6 sets of parallel lines; distances between the lines varied from 2mm to 7mm, adding 1mm a set at a time. The users were asked to count the numbers of each set of lines. The experimenter recorded the number responded from the user, and transformed it into correct rate . The mean correct rate was analyzed with repeat measurement of ANOVA in SPSS V12.0. There is a significant difference found among those mean correct rates, the Post Hoc of LSD shows that the higher score group including 6mm, 7mm, 5mm, and 4mm. The condition with gap of 4mm, correct rate of count of 49%, can be the candidate of the minimum gap between lines on the electrostatic tactile device. This gap is larger than the physical tactile material (1.9mm).
Secondly, electrostatic tactile symbol experiment, there were 6 tactile symbols (9 mm in size) showed on the screen of the device including triangle, square, and circle, which have a different texture type (line boundary, solid shape). Those 11 users who joined the parallel test were also asked to verify those 6 symbols in a time limit of 30 seconds per symbol. The experimenter recorded the response of symbol name from the participant, and the times of all symbols were listed in a confusion matrix with recognition rate. The result finds that boundary circle has a correct recognition rate of 45.5%, as well as the solid triangle has a correct recognition rate of 36.4%, that are relatively higher correct recognition among each type of symbols.
The final experiment, electrostatic tactile trail test, 10 other users, 2 late blinds and 8 amblyopia that with mean age of 56.0 years, were asked to test two trails on the screen. Each trail had a 90 mm length and 10 mm width. There were 4 cross road with 3 mm width in each trail represented the intersection trails. The different design between the two trails was the electrostatic sound paired to the tail, which was high frequency sound or low frequency sound. The participant put an earphone on and was hint to notice change of the sound when they following the trail to the end. After finishing the two simulations on the trails, participant was to choose the better design to the experimenter. Though the data shows only near the significant level (p=0.58), almost all of the users (80%) like the design that using lower frequency of sound on the main trail path and higher frequency of sound on the cross road.
On the end, another SUS test was launched to those 10 users to see the effect of audio on the electrostatic tactile device. It shows a promising result on the mean SUS score of 68.50 that is higher than the score by only tactile information, 38.18. It is a hint that tactile and audio should be combined and well paired for those users.
The results of this study hint that electrostatic tactile lines should have at least 4 mm of gap distance; the tactile symbols should also have prominent characteristic shape; and the main tail is preferred to paired with lower frequency of sound while the cross trail or other symbols should be paired with higher frequency of sound. In this way, the electrostatic device might be very helpful for the visually impaired person.
Hopefully, this study will give a reference on the design of electrostatic tactile symbols and to help the development of electrostatic tactile map. And the training of using the new device might be mentioned in the education as part of basic orientation and mobility course.