Design of Visual Displays for Driving Simulator Research

G. John Andersen

Department of Psychology

University of California, Riverside

Vision Issues in Driving Simulators

• Driving tasks require accurate perception of depth and distance in the 3D scene– What sources of information are critical– Integration of sources– Conflict between sources

• Visual Display – Display characteristics (Aliasing, Flicker,

Update,Refresh, Resolution)

Failure to Consider these issues in Driving Simulators

• Poor task performance• Low external validity of results• Poor transfer of training• Increased risk of simulator sickness

Driving tasks and Perception of Depth and Distance

, 96

Cutting, 1996

Depth

Con

trast

Depth (meters)

Occlusion

1 10 100

Size constancy

Cast Shadows

Disparity

Motionparallax

Convergence

Aerial

Overall scene depth

Layout of Objects

Properties of Objects

Viewer-centered

Information

Accommodation

Linear Perspective

Disparity

Motion Parallax

Linear Perspective

Relative Size

Motion Parallax

Texture (perspective)

Specular Highlights

Object-centered

Information

Surrounding Frame

Compression Gradient

Structure from Motion

Compression Gradient

Structure from Motion

Texture (non-perspective)

Shading

Andersen, Braunstein, & Saidpour, 1998

Driving Tasks and Perception

• Multiple sources of information available for driving tasks– What information is critical for what tasks

• Multiple sources for a specific task• Different tasks require different information

sources

– Use of multiple sources• Cue interactions• Cue conflicts

Multiple sources for a specific task: Collision Detection

• Model based on analysis of visual information available to driver (Andersen & Sauer, 2004)– Use of 5 parameters

motion parallax; optic flow)

d/dt (motion parallax; optic flow)

d/dt

ds (texture gradients, disparity, relative size)

Front View Top View

t=1

t=0

specifies the time to contact during constant velocitycollisions

a is the bearing of an object relative to a reference

ddt, dsd/dt, d/dt,

ddt, ds

ddt, ds

d/dt, d/dt, ddt, ds

ddtds ddt, ds

ddt, ds

d/dt, ds

ddt

d/dt, ddt, ds

d/dt, d/dt, d/dt, ds ddt

d/dt

d/dt, ddt, ds

d/dt, ddt, ds

d/dt, ddt, ds

d/dt, ddt, ds

d/dt, ddt, ds

d/dt, ddt, ds

Vehicle Motion

ObjectMotion

F = Fixed Speed V = Variable SpeedS = Straight Path C = Curved Path

No

F/S

V/S

F/C

V/C

No F/S V/S F/C V/C

Is =0? Or d/dt0?(constant angular

direction)

Is >0?(expansion)?

Yes

No

Yes

Is d/dt =0?(Constant expansion)

No

Derive

d/dt

Is d/dt >=-0.5?

No

Collision Object

Derivedv-ds

Is dv-ds >0?

Yes

Non-collision Object

Derive

Derive d/dt(angular direction)

Is dv-ds =0?(Constant expansion)

No

Yes

SelectObject

Different tasks and different sources of information

Two tasks with different sources of information

- Collision Detection (constant speeds and linear trajectories): Optical Expansion (TTC) and

-Vehicle Speed: Edge Rate

Question: Does information from one task affect use of information for second task

Experiment• Issue: Does information for one

task affect use of information for a different task

• Task: collision detection

• Independent Variables– Collision or non-collision object

– Time to contact (TTC)

– Different combinations of vehicle speed and object speed

• Dependent variable– Sensitivity (d’)

Vehicle / Object Velocity

d'

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

0/-0.8 0.2/-0.6 0.4/-0.4 0.2/-0.6

TTC 3.5 s

TTC 4.5 s

TTC 5.5 s

Simulators depict a 3D world

Perception of 3D scene includes-Texture gradients-Motion parallax-Occlusion-other information sources

Visual system also has cues for perceiving the distance to the display

3 Information sources for depth and distance of Display

- Binocular Disparity

- Eye convergence

- Accommodation

, 96

Cutting, 1996

Depth

Con

trast

Depth (meters)

Occlusion

1 10 100

Size constancy

Cast Shadows

Disparity

Motionparallax

Convergence

AerialAccommodation

Visual Cue Conflicts between display cues and 3D scene cues

Visual Cue conflict:

- Disparity, convergence and accommodation information specify display is flat

- Motion parallax, texture gradients, and other cues specify scene is 3D

Human Factors Solutions to these Issues

• Determine perceptual information needed for driving tasks of interest

• Design displays to optimize performance of tasks– Consider interactions of different information sources

• Minimize cue conflicts• Design for optimal performance not for high

fidelity– Question need of high fidelity rendered scenes, control

dynamics and fixed/variable base simulator