auditory, tactual, and olfactory displays chapter 6

Auditory, Tactual, Auditory, Tactual, and Olfactory and Olfactory

DisplaysDisplaysChapter 6Chapter 6

Auditory, Tactual, and Auditory, Tactual, and Olfactory DisplaysOlfactory Displays

HearingHearing Auditory DisplayAuditory Display Cutaneous SensesCutaneous Senses Tactual DisplayTactual Display Olfactory SenseOlfactory Sense Olfactory DisplayOlfactory Display

HearingHearing

Nature and Measurement of Sound Nature and Measurement of Sound

Anatomy of the Ear Anatomy of the Ear

Conversion of Sound Waves to Sensations Conversion of Sound Waves to Sensations

Masking Masking

HearingHearing ——Nature and Nature and Measurement of SoundMeasurement of Sound

Frequency of Sound WavesFrequency of Sound Waves

Sinusoidal (or sine) wave Sinusoidal (or sine) wave Fig 6-1Fig 6-1

PitchPitch

Intensity of SoundIntensity of Sound

Complex SoundComplex Sound

Hearing Hearing ——Nature and Measurement Nature and Measurement of Soundof Sound

Intensity of SoundIntensity of Sound 定義定義 : power per unit area: power per unit area

單位單位 : decibel (dB): decibel (dB) SPL(dB) = 10 log (PSPL(dB) = 10 log (P11

22/P/P0022)= 20 log (P)= 20 log (P11/P/P00))

PP00= 20= 20μμN/mN/m2 2 (reference)(reference)

Sound-level-meter Sound-level-meter (combine (combine 各種頻率各種頻率 )) Weighting networks: A, B, C (ANSI) Weighting networks: A, B, C (ANSI) Fig 6-2Fig 6-2

(( 例例 ) Sound level (A)=45dB, SLA=45dB, 45dB(A)) Sound level (A)=45dB, SLA=45dB, 45dB(A)

Hearing Hearing ——Nature and Nature and Measurement of SoundMeasurement of Sound

Complex SoundComplex Sound Individual sine waves: combine Individual sine waves: combine Fig 6-3Fig 6-3

Sound Spectrum: Sound Spectrum: Spectral analysisSpectral analysis

Sound Sound →→ frequency bands, intensity frequency bands, intensity

Frequency-band analyzer: Frequency-band analyzer: Fig 6-4Fig 6-4

bandwidthbandwidth 小小 → → more detail, lower sound levelmore detail, lower sound level

ANSI: 10 bandsANSI: 10 bands

center freq.: 31.5, 63, 125,……center freq.: 31.5, 63, 125,……

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Hearing Hearing —Anatomy of the Ear—Anatomy of the Ear

Fig 6-5Fig 6-5

Middle Ear: Acoustic (or aural) Middle Ear: Acoustic (or aural) reflexreflex

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HearingHearing ——Conversion of Sound Conversion of Sound Waves to SensationsWaves to Sensations

Sensitive: 1000 – 5000 Hz.Sensitive: 1000 – 5000 Hz.

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Hearing Hearing ——MaskingMasking

Operational definition: Operational definition: Masking sound → threshold elevationMasking sound → threshold elevation

Selecting auditory signal: Selecting auditory signal: 需考慮環境噪音之 需考慮環境噪音之 mmasking effectasking effect

Masking effect of pure toneMasking effect of pure tone Fig 6-6Fig 6-6

Greatest effect: near the freq. (of masking tone) &Greatest effect: near the freq. (of masking tone) & its harmonic overtonesits harmonic overtones

Higher intensity: spread to higher freq.Higher intensity: spread to higher freq.

Critical band: Critical band: 可產生可產生 masking effectmasking effect 之頻率範圍之頻率範圍 Higher freq. Higher freq. → → larger critical bandlarger critical band － End

Auditory DisplayAuditory Display

Auditory display preferable: Auditory display preferable: p.169 p.169

Detection of Signals Detection of Signals

Relative Discrimination Relative Discrimination

Absolute Identification Absolute Identification

Localization Localization

Principles Principles

Specific Purpose Specific Purpose

Auditory DisplayAuditory Display — — preferablepreferable

When the origin of the signal is itself a soundWhen the origin of the signal is itself a sound

When the message is When the message is simplesimple and and shortshort

When the message will When the message will not not be be referredreferred to later to later

When the message deals with events in When the message deals with events in timetime

When When warningwarnings are sent or when the message s are sent or when the message calls for calls for immediateimmediate actionaction

When continuously When continuously changingchanging information of information of some type is presentedsome type is presented

Auditory DisplayAuditory Display — — preferablepreferable

When speech channels are fully employedWhen speech channels are fully employed

When the receiver When the receiver movemoves from one place s from one place to anotherto another

When a verbal response is required When a verbal response is required (compatible)(compatible)

When the visual system is overburdenedWhen the visual system is overburdened

When illumination limits use of visionWhen illumination limits use of vision

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Auditory DisplayAuditory Display —Detection of —Detection of SignalsSignals

SDT SDT (a function of masking)(a function of masking)

Quiet surroundingsQuiet surroundings 40 – 50 dB above threshold40 – 50 dB above threshold Duration: Duration: 至少 至少 500 ms500 ms

NoisyNoisy Min.: 15 dB above masked thresholdMin.: 15 dB above masked threshold Max.: 25 dB above masked thresholdMax.: 25 dB above masked threshold Midway: masked threshold Midway: masked threshold — — 110 dB110 dB S/N ratio in the most sensitive 1/3 octave bandS/N ratio in the most sensitive 1/3 octave band

Auditory DisplayAuditory Display —Detection of —Detection of SignalsSignals

Use of filtersUse of filters Predominant freq. of noise Predominant freq. of noise ≠ signal≠ signal

Method: filter out some of the noiseMethod: filter out some of the noise raise intensity of the remaining sound raise intensity of the remaining sound → → increase S/N ratioincrease S/N ratio

Increasing detectability Increasing detectability (p.171)(p.171)

Freq. Freq. 不同不同 Sound location Sound location 不同不同 : phase-shift, both ear vs. one ear: phase-shift, both ear vs. one ear

在敏感頻帶在敏感頻帶 (1000 – 4000 Hz)(1000 – 4000 Hz) 取取 44 個以上主要頻率組個以上主要頻率組成成 complex sound, complex sound, 較不易較不易 maskedmasked

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Auditory DisplayAuditory Display —Relative —Relative DiscriminationDiscrimination

Measure: JNDMeasure: JND Discrimination of Intensity differences Discrimination of Intensity differences Fig 6-7Fig 6-7

Above 60 db (smaller JND)Above 60 db (smaller JND)

Freq.: intermediate (1000, 4000) Freq.: intermediate (1000, 4000)

Discrimination of Frequency differences Discrimination of Frequency differences Fig 6-8Fig 6-8

At least 30 dBAt least 30 dB

Freq. Freq. 太高太高→ → JND JND 上升 上升 (discrimination↓)(discrimination↓) Freq. Freq. → 低 易與→ 低 易與 noisenoise 相混相混 500 – 1000 Hz 500 – 1000 Hz 適中適中 － End

Auditory DisplayAuditory Display —Absolute —Absolute IdentificationIdentification

Multidimensional coding Multidimensional coding 為佳為佳

More dimensionsMore dimensions Fewer stepsFewer steps

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Auditory DisplayAuditory Display —Sound —Sound LocalizationLocalization

Stereophony: Stereophony: phase, intensity differencephase, intensity difference 定位能力差：定位能力差：方向前後相反，距離高估方向前後相反，距離高估

Detect motion of a sound Detect motion of a sound MAMA (Minimum Audible Movement Angle)MAMA (Minimum Audible Movement Angle)

depend ondepend on Speed of movementSpeed of movement Initial position: Initial position: 正前方正前方 (0(0ºº)):: 5 5º, º, 側邊側邊 (90º)(90º) ：：

33º33º

較視覺差較視覺差 － End

Auditory DisplayAuditory Display —— Principles Principles 1/31/3 P. 176P. 176 Fig 6-9Fig 6-9

General PrinciplesGeneral Principles Compatibility Compatibility (e.g. high freq: up)(e.g. high freq: up)

Approximation: Approximation: two-stage signalstwo-stage signals Attention-demanding signalAttention-demanding signal Designation signalDesignation signal

DissociabilityDissociability Discernible from any ongoing audio inputDiscernible from any ongoing audio input

ParsimonyParsimony InvarianceInvariance

Auditory DisplayAuditory Display —— Principles Principles 2/32/3

P. 176P. 176 Fig 6-9Fig 6-9

Principles of PresentationPrinciples of Presentation Avoid extremes of auditory dimensionsAvoid extremes of auditory dimensions

(e.g.) startle response(e.g.) startle response Establish intensity relative to ambient noise levelEstablish intensity relative to ambient noise level

Not maskedNot masked Use interrupted or variable signalsUse interrupted or variable signals

Adaptation Adaptation Do not overload the auditory channelDo not overload the auditory channel

Auditory DisplayAuditory Display —— Principles Principles 3/33/3

P. 176P. 176 Fig 6-9Fig 6-9

Principles of Installation of Auditory Principles of Installation of Auditory DisplaysDisplays Test signals to be usedTest signals to be used

Representative sample of potential user populationRepresentative sample of potential user population

Avoid conflict with previously used signalsAvoid conflict with previously used signals

Facilitate changeover from previous displayFacilitate changeover from previous display

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Auditory DisplayAuditory Display —Specific —Specific Purpose Purpose 1/31/3

Warning & Alarm SignalsWarning & Alarm Signals 聽覺特別適合聽覺特別適合 那一種聲音較適合 那一種聲音較適合 Fig 6-10Fig 6-10 6-126-12

Intensity: Intensity: Fig 6-11Fig 6-11

SRT: SRT: 強強 , CRT: , CRT: 中等中等 Recommendations P.180Recommendations P.180

Auditory DisplayAuditory Display —Specific —Specific Purpose Purpose 2/32/3

Warning & Alarm SignalsWarning & Alarm Signals Recommendations P.180Recommendations P.180

200 – 5000 Hz200 – 5000 Hz

Travel long distance: below 1000 HzTravel long distance: below 1000 Hz

Bend around obstacles: below 500 HzBend around obstacles: below 500 Hz

Modulated signal: different enoughModulated signal: different enough

Frequency different from bk.Frequency different from bk.

If different warning signals used: discriminable, moderatIf different warning signals used: discriminable, moderate-intensitye-intensity

Separate communication systemSeparate communication system

Auditory DisplayAuditory Display —Specific —Specific Purpose Purpose 3/33/3

Aids for the Blind (clear-path indicatorAids for the Blind (clear-path indicators)s) PathsounderPathsounder

Single-object sensorSingle-object sensor

Sonic pathfinderSonic pathfinder

須 須 walk more slowlywalk more slowly

問題問題

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Tactile Tactile DisplayDisplay

類型類型 : Mechanical vs. Electrical : Mechanical vs. Electrical Substitutes for Hearing Substitutes for Hearing Substitutes for Seeing Substitutes for Seeing Discussion Discussion

Tactile Display Tactile Display —Mechanical —Mechanical vs. vs. Electrical Electrical 1/21/2

CodingCoding

CodingCoding MechanicalMechanical ElectricalElectrical

LocationLocation FrequencyFrequency IntensityIntensity DurationDuration Phase Phase ？？

Tactile Display Tactile Display —Mechanical —Mechanical vs. vs. Electrical Electrical 2/22/2

Electrical Electrical ＞ ＞ MechanicalMechanical Less bulkLess bulk

Lower power requirementLower power requirement

Independent of skin temperatureIndependent of skin temperature

Electrical Electrical ＜ ＜ MechanicalMechanical Elicit painElicit pain

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Tactile DisplayTactile Display —Substitutes for —Substitutes for HearingHearing

Reception of Coded MessagesReception of Coded Messages 5(chest location) 5(chest location) × 3(intensity) × 3(duration)× 3(intensity) × 3(duration) =45 pattern (26 letters, 10 numbers, 4 words)=45 pattern (26 letters, 10 numbers, 4 words)

38 word/min 38 word/min ＞ ＞ Morse code (24 word/min)Morse code (24 word/min)

Perception of Speech (Perception of Speech (×)×) Localization of Sound: Localization of Sound: intensity differenceintensity difference

Ear (L&R): microphoneEar (L&R): microphone → →Index fingers: vibrators Index fingers: vibrators

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Tactile DisplayTactile Display —Substitutes for —Substitutes for Seeing Seeing 1/31/3

Identification of ControlIdentification of Control Coding: Shape, texture, sizeCoding: Shape, texture, size

Fig 6-14Fig 6-14

Reading Printed MaterialReading Printed Material Braille printing Braille printing (6(6 個位置個位置 : : 橫橫 22 縱縱 3)3)

Optacon: Optacon: Fig 6-15Fig 6-15

optical-to-tactile converteroptical-to-tactile converter

Tactile DisplayTactile Display —Substitutes for —Substitutes for Seeing Seeing 2/32/3

Navigation AidsNavigation Aids Environmental featuresEnvironmental features

Point featuresPoint features Linear features Linear features Fig 6-16Fig 6-16

Areal featuresAreal features Guide to use mapGuide to use map

Tactile Graphs Tactile Graphs Fig 6-17Fig 6-17

Incised-grid (bk) & raised lines: betterIncised-grid (bk) & raised lines: better Raised-grid (bk): Raised-grid (bk): OKOK

Tactile DisplayTactile Display —Substitutes for —Substitutes for Seeing Seeing 3/33/3

Tracking-Task displays Tracking-Task displays Fig 6-18Fig 6-18

Single-task:Single-task: ＋＋ quickening visual display≒quickening visual display≒ quickening: predictor displayquickening: predictor display

future consequences of a controlfuture consequences of a control

Dual-task:Dual-task:

visual-tactile (primary-secondary)visual-tactile (primary-secondary)

﹥﹥visual-visualvisual-visual

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Tactile DisplayTactile Display ——DiscussionDiscussion

可用於 可用於 visual, auditoryvisual, auditory Overburdened Overburdened 時時 BlindBlind

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Olfactory Sense Olfactory Sense 1/21/2

MechanismMechanism Receptors:Receptors:

鼻腔 鼻腔 olfactory cell olfactory cell 之 之 olfactory hairsolfactory hairs

Stimulus:Stimulus:

揮發性分子之部份揮發性分子之部份

Olfactory Sense Olfactory Sense 2/22/2

特性特性 High false-alarm rateHigh false-alarm rate

Absolute identification:Absolute identification: 15-32 15-32 種 種 odor (complex stimulus)odor (complex stimulus)

3-4 3-4 種強度種強度 Identification Identification 差差 :: 可能因字彙少可能因字彙少 Effective: detecting the Effective: detecting the presencepresence of an odor of an odor

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Olfactory Olfactory DisplayDisplay

缺點缺點 :: Reliability Reliability 差差 (( 例例 ) stuff nose; Adaptation ) stuff nose; Adaptation 快快 Control Control 難難

優點優點 :: 傳播易傳播易 用途用途 :: warningwarning

(( 例例 ) ) 瓦斯瓦斯 (gas), (gas), 礦坑礦坑 (mine)(mine)

防火系統防火系統 : CO: CO22 ＋冬青味＋冬青味 適用適用 :: closed space, vast areasclosed space, vast areas

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