Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Upcoming SlideShare
What to Upload to SlideShare
What to Upload to SlideShare
Loading in …3
×
1 of 105

Comp4010 2021 Lecture2-Perception

3

Share

Download to read offline

Lecture 2 of the COMP 4010 class on AR/VR. This lecture is about the human perception system. This lecture was given on August 3rd 2021 by Mark Billinghurst from the University of South Australia.

Related Books

Free with a 30 day trial from Scribd

See all

Comp4010 2021 Lecture2-Perception

  1. 1. PERCEPTION COMP 4010 Lecture Two Mark Billinghurst August 3rd 2021 mark.billinghurst@unisa.edu.au
  2. 2. REVIEW
  3. 3. The Incredible Disappearing Computer 1960-70’s Room 1970-80’s Desk 1980-90’s Lap 1990-2000’s Hand 2010 - Head
  4. 4. Rekimoto, J. and Nagao, K. 1995. The world through the computer: computer augmented interaction with real world environments. Making Interfaces Invisible (c) Internet of Things
  5. 5. Internet of Things (IoT).. • Embed computing and sensing in real world • Smart objects, sensors, etc.. (c) Internet of Things
  6. 6. Virtual Reality (VR) • Users immersed in Computer Generated environment • HMD, gloves, 3D graphics, body tracking
  7. 7. Augmented Reality (AR) • Virtual Images blended with the real world • See-through HMD, handheld display, viewpoint tracking, etc..
  8. 8. AR vs VR
  9. 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. 10. Extended Reality (XR) Augmented Reality Virtual Reality Real World Virtual World Mixed Reality Extended Reality Internet of Things
  11. 11. Metaverse Components • Four Key Components • Virtual Worlds • Augmented Reality • Mirror Worlds • Lifelogging
  12. 12. History Timeline https://immersivelifeblog.files.wordpress.com/2015/04/vr_history.jpg
  13. 13. Ivan Sutherland (1960s) 1 3 Ivan Sutherland’s Head-Mounted Display (1968)
  14. 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. 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. 16. First Industrial Use of 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. 17. Desktop VR - 1995 • Expensive - $150,000+ • 2 million polys/sec • VGA HMD – 30 Hz • Magnetic tracking
  18. 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. 19. Rise of Commercial VR 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. 20. Mobile Phone AR (2005) • Mobile Phones • camera • processor • display • AR on Mobile Phones • Simple graphics • Optimized computer vision • Collaborative Interaction
  21. 21. 2008 - Browser BasedAR • 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. 22. 2008: Location Aware Phones Nokia Navigator Motorola Droid
  23. 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. 24. Desktop VR in 2016 • Graphics Desktop • $1,500 USD • >4 Billion poly/sec • $600 HMD • 1080x1200, 90Hz • Optical tracking • Room scale
  25. 25. Oculus Rift Sony Morpheus HTC/Valve Vive 2016 - Rise of Consumer HMDs
  26. 26. Social Mobile Camera AR Apps (2015 - ) • SnapChat - Lenses, World Lenses • Cinco de Mayo lens > 225 million views • Facebook - Camera Effects • Google – Word Lens/Translate
  27. 27. Hololens (2016) • Integrated system – Windows • Stereo see-through display • Depth sensing tracking • Voice and gesture interaction • Note: Hololens2 coming September 2019
  28. 28. ARKit/ARcore (2017) • Visual Inertial 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. 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. 30. THE BUSINESS OF AR/VR
  31. 31. Why 2021 won’t be 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. 32. Example: Pokemon GO Killer Combo: brand + social + mobile + geo-location + AR
  33. 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. 34. Augmented Reality in 2021 • 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
  35. 35. Large Growing Industry
  36. 36. Conclusion • AR/VR has a 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?
  37. 37. CONCLUSIONS
  38. 38. Conclusions • Mixed Reality continuum • 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
  39. 39. PERCEPTION
  40. 40. What is Reality?
  41. 41. How do We Perceive Reality? • We understand the world through our senses: • Sight, Hearing, Touch, Taste, Smell (and others..) • Two basic processes: • Sensation – Gathering information • Perception – Interpreting information
  42. 42. Simple Sensing/Perception Model
  43. 43. Goal of Virtual Reality “.. to make it feel like you’re actually in a place that you are not.” Palmer Luckey Co-founder, Oculus
  44. 44. Creating the Illusion of Reality • Fooling human perception by using technology to generate artificial sensations • Computer generated sights, sounds, smell, etc
  45. 45. Reality vs. Virtual Reality • In a VR system there are input and output devices between human perception and action
  46. 46. Example Birdly - http://www.somniacs.co/ • Create illusion of flying like a bird • Multisensory VR experience • Visual, audio, wind, haptic
  47. 47. Birdly Demo • https://www.youtube.com/watch?v=gHE6H62GHoM
  48. 48. PRESENCE
  49. 49. Presence .. “The subjective experience 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.
  50. 50. 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.
  51. 51. How to Create Strong 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)
  52. 52. Five Key Technical Requirements 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/
  53. 53. Example: UNC Pit Room • 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/
  54. 54. Typical Subject Behaviour • Note – from another pit experiment • https://www.youtube.com/watch?v=VVAO0DkoD-8
  55. 55. Richie’s Plank • https://www.youtube.com/watch?v=4M92kfnpg-k
  56. 56. Benefits of High Presence • 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
  57. 57. Measuring Presence • Presence is 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
  58. 58. 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
  59. 59. Object Presence • What makes an object appear real? • Touch/Haptic feedback • Appearance • Lighting • Audio cues • Occlusion • Etc..
  60. 60. Social Presence • What makes 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.
  61. 61. PERCEPTION
  62. 62. Motivation • Understand: In order 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
  63. 63. Senses • How an organism 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)
  64. 64. Relative Importance of Each 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
  65. 65. Other Lessor Known Senses.. • 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
  66. 66. Sight
  67. 67. The Human Visual System • Purpose is to convert visual input to signals in the brain
  68. 68. The Human Eye • Light passes through cornea and lens onto retina • Photoreceptors in retina convert light into electrochemical signals
  69. 69. Photoreceptors – Rods and 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
  70. 70. Human Horizontal and Vertical 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
  71. 71. Vergence + Accommodation • saas
  72. 72. Vergence/Accommodation Demo • https://www.youtube.com/watch?v=p_xLO7yxgOk
  73. 73. Vergence-Accommodation Conflict • Looking at 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
  74. 74. Visual Acuity Visual Acuity Test 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
  75. 75. Stereo Perception/Stereopsis • Eyes separated 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
  76. 76. Depth Perception • The visual 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
  77. 77. Common Depth Cues
  78. 78. Depth Perception Distances • i.e. convergence/accommodation used for depth perception < 10m
  79. 79. Properties of the Human 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
  80. 80. Creating the Perfect Illusion 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
  81. 81. Comparison between Eyes and HMD
  82. 82. Hearing
  83. 83. Anatomy of the Ear
  84. 84. Auditory Thresholds • Humans hear frequencies from 20 – 22,000 Hz • Most everyday sounds from 80 – 90 dB
  85. 85. Sound Localization • Humans have two ears • localize sound in space • Sound can be localized using 3 coordinates • Azimuth, elevation, distance
  86. 86. Sound Localization • https://www.youtube.com/watch?v=FIU1bNSlbxk
  87. 87. Sound Localization (Azimuth Cues) Interaural Time Difference
  88. 88. 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
  89. 89. Accuracy of Sound Localization • 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.
  90. 90. Touch
  91. 91. Haptic Sensation • Somatosensory System • 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
  92. 92. Cutaneous System • Skin – heaviest organ in the body • Epidermis outer layer, dead skin cells • Dermis inner layer, with four kinds of mechanoreceptors
  93. 93. Mechanoreceptors • Cells that respond 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
  94. 94. Spatial Resolution • Sensitivity varies 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
  95. 95. Proprioception/Kinaesthesia • Proprioception (joint position 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
  96. 96. www.empathiccomputing.org @marknb00 mark.billinghurst@auckland.ac.nz

×