Techniques of perception with x3d
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Techniques of Perception with X3D. Nicholas F. Polys Luciano Pereira Soares. Session Outline. Polys Perception for Design Visualization Soares Immersion and Perception Polys Information-Rich Environments. Perception for Design.

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Techniques of perception with x3d

Techniques of Perception with X3D

Nicholas F. Polys

Luciano Pereira Soares

Web3D Symposium 2005

Session outline

Session Outline

  • Polys

    • Perception for Design

    • Visualization

  • Soares

    • Immersion and Perception

  • Polys

    • Information-Rich Environments

Web3D Symposium 2005

Perception for design

Perception for Design

  • Using our understanding of the human perceptual systems to guide design

    • Visual system

    • Auditory system

    • Vestibular system

  • Leverage pre-attentive facilities

  • Reduce cognitive overhead

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Background information psychophysics

Background:Information Psychophysics

  • Edward Tufte, Envisioning Information

    (1983, 1990)

  • Jaques Bertin, Semiology of Graphics


  • Donald Norman, Cognitive Engineering


  • Joseph Goguen, Semiotic Morphisms


  • Colin Ware, Perception for Design


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Pre attentive processing

Pre-attentive Processing

  • Involuntary, do not require conscious attention

  • Parallel

  • Efficient

  • Resistant to instruction

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Visual fields

Visual Fields


Useful Field of View

Field of View

Field of Regard

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Frame rate

Frame Rate

  • Threshold for perceiving continuity:

    • flicker < 50 Hz

    • > 24 fps looks smooth & plenty interactive

  • Flicker & Attention can lead to change blindness (Simmons, 2000)

  • Browser.getCurrentFrameRate()

  • Implementing X3DPerFrameObserverScript

    - public void prepareEvents (){}

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Graphics and vision

Graphics and Vision


  • Bottom-up : internal representations are built out of simple external properties

  • Top-down : hypotheses, expectations

    Perceptual processes are influenced by both; top-down processes take over for ambiguous or degraded stimuli

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Graphics and vision bottom up

Graphics and Vision: bottom-up

  • Objects – integration, recognition, working memory and reasoning

  • Patterns – contours, regions, groups; Gestalt

  • Features – color, texture, stereoscopic depth, shape & form, some aspects of motion

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Features color

Features: Color

  • Luminance channel

    (3x spatial accuity)

  • Red / Green channel

  • Yellow / Blue channel

    The spectrum is not a

    perceptually linear sequence

    (not pre-attentive)!

    (Keller 1993; Ware, 2000)

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Shapes appearances

Shapes & Appearances

  • Appearance {} and Materials {} : specular, emissive, and diffuse Colors in RGB, shininess, transparency, ambientIntensity

  • creaseAngle: shading across polygons edges of the mesh

  • normals (for shape-dependent lighting control)

  • colorPerVertex

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Rgb material

RGB Material {}


0.678, 0.169, 0.07



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  • ImageTexture {} with (or without) alpha channels can be applied and mapped to geometry as fixed or animated maps. 

    • Standard formats: .png, .jpg,

  • MovieTexture {}

  • TextureTransform {} …

  • PixelTexture {}

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MultiTexture {}

Blending operations specified via

mode field

Base Texture

+ Lightmap                  

= Result

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Lighting Nodes: on, intensity, ambientIntensity, color

  • Pointlight {attenuation}

  • DirectionalLight {}

  • Spotlight {direction, beamWidth, cutOffAngle}

  • AMD 1: SFBool global

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Features depth

Features: Depth

  • Occlusion

  • Motion Parallax

  • Linear Perspective

    • Relative size

    • Texture & shade gradients

  • Stereoscopy

  • Oculormotor cues

  • Transform {translation rotation}

  • Head-Up-Display / Imageplane

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Patterns grouping

Patterns & Grouping

  • Gestalt principles

  • Also: continuation, closure, common fate

  • Guiding Law of Pragnanz (simplest, most stable configuration)

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Gestalt principles

Gestalt principles

  • Palmer & Rock, 1990– review & update principles; grouping based on perceived proximity in 3D space (not 2D proximity on retina)

  • Quinlan & Wilton, 1998 – study involving Gestalt conflict; proposed resolution mechanisms

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  • Feature Binding – putting the streams together for internal represenation

    • color, form, motion

    • Just in time?

  • 2.5 D sketch (Marr, 1982)

  • Geons (Biederman, 1993)

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  • Pop out effects ‘stand out’ in some simple dimension (conjunctions don’t):

    • Rapid visual search

    • Form, color, simple motion/blinking, spatial stereo depth, shading, position


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Techniques of perception with x3d

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Fundamental data types

Fundamental Data Types

  • Spatial / perceptual data:

    geometry, colors, textures, lighting

  • Abstract data / world & object attributes: nominal, ordinal, quantitative

  • Temporal data / behaviors:

    states, dynamics

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Visual markers

Data Type




Graphical Representation



angle / slope



color / density

(Cleveland and McGill, 1980)












(Mackinlay, 1986)













(Mackinlay, 1986)

Visual Markers

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Techniques of perception with x3d

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Auditory perception

Auditory Perception

  • Sound {}

  • AudioClip {}

  • MovieTexture {}

    • pitch

    • intensity

    • Spatialized Audio (doppler effect)

    • Standard formats: .wav, .midi, .mp3, mpeg-1

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Existential perception

Existential Perception

What is my relation to this environment?

What can I do in this world?

What do my senses tell me?

  • Viewpoint {fieldOfView}

  • NavigationInfo {avatarSize, headlight, visibilityLimit, type, speed}

  • Timesensor {cycleInterval }

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Environmental effects

Environmental effects

  • Background {}: colors and textures give a context for the environment

  • TextureBackground {transparency }

  • Fog {type color visibilityRange}

  • LocalFog {} &

    FogCoordinate {}

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  • Luciano

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Information rich virtual environments irves

Information-Rich Virtual Environments (IRVEs)

We need to understand:

  • How spatial/perceptual information and abstract information can be combined and displayed

  • What makes the combinations effective

  • What makes them usable and

  • How users think and act when using them

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Multimedia comprehension

Multimedia & Comprehension

  • Co-references between text and images

    (Chandler & Sweller, 1990; Faraday & Sutcliffe, 1997, 1998)

  • Task Knowledge Structure

    (Sutcliffe & Faraday, 1994; Sutcliffe 2003)

  • Meaningful Learning: troubleshooting, redesigning, deriving principles

    (Mayer, 2002)

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Visualization annotation

Visualization & Annotation

  • Challenge to maintain perceptual fidelity

    • Scientific Visualization overloads color, texture to show abstract information

    • IRVEs attempt to maintain perceptual/spatial fidelity

  • Grouping, registering temporal and abstract information to referents

    • Visual

    • Interactive

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Layout space locations

Layout Space (Locations)

The layout space of abstract information in IRVEs is described by the coordinate system it is resident in:

  • Object

  • World

  • User

  • Viewport

  • Display

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Object space

Object Space

Object space is relative to an object’s location in the environment

(e.g. Semantic Objects).

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World space

World Space

World space is relative to an area, region, or location in the environment.

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User space

User Space

User space is relative to the user’s location but not their viewing angle.

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Viewport space

Viewport Space

Viewport space-is the image plane where HUDs or overlays may be located.

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Display space

Display Space

Display layout space where abstract visualizations are located outside the rendered view in some additional screen area.

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Working memory

Working Memory

How are the products of perception linked with memory and reasoning?

A number of models exist:

  • Baddeley’s componentized WM

  • Barnards’s Interacting Cognitive Subsystems

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Working memory baddeley 2003

Central Executive



Episodic buffer



Fluid system

Visual semantics Episodic LTM Language

Crystallized system

Working Memory (Baddeley, 2003)

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Visuospatial wm

Visuospatial WM

  • Capacity 3-5 ‘items’

  • Functional units & chunking

    • Objects & features (Vogel et al, 2001)

    • Visual indices & dynamic feature binding (Saiki, 2003)

  • Subsystems: form & color, space & movement (Logie 1995)

  • Relation to Central Executive

    (Miyake et al. 2001)

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Model ics interacting cognitive subsystems

Model ICS: Interacting Cognitive Subsystems








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Irves perception

IRVEs & Perception

  • Integrating information types via

    • Depth cues

    • Gestalt assocation cues

  • Recent studies examined search and comparison tasks:

    • the Viewport vs. Object space interfaces

    • The Display vs. Object space interfaces

  • Future work will investigate supporting pattern and trend recognition tasks

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Bertin, J., Semiology of Graphics. 1983, Madison, WI: University of Wisconsin Press.

Baddeley, A., Working memory: Looking back and looking forward. Nature Reviews Neuroscience, 2003. 4: p. 829-839.

Barnard, P., May, J., Duke, D., and Duce, D., Systems, interactions, and macrotheory. ACM Trans. on Computer-Human Interaction, 2000. 7(2): p. 222-262.

Biederman, I., and Gerhardstein, P.C., Recognizing depth-rotated objects: Evidence for 3-D viewpoint invariance. Journal of Experimental Psychology: Human Perception and Performance, 1993(19): p. 1162-1182.

Card, S., J. Mackinlay, and B. Shneiderman, Information Visualization: Using Vision to Think. 1999, San Francisco: Morgan Kaufmann.

Chandler, P., and Sweller, J., Cognitive Load Theory and the Format of Instruction. Cognition and Instruction, 1991. 8: p. 293-332.

Cleveland, W.S., and McGill, R., Graphical perception: Theory, experimentation and application to the development of graphical methods. J. Am. Stat. Assoc, 1984. 79(September).

Faraday, P., and Sutcliffe, Alistair. Designing Effective Multimedia Presentations. in CHI. 1997. Atlanta, GA: ACM.

Goguen, J., Information Visualizations and Semiotic Morphisms. 2000, UCSD:

Keller, P.R., Visual Cues: Practical Data Visualization. 1993, Piscataway, NJ: IEEE Computer Society Press.

Logie, R.H., Visuo-spatial working memory. 1995, Hove, UK: Psychology Press.

Mackinlay, J., Automating the Design of Graphical Presentations of Relational Information. ACM Trans. on Graphics, 1986. 5(2): p. 111-141.

Marr, D., Vision : a computational investigation into the human representation and processing of visual information. 1982, San Francisco: W.H. Freeman.

Mayer, R.E., Cognitive Theory and the Design of Multimedia Instruction: An Example of the Two-Way Street Between Cognition and Instruction. New Directions for Teaching and Learning, 2002. 89: p. 55-71.

Norman, D.A., Cognitive Engineering, in User Centered System Design, D.A. Norman, and Draper, S.D., Editor. 1986, Lawrence Erlbaum Associates: Hillsdale, NJ. p. 31-61.

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Techniques of perception with x3d


Pickett, R.M., Grinstein, G., Levkowitz, H., Smith, S., Harnessing Preattentive Perceptual Processes in Visualization, in Perceptual Issues in Visualization, G. Grinstein, and Levkoitz, H., Editor. 1995, Springer: New York.

Quinlan, P.T., and Wilton, R.N., Grouping by proximity or similarity? Competition between the Gestalt principles in vision. Perception, 1998. 27: p. 417-430.

Rock, I., and Palmer, S., The legacy of Gestalt psychology. Scientific American, 1990(December): p. 48-61.

Simmons, D.J., Attentional capture and inattentional blindness. Trends in Cognitive Sciences, 2000. 4: p. 147-155.

Sutcliffe, A., and Faraday, P. Designing Presentation in Multimedia Interfaces. in CHI. 1994: ACM Press.

Tufte, E., The Visual Display of Quantitative Information. 1983, Cheshire, CT: Graphics Press.

Tufte, E., Envisioning Information. 1990, Cheshire, CT: Graphics Press.

Ware, C., Information Visualization: Perception for Design. 2000, New York, NY: Morgan Kauffman.

Thanks to the ‘Rev.’ Bob Cripsen on his early instruction on VRML lighting!

Web3D Symposium 2005

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