A COMPARATIVE STUDY OF SIMULATED AUGMENTED REALITY DISPLAYS FOR

VEHICLE NAVIGATION Richie Jose1, Gun Lee2, Mark Billinghurst2

1HIT Lab NZ, University of Canterbury 2Empathic Computing Lab, Univ. of South Australia

November 30th 2016 OzCHI 2016

AR for In-Car Navigation

Windshield Display (HUD)

Console Display (HDD)

Head Mounted Display (HMD)

Interface Trade-Offs • Head Down Display

•  Doesn’t obstruct view •  Clear virtual image •  Eyes move off the road

• Head Up Display •  Large field of view •  Reduces eye time off road •  Obstruction of real world

• Head Mounted Display •  Information always in view •  Blocks driver view

Comparative Studies • Which AR interface is best for drivers?

• HUD AR vs. HDD AR • Many studies • HUD users more time with eyes on road

•  Faster reaction time, fewer driver errors

• HDD AR vs. HDD non-AR • AR HDD more understandable

• HDD AR vs. HUD AR vs. HMD AR • No comparative studies

Simulated AR Driving Interface

• DK-1 HMD, steering wheel •  3D city model • Driving simulation • Simulated AR interface

•  direction, speed, gear

Simulated Interfaces

•  safs

Windshield - HUD

Console - HDD

Wearable Computer - HMD

Demo: AR HUD

Demo: AR HDD

Demo: AR HMD

Experiment Design • Participants

•  18 participants (14 male) aged 20 - 35 years (Mean: 25.5 yrs)

• Participants drive path performing three tasks: 1.  Follow navigational instructions on the display 2.  Keep to the speed limit of 60km/h 3.  Look around for virtual characters in the scene

• Conditions • HUD vs. HDD vs. HMD • Within subjects design

Experimental Measures • Objective

• Number of navigational errors • Number of wrong turns make •  Time driving over speed limit • Number of characters spotted (out of 20)

• Subjective • Questionnaire on comfort, usability and efficiency • Rank the three conditions based on user preference

Subjective Questionnaire

•  Likert scale - 1 (totally disagree) to 7 (totally agree)

Results

• Objective Results • HUD produced the fewest navigational errors • Participants exceeded the speed limit most in the HDD

• Subjective Results • HUD scored significantly better for most of the questions • HUD ranked as the most preferred and the HMD as the least

Navigational Error

• Ratio of incorrect to correct turns • Significantly fewer wrong turn errors in HUD condition

Time Spent Speeding (> 62 km/hr)

• Significantly more in HDD condition • No difference between HUD and HMD conditions

Number of Virtual Characters Spotted

• Significant difference between HUD and HDD • No difference between other conditions

Qualitative Results

• Significant difference between •  display visibility (Q2) – HUD best •  how distracting display was (Q3) – HUD best •  ease of navigation (Q4) – HUD best •  helps in multitasking (Q5) – HUD best •  useful for navigating (Q6) – HUD better than HMD •  comfortable using display (Q7) – HUD better than HMD

Ranking Results • Rank displays in the order of preference

•  1 = the best to 3 = the worst

• Median Rankings • HUD display first (Median [IQR] = 1 [1-1.75]) • HDD took the second place (2 [2-2.75]) • HMD was ranked as the worst (3 [2-3])

• HUD ranked significantly better than HDD and HMD, no difference between HDD and HMD

Participant Feedback • HUD

•  visibility as the main advantage •  “simple and easily visible”

•  display fixed in the space is a positive feature

• HDD •  simple and familiar to use •  disadvantage of not being within the primary task space

•  “(it) required me to look down and take eyes off the road”

• HMD •  display following the view was the main advantage

•  “easy to see even when ... not looking forward” •  main problem was HMD position

•  “difficult to focus on the display and the real world at the same time”

Discussion • User driving affected by the type of AR display

• HDD required looking down, HMD require refocusing

• Reduction in errors in HDD compared to HMD • HMD requires people to mentally remap instructions

• HDD produces more speeding • Eyes off road, hard to notice warnings

• Limitations • Not true AR view – graphics not fixed to world • Display size was same – HUD/HMD could be much bigger •  Interface layout was same

Conclusion • One of first comparative study of AR HUD, HMD and HDD navigation aids in a driving simulator

• HUD •  better driving, fewer errors, preferred over HDD/HMD

• HMD •  same errors as HDD, less speeding than HDD, ranked worst

• Future work • Stereo HMD, better interface design • World aligned AR cues • Real world implementation and testing

www.empathiccomputing.org

@marknb00

mark.billinghurst@unisa.edu.au