Visual occlusion goggles

Liquid crystal goggles for measuring the visual demand of in-vehicle tasks with the occlusion method of ISO 16673:2017 and the NHTSA visual-manual driver distraction guidelines.

The ISO 16673 schedule, running in real time: 1.5 s clear, 1.5 s opaque. The demo trial ends at 12 s of total shutter open time, the NHTSA acceptance limit.

<10ms
Opening transition: ~50ms
Closing, to functional occlusion: 1ms
Timing resolution, on the controller: 2yr
Warranty

Method

In an occlusion test the participant works through a task on an in-vehicle interface while the lenses alternate between clear and opaque, 1.5 s each by default. The opaque intervals stand in for glances back to the road. The participant may keep operating the controls while the lenses are closed but can see neither the display nor the controls.

The test yields three measures, as ISO 16673 defines them:

Total shutter open time (TSOT): The sum of the open intervals the participant needs to complete the task.
Total task time unoccluded (TTT_Unoccl): The time to complete the same task with normal vision and no concurrent task.
Resumability ratio (R): TSOT divided by TTT_Unoccl. It indexes how readily the participant resumes the task after each interruption.

The NHTSA guidelines accept a task when at least 21 of 24 participants complete it with no more than 12 s of total shutter open time.

Specifications

Lenses	Polymer-dispersed liquid crystal (PDLC)
Opening transition	Under 10 ms, opaque to clear
Closing transition	About 50 ms to functional occlusion, about 100 ms to full opacity
Interval and TSOT timing	The controller times the intervals and accumulates TSOT itself, on a 1 ms clock. The host computer's timing does not affect either
Presets	NHTSA cycle, peek, direct control, custom
Control	USB serial. RSLogger, or open and close commands from your own software
Output	CSV with one row per trial: TSOT and total shutter closed time
Warranty	Two years

Kit contents

One pair of occlusion goggles with liquid crystal lenses
One controller box
Two participant response buttons

Software

The goggles run from RSLogger, which is included. Its VOG module sets the open and closed intervals and records the TSOT that the controller reports for each trial. The participant’s response button can start and stop the trial. RSLogger stamps each row with the same host clock it uses for cameras, the eye tracker and the DRT recorded in the same session.

VOG module documentation

RSLogger VOG module showing lens state over time — Fig. 2 RSLogger VOG module. The upper trace is lens state and the lower plot is TSOT and total shutter closed time per trial.

References

ISO. (2017). ISO 16673:2017 Road vehicles — Ergonomic aspects of transport information and control systems — Occlusion method to assess visual demand due to the use of in-vehicle systems. International Organization for Standardization.
NHTSA. (2013). Visual-Manual NHTSA Driver Distraction Guidelines for In-Vehicle Electronic Devices. 78 FR 24817. National Highway Traffic Safety Administration.
JAMA. (2004). Guidelines for In-vehicle Display Systems — Version 3.0. Japan Automobile Manufacturers Association.
SAE International. (2015). SAE J2364: Navigation and Route Guidance Function Accessibility While Driving.
Alliance of Automobile Manufacturers. (2006). Statement of Principles, Criteria and Verification Procedures on Driver Interactions with Advanced In-Vehicle Information and Communication Systems.

Ordering

Order the goggle kit

The complete kit carries a two-year warranty, and we ship worldwide. Tell us about your protocol and we will reply with a formal quote, usually within one business day.