1. Auditory, Tactual, and Olfactory Displays
Chapter 6

2. Auditory, Tactual, and Olfactory Displays
Hearing 
Auditory Display 
Cutaneous Senses
Tactual Display 
Olfactory Sense 
Olfactory Display 

3. Hearing Nature and Measurement of Sound  Anatomy of the Ear 
Conversion of Sound Waves to Sensations 
Masking 

4. Hearing —Nature and Measurement of Sound
Frequency of Sound Waves
Sinusoidal (or sine) wave Fig 6-1
Pitch
Intensity of Sound
Complex Sound

5. Hearing —Nature and Measurement of Sound
Intensity of Sound
定義: power per unit area
單位: decibel (dB)
SPL(dB) = 10 log (P12/P02)= 20 log (P1/P0)
P0= 20μN/m2 (reference)
Sound-level-meter (combine 各種頻率)
Weighting networks: A, B, C (ANSI) Fig 6-2
(例) Sound level (A)=45dB, SLA=45dB, 45dB(A)

6. Hearing —Nature and Measurement of Sound
Complex Sound
Individual sine waves: combine Fig 6-3
Sound Spectrum: Spectral analysis
Sound → frequency bands, intensity
Frequency-band analyzer: Fig 6-4
bandwidth小 → more detail, lower sound level
ANSI: 10 bands
center freq.: 31.5, 63, 125,……
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7. Hearing —Anatomy of the Ear
Fig 6-5
Middle Ear: Acoustic (or aural) reflex
－End

8. Hearing —Conversion of Sound Waves to Sensations
Sensitive: 1000 – 5000 Hz.
－End

9. Hearing —Masking Operational definition: Selecting auditory signal:
Masking sound → threshold elevation
Selecting auditory signal:
需考慮環境噪音之 masking effect
Masking effect of pure tone Fig 6-6
Greatest effect: near the freq. (of masking tone) &
its harmonic overtones
Higher intensity: spread to higher freq.
Critical band: 可產生masking effect之頻率範圍
Higher freq. → larger critical band
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10. Auditory Display Auditory display preferable: p.169 
Detection of Signals 
Relative Discrimination 
Absolute Identification 
Localization 
Principles 
Specific Purpose 

11. Auditory Display — preferable
When the origin of the signal is itself a sound
When the message is simple and short
When the message will not be referred to later
When the message deals with events in time
When warnings are sent or when the message calls for immediate action
When continuously changing information of some type is presented

12. Auditory Display — preferable
When speech channels are fully employed
When the receiver moves from one place to another
When a verbal response is required (compatible)
When the visual system is overburdened
When illumination limits use of vision
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13. Auditory Display —Detection of Signals
SDT (a function of masking)
Quiet surroundings
40 – 50 dB above threshold
Duration: 至少 500 ms
Noisy
Min.: 15 dB above masked threshold
Max.: 25 dB above masked threshold
Midway: masked threshold — 110 dB
S/N ratio in the most sensitive 1/3 octave band

14. Auditory Display —Detection of Signals
Use of filters
Predominant freq. of noise ≠ signal
Method: filter out some of the noise
raise intensity of the remaining sound
→ increase S/N ratio
Increasing detectability (p.171)
Freq. 不同
Sound location 不同: phase-shift, both ear vs. one ear
在敏感頻帶(1000 – 4000 Hz)取4個以上主要頻率組成complex sound, 較不易masked
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15. Auditory Display —Relative Discrimination
Measure: JND
Discrimination of Intensity differences Fig 6-7
Above 60 db (smaller JND)
Freq.: intermediate (1000, 4000)
Discrimination of Frequency differences Fig 6-8
At least 30 dB
Freq. 太高→ JND 上升 (discrimination↓)
　Freq. 低→ 易與 noise相混
500 – 1000 Hz 適中
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16. Auditory Display —Absolute Identification
Multidimensional coding 為 佳
More dimensions
Fewer steps
－End

17. Auditory Display —Sound Localization
Stereophony: phase, intensity difference
定位能力差：方向前後相反，距離高估
Detect motion of a sound
MAMA (Minimum Audible Movement Angle)
depend on
Speed of movement
Initial position: 正前方(0º): 5º, 側邊(90º)：33º
較視覺差
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18. Auditory Display — Principles 1/3
P Fig 6-9
General Principles
Compatibility (e.g. high freq: up)
Approximation: two-stage signals
Attention-demanding signal
Designation signal
Dissociability
Discernible from any ongoing audio input
Parsimony
Invariance

19. Auditory Display — Principles 2/3
P Fig 6-9
Principles of Presentation
Avoid extremes of auditory dimensions
(e.g.) startle response
Establish intensity relative to ambient noise level
Not masked
Use interrupted or variable signals
Adaptation
Do not overload the auditory channel

20. Auditory Display — Principles 3/3
P Fig 6-9
Principles of Installation of Auditory Displays
Test signals to be used
Representative sample of potential user population
Avoid conflict with previously used signals
Facilitate changeover from previous display
－End

21. Auditory Display —Specific Purpose 1/3
Warning & Alarm Signals
聽覺特別適合
那一種聲音較適合 Fig
Intensity: Fig 6-11
SRT: 強, CRT: 中等
Recommendations P.180

22. Auditory Display —Specific Purpose 2/3
Warning & Alarm Signals
Recommendations P.180
200 – 5000 Hz
Travel long distance: below 1000 Hz
Bend around obstacles: below 500 Hz
Modulated signal: different enough
Frequency different from bk.
If different warning signals used: discriminable, moderate-intensity
Separate communication system

23. Auditory Display —Specific Purpose 3/3
Aids for the Blind (clear-path indicators)
Pathsounder
Single-object sensor
Sonic pathfinder
須 walk more slowly 問題
－End

24. Tactile Display 類型: Mechanical vs. Electrical 
Substitutes for Hearing 
Substitutes for Seeing 
Discussion 

25. Tactile Display —Mechanical vs. Electrical 1/2
Coding
Coding
Mechanical
Electrical
Location 
Frequency
Intensity
Duration
Phase ？

26. Tactile Display —Mechanical vs. Electrical 2/2
Electrical ＞ Mechanical
Less bulk
Lower power requirement
Independent of skin temperature
Electrical ＜ Mechanical
Elicit pain
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27. Tactile Display —Substitutes for Hearing
Reception of Coded Messages
5(chest location) × 3(intensity) × 3(duration)
=45 pattern (26 letters, 10 numbers, 4 words)
38 word/min ＞ Morse code (24 word/min)
Perception of Speech (×)
Localization of Sound: intensity difference
Ear (L&R): microphone
→Index fingers: vibrators
－End

28. Tactile Display —Substitutes for Seeing 1/3
Identification of Control
Coding: Shape, texture, size
Fig 6-14
Reading Printed Material
Braille printing (6個位置: 橫2縱3)
Optacon: Fig 6-15
optical-to-tactile converter

29. Tactile Display —Substitutes for Seeing 2/3
Navigation Aids
Environmental features
Point features
Linear features Fig 6-16
Areal features
Guide to use map
Tactile Graphs Fig 6-17
Incised-grid (bk) & raised lines: better
Raised-grid (bk): OK

30. Tactile Display —Substitutes for Seeing 3/3
Tracking-Task displays Fig 6-18
Single-task:
＋quickening ≒ visual display
quickening: predictor display
future consequences of a control
Dual-task:
visual-tactile (primary-secondary)
﹥visual-visual
－End

31. Tactile Display —Discussion
可用於 visual, auditory
Overburdened 時
Blind
－End

32. Olfactory Sense 1/2 揮發性分子之部份 Mechanism Receptors:
鼻腔 olfactory cell 之 olfactory hairs
Stimulus:
揮發性分子之部份

33. Olfactory Sense 2/2 特性 High false-alarm rate Absolute identification:
15-32 種 odor (complex stimulus)
3-4 種強度
Identification 差:可能因字彙少
Effective: detecting the presence of an odor
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34. Olfactory Display 缺點: 優點: 傳播易 用途: warning 適用: closed space, vast areas
Reliability 差
(例) stuff nose; Adaptation 快
Control 難
優點: 傳播易
用途: warning
(例) 瓦斯(gas), 礦坑(mine)
防火系統: CO2＋冬青味
適用: closed space, vast areas
－End