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Comp4010 2021 Lecture2-Perception
This document provides a summary of a lecture on perception in augmented and virtual reality. It discusses the history of disappearing computers from room-sized to handheld. It reviews the key concepts of augmented reality, virtual reality, and mixed reality on Milgram's continuum. It discusses how perception of reality works through our senses and how virtual reality aims to create an illusion of reality. It covers factors that influence the sense of presence such as immersion, interaction, and realism.
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Comp4010 2021 Lecture2-Perception
- 1. PERCEPTION COMP 4010 LectureTwo Mark Billinghurst August 3rd 2021 mark.billinghurst@unisa.edu.au
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- 3. The Incredible DisappearingComputer 1960-70’s Room 1970-80’s Desk 1980-90’s Lap 1990-2000’s Hand 2010 - Head
- 4. Rekimoto, J. andNagao, K. 1995. The world through the computer: computer augmented interaction with real world environments. Making Interfaces Invisible (c) Internet of Things
- 5. Internet of Things(IoT).. • Embed computing and sensing in real world • Smart objects, sensors, etc.. (c) Internet of Things
- 6. Virtual Reality (VR) •Users immersed in Computer Generated environment • HMD, gloves, 3D graphics, body tracking
- 7. Augmented Reality (AR) •Virtual Images blended with the real world • See-through HMD, handheld display, viewpoint tracking, etc..
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- 9. Milgram’s Mixed Reality(MR) Continuum Augmented Reality Virtual Reality Real World Virtual World Mixed Reality "...anywhere between the extrema of the virtuality continuum." P. Milgram and A. F. Kishino, (1994) A Taxonomy of Mixed Reality Visual Displays Internet of Things
- 10. Extended Reality (XR) AugmentedReality Virtual Reality Real World Virtual World Mixed Reality Extended Reality Internet of Things
- 11. Metaverse Components • FourKey Components • Virtual Worlds • Augmented Reality • Mirror Worlds • Lifelogging
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- 13. Ivan Sutherland (1960s) 1 3 IvanSutherland’s Head-Mounted Display (1968)
- 14. Super Cockpit (1965-80’s) •US Airforce Research Program • Wright Patterson Air Force Base • Tom Furness III • Multisensory • Visual, auditory, tactile • Head, eye, speech, and hand input • Addressing pilot information overload • Flight controls and tasks too complicated • Research only • big system, not safe for ejecting
- 15. VPL Research (1985– 1999) • First Commercial VR Company • Jaron Lanier, Jean-Jacques Grimaud • Provided complete systems • Displays, software, gloves, etc • DataGlove, EyePhone, AudioSphere
- 16. First Industrial Useof AR (1990’s) • 1992: Tom Caudell at Boeing coined the term “AR.” • Wire harness assembly application begun • Lead by Tom Caudell, and David Mizell
- 17. Desktop VR -1995 • Expensive - $150,000+ • 2 million polys/sec • VGA HMD – 30 Hz • Magnetic tracking
- 18. Mobile/Wearable Systems (1995) •1995 Navicam (Rekimoto) • Handheld AR • 1997 Touring Machine (Feiner) • Backpack AR, GPS, see-through display • 1998 Tinmith (Thomas, UniSA) • Outdoor gaming, CAD
- 19. Rise of CommercialVR Companies • W Industries/Virtuality (1985 - 97) • Location based entertainment • Virtuality VR Arcades • Division (1989 – 1998) • Turn key VR systems • Visual programming tools • Virtual i-O (1993 -1997) • Inexpensive gamer HMDs • Sense8 (1990 - 1998) • WorldToolKit, WorldUp • VR authoring tools
- 20. Mobile Phone AR(2005) • Mobile Phones • camera • processor • display • AR on Mobile Phones • Simple graphics • Optimized computer vision • Collaborative Interaction
- 21. 2008 - BrowserBasedAR • Flash + camera + 3D graphics • ARToolKit ported to Flash • High impact • High marketing value • Large potential install base • 1.6 Billion web users • Ease of development • Lots of developers, mature tools • Low cost of entry • Browser, web camera
- 22. 2008: Location AwarePhones Nokia Navigator Motorola Droid
- 23. VR Second Wave(2010 - ) • Palmer Luckey • HMD hacker • Mixed Reality Lab (MxR) intern • Oculus Rift (2011 - ) • 2012 - $2.4 million kickstarter • 2014 - $2B acquisition FaceBook • $350 USD, 110o FOV
- 24. Desktop VR in2016 • Graphics Desktop • $1,500 USD • >4 Billion poly/sec • $600 HMD • 1080x1200, 90Hz • Optical tracking • Room scale
- 25. Oculus Rift Sony Morpheus HTC/ValveVive 2016 - Rise of Consumer HMDs
- 26. Social Mobile CameraAR Apps (2015 - ) • SnapChat - Lenses, World Lenses • Cinco de Mayo lens > 225 million views • Facebook - Camera Effects • Google – Word Lens/Translate
- 27. Hololens (2016) • Integratedsystem – Windows • Stereo see-through display • Depth sensing tracking • Voice and gesture interaction • Note: Hololens2 coming September 2019
- 28. ARKit/ARcore (2017) • VisualInertial Odometry (VIO) systems • Mobile phone pose tracked by • Camera (Visual), Accelerometer & Gyroscope (Intertial) • Features • Plane detection, lighting detection, hardware optimisation • Links • https://developer.apple.com/arkit/ • https://developers.google.com/ar/
- 29. History Summary • 1960’s– 80’s: Early Experimentation • 1980’s – 90’s: Basic Research • Tracking, displays • 1995 – 2005: Tools/Applications • Interaction, usability, theory • 2005 - : Commercial Applications • Mobile, Games, Medical, Industry
- 30. THE BUSINESS OFAR/VR
- 31. Why 2021 won’tbe like 1996 • It’s not just VR anymore • Huge amount of investment • Inexpensive hardware platforms • Easy to use content creation tools • New devices for input and output • Proven use cases – no more Hype! • Most important: Focus on User Experience
- 32. Example: Pokemon GO KillerCombo: brand + social + mobile + geo-location + AR
- 33. Pokemon GO Effect •Fastest App to reach $500 million in Revenue • Only 63 days after launch, > $1 Billion in 6 months • Over 500 million downloads, > 25 million DAU • Nintendo stock price up by 50% (gain of $9 Billion USD)
- 34. Augmented Reality in2021 • Large growing market • > $7Billion USD in 2020 • Many available devices • HMD, phones, tablets, HUDs • Robust developer tools • Vuforia, ARToolKit, Unity, Wikitude, etc • Large number of applications • > 150K developers, > 100K mobile apps • Strong research/business communities • ISMAR, AWE conferences, AugmentedReality.org, etc
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- 42. Conclusion • AR/VR hasa long history • > 50 years of HMDs, simulators • Key elements for were in place by early 1990’s • Displays, tracking, input, graphics • Strong support from military, government, universities • First commercial wave failed in late 1990’s • Too expensive, bad user experience, poor technology, etc • We are now in second commercial wave • Better experience, Affordable hardware • Large commercial investment, Significant installed user base • Will XR be a commercial success this time?
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- 44. Conclusions • Mixed Realitycontinuum • AR/VR complimentary technologies • Key Enabling Technologies • Display, Interaction, Tracking • Many possible applications • Industry, Education, Medicine, etc. • Rapidly growing market • Many areas for commercial application
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- 47. How do WePerceive Reality? • We understand the world through our senses: • Sight, Hearing, Touch, Taste, Smell (and others..) • Two basic processes: • Sensation – Gathering information • Perception – Interpreting information
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- 49. Goal of VirtualReality “.. to make it feel like you’re actually in a place that you are not.” Palmer Luckey Co-founder, Oculus
- 50. Creating the Illusionof Reality • Fooling human perception by using technology to generate artificial sensations • Computer generated sights, sounds, smell, etc
- 51. Reality vs. VirtualReality • In a VR system there are input and output devices between human perception and action
- 52. Example Birdly -http://www.somniacs.co/ • Create illusion of flying like a bird • Multisensory VR experience • Visual, audio, wind, haptic
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- 55. Presence .. “The subjectiveexperience of being in one place or environment even when physically situated in another” Witmer, B. G., & Singer, M. J. (1998). Measuring presence in virtual environments: A presence questionnaire. Presence: Teleoperators and virtual environments, 7(3), 225-240.
- 56. Immersion vs. Presence •Immersion: describes the extent to which technology is capable of delivering a vivid illusion of reality to the senses of a human participant. • Presence: a state of consciousness, the (psychological) sense of being in the virtual environment. • So Immersion, defined in technical terms, is capable of producing a sensation of Presence • Goal of VR: Create a high degree of Presence • Make people believe they are really in Virtual Environment Slater, M., & Wilbur, S. (1997). A framework for immersive virtual environments (FIVE): Speculations on the role of presence in virtual environments. Presence: Teleoperators and virtual environments, 6(6), 603-616.
- 57. How to CreateStrong Presence? • Use Multiple Dimensions of Presence • Create rich multi-sensory VR experiences • Include social actors/agents that interact with the user • Have environment respond to the user • What Influences Presence • Vividness – ability to provide rich experience (Steuer 1992) • Using Virtual Body – user can see themselves (Slater 1993) • Internal factors – individual user differences (Sadowski 2002) • Interactivity – how much users can interact (Steuer 1992) • Sensory, Realism factors (Witmer 1998)
- 58. Five Key TechnicalRequirements for Presence • Persistence • > 90 Hz refresh, < 3 ms persistence, avoid retinal blur • Optics • Wide FOV > 90 degrees, comfortable eyebox, good calibration • Tracking • 6 DOF, 360 tracking, sub-mm accuracy, no jitter, good tracking volume • Resolution • Correct stereo, > 1K x 1K resolution, no visible pixels • Latency • < 20 ms latency, fuse optical tracking and IMU, minimize tracking loop http://www.roadtovr.com/oculus-shares-5-key-ingredients-for-presence-in-virtual-reality/
- 59. Example: UNC PitRoom • Key Features • Training room and pit room • Physical walking • Fast, accurate, room scale tracking • Haptic feedback – feel edge of pit, walls • Strong visual and 3D audio cues • Task • Carry object across pit • Walk across or walk around • Dropping virtual balls at targets in pit • http://wwwx.cs.unc.edu/Research/eve/walk_exp/
- 60. Typical Subject Behaviour •Note – from another pit experiment • https://www.youtube.com/watch?v=VVAO0DkoD-8
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- 62. Benefits of HighPresence • Leads to greater engagement, excitement and satisfaction • Increased reaction to actions in VR • People more likely to behave like in the real world • E.g. people scared of heights in real world will be scared in VR • More natural communication (Social Presence) • Use same cues as face-to-face conversation • Note: The relationship between Presence and Performance is unclear – still an active area of research
- 63. Measuring Presence • Presenceis very subjective so there is a lot of debate among researchers about how to measure it • Subjective Measures • Self report questionnaire • University College London Questionnaire (Slater 1999) • Witmer and Singer Presence Questionnaire (Witmer 1998) • ITC Sense Of Presence Inventory (Lessiter 2000) • Continuous measure • Person moves slider bar in VE depending on Presence felt • Objective Measures • Behavioural • reflex/flinch measure, startle response • Physiological measures • change in heart rate, skin conductance, skin temperature Presence Slider
- 64. Types of Presence •Spatial Presence • Feeling that you are in another space • Object Presence • Feeling that an object is really in your space • Social Presence • Feeling that someone is really with you
- 65. Object Presence • Whatmakes an object appear real? • Touch/Haptic feedback • Appearance • Lighting • Audio cues • Occlusion • Etc..
- 67. Social Presence • Whatmakes a Person appear real? • Interactivity • Visual appearance • Audio cues • Touch • Contextual cues • Etc.. Oh, C. S., Bailenson, J. N., & Welch, G. F. (2018). A systematic review of social presence: Definition, antecedents, and implications. Frontiers in Robotics and AI, 5, 114.
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- 70. Motivation • Understand: Inorder to create a strong sense of Presence we need to understand the Human Perception system • Stimulate: We need to be able to use technology to provide real world sensory inputs, and create the VR illusion VR Hardware Human Senses
- 71. Senses • How anorganism obtains information for perception: • Sensation part of Somatic Division of Peripheral Nervous System • Integration and perception requires the Central Nervous System • Five major senses (but there are more..): • Sight (Opthalamoception) • Hearing (Audioception) • Taste (Gustaoception) • Smell (Olfacaoception) • Touch (Tactioception)
- 72. Relative Importance ofEach Sense • Percentage of neurons in brain devoted to each sense • Sight – 30% • Touch – 8% • Hearing – 2% • Smell - < 1% • Over 60% of brain involved with vision in some way
- 73. Other Lessor KnownSenses.. • Proprioception = sense of body position • what is your body doing right now • Equilibrium = balance • Acceleration • Nociception = sense of pain • Temperature • Satiety (the quality or state of being fed or gratified to or beyond capacity) • Thirst • Micturition • Amount of CO2 and Na in blood
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- 75. The Human VisualSystem • Purpose is to convert visual input to signals in the brain
- 76. The Human Eye •Light passes through cornea and lens onto retina • Photoreceptors in retina convert light into electrochemical signals
- 77. Photoreceptors – Rodsand Cones • Retina photoreceptors come in two types, Rods and Cones • Rods – 125 million, periphery of retina, no colour detection, night vision • Cones – 4-6 million, center of retina, colour vision, day vision
- 78. Human Horizontal andVertical FOV • Humans can see ~135 o vertical (60 o above, 75 o below) • See up to ~ 210o horizontal FOV, ~ 115o stereo overlap • Colour/stereo in centre, Black & White/mono in periphery
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- 81. Vergence-Accommodation Conflict • Lookingat real objects, vergence and focal distance match • In VR, vergence and accommodation can miss-match • Focusing on HMD screen, but accommodating for virtual object behind screen
- 82. Visual Acuity Visual AcuityTest Targets • Ability to resolve details • Several types of visual acuity • detection, separation, etc • Normal eyesight can see a 50 cent coin at 80m • Corresponds to 1 arc min (1/60th of a degree) • Max acuity = 0.4 arc min
- 83. Stereo Perception/Stereopsis • Eyesseparated by IPD • Inter pupillary distance • 5 – 7.5cm (avge. 6.5cm) • Each eye sees diff. image • Separated by image parallax • Images fused to create 3D stereo view
- 85. Depth Perception • Thevisual system uses a range of different Stereoscopic and Monocular cues for depth perception Stereoscopic Monocular eye convergence angle disparity between left and right images diplopia eye accommodation perspective atmospheric artifacts (fog) relative sizes image blur occlusion motion parallax shadows texture Parallax can be more important for depth perception! Stereoscopy is important for size and distance evaluation
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- 87. Depth Perception Distances •i.e. convergence/accommodation used for depth perception < 10m
- 88. Properties of theHuman Visual System • visual acuity: 20/20 is ~1 arc min • field of view: ~200° monocular, ~120° binocular, ~135° vertical • resolution of eye: ~576 megapixels • temporal resolution: ~60 Hz (depends on contrast, luminance) • dynamic range: instantaneous 6.5 f-stops, adapt to 46.5 f-stops • colour: everything in CIE xy diagram • depth cues in 3D displays: vergence, focus, (dis)comfort • accommodation range: ~8cm to ∞, degrades with age
- 89. Creating the PerfectIllusion Cuervo, E., Chintalapudi, K., & Kotaru, M. (2018, February). Creating the perfect illusion: What will it take to create life-like virtual reality headsets?. In Proceedings of the 19th International Workshop on Mobile Computing Systems & Applications (pp. 7-12). • Technology to create life-like VR HMDs • Compared to current HMDs • 6 − 10× higher pixel density • 20 − 30× higher frame rate
- 90. Comparison between Eyesand HMD
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- 93. Auditory Thresholds • Humanshear frequencies from 20 – 22,000 Hz • Most everyday sounds from 80 – 90 dB
- 94. Sound Localization • Humanshave two ears • localize sound in space • Sound can be localized using 3 coordinates • Azimuth, elevation, distance
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- 96. Sound Localization (AzimuthCues) Interaural Time Difference
- 97. HRTF (Elevation Cue) •Pinna and head shape affect frequency intensities • Sound intensities measured with microphones in ear and compared to intensities at sound source • Difference is HRTF, gives clue as to sound source location
- 98. Accuracy of SoundLocalization • People can locate sound • Most accurately in front of them • 2-3° error in front of head • Least accurately to sides and behind head • Up to 20° error to side of head • Largest errors occur above/below elevations and behind head • Front/back confusion is an issue • Up to 10% of sounds presented in the front are perceived coming from behind and vice versa (more in headphones) BUTEAN, A., Bălan, O., NEGOI, I., Moldoveanu, F., & Moldoveanu, A. (2015). COMPARATIVE RESEARCH ON SOUND LOCALIZATION ACCURACY IN THE FREE-FIELD AND VIRTUAL AUDITORY DISPLAYS. InConference proceedings of» eLearning and Software for Education «(eLSE)(No. 01, pp. 540-548). Universitatea Nationala de Aparare Carol I.
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- 100. Haptic Sensation • SomatosensorySystem • complex system of nerve cells that responds to changes to the surface or internal state of the body • Skin is the largest organ • 1.3-1.7 square m in adults • Tactile: Surface properties • Receptors not evenly spread • Most densely populated area is the tongue • Kinesthetic: Muscles, Tendons, etc. • Also known as proprioception
- 101. Cutaneous System • Skin– heaviest organ in the body • Epidermis outer layer, dead skin cells • Dermis inner layer, with four kinds of mechanoreceptors
- 102. Mechanoreceptors • Cells thatrespond to pressure, stretching, and vibration • Slow Acting (SA), Rapidly Acting (RA) • Type I at surface – light discriminate touch • Type II deep in dermis – heavy and continuous touch Receptor Type Rate of Acting Stimulus Frequency Receptive Field Detection Function Merkel Discs SA-I 0 – 10 Hz Small, well defined Edges, intensity Ruffini corpuscles SA-II 0 – 10 Hz Large, indistinct Static force, skin stretch Meissner corpuscles RA-I 20 – 50 Hz Small, well defined Velocity, edges Pacinian corpuscles RA-II 100 – 300 Hz Large, indistinct Acceleration, vibration
- 103. Spatial Resolution • Sensitivityvaries greatly • Two-point discrimination Body Site Threshold Distance Finger 2-3mm Cheek 6mm Nose 7mm Palm 10mm Forehead 15mm Foot 20mm Belly 30mm Forearm 35mm Upper Arm 39mm Back 39mm Shoulder 41mm Thigh 42mm Calf 45mm http://faculty.washington.edu/chudler/chsense.html
- 104. Proprioception/Kinaesthesia • Proprioception (jointposition sense) • Awareness of movement and positions of body parts • Due to nerve endings and Pacinian and Ruffini corpuscles at joints • Enables us to touch nose with eyes closed • Joints closer to body more accurately sensed • Users know hand position accurate to 8cm without looking at them • Kinaesthesia (joint movement sense) • Sensing muscle contraction or stretching • Cutaneous mechanoreceptors measuring skin stretching • Helps with force sensation
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