Biomaterial Database

Direct measurement of the system latency of gaze-contingent displays. 2014

Daniel R Saunders, and Russell L Woods

Schepens Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, MA, 02114, USA, daniel_saunders@meei.harvard.edu.

Gaze-contingent displays combine a display device with an eyetracking system to rapidly update an image on the basis of the measured eye position. All such systems have a delay, the system latency, between a change in gaze location and the related change in the display. The system latency is the result of the delays contributed by the eyetracker, the display computer, and the display, and it is affected by the properties of each component, which may include variability. We present a direct, simple, and low-cost method to measure the system latency. The technique uses a device to briefly blind the eyetracker system (e.g., for video-based eyetrackers, a device with infrared light-emitting diodes (LED)), creating an eyetracker event that triggers a change to the display monitor. The time between these two events, as captured by a relatively low-cost consumer camera with high-speed video capability (1,000 Hz), is an accurate measurement of the system latency. With multiple measurements, the distribution of system latencies can be characterized. The same approach can be used to synchronize the eye position time series and a video recording of the visual stimuli that would be displayed in a particular gaze-contingent experiment. We present system latency assessments for several popular types of displays and discuss what values are acceptable for different applications, as well as how system latencies might be improved.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D010781	Photography	Method of making images on a sensitized surface by exposure to light or other radiant energy.	Photographies
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D003201	Computers	Programmable electronic devices designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.	Calculators, Programmable,Computer Hardware,Computers, Digital,Hardware, Computer,Calculator, Programmable,Computer,Computer, Digital,Digital Computer,Digital Computers,Programmable Calculator,Programmable Calculators
D003626	Data Display	The visual representation of data via a manufactured system.	Information Display,Data Displays,Display, Data,Display, Information,Displays, Data,Displays, Information,Information Displays
D005133	Eye Movements	Voluntary or reflex-controlled movements of the eye.	Eye Movement,Movement, Eye,Movements, Eye
D005403	Fixation, Ocular	Positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.	Focusing, Ocular,Ocular Fixation,Eye Gaze,Eye Gazes,Gaze, Eye,Gazes, Eye,Ocular Focusing
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012607	Scotoma	A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.	Scotoma, Arcuate,Scotoma, Bjerrum,Scotoma, Central,Scotoma, Centrocecal,Scotoma, Altitudinal,Scotoma, Paracecal,Scotoma, Paracentral,Scotoma, Peripheral,Scotoma, Ring,Scotoma, Scintillating,Scotoma, Sector,Altitudinal Scotoma,Altitudinal Scotomas,Arcuate Scotoma,Arcuate Scotomas,Bjerrum Scotoma,Bjerrum Scotomas,Central Scotoma,Central Scotomas,Centrocecal Scotoma,Centrocecal Scotomas,Paracecal Scotoma,Paracecal Scotomas,Paracentral Scotoma,Paracentral Scotomas,Peripheral Scotoma,Peripheral Scotomas,Ring Scotoma,Ring Scotomas,Scintillating Scotoma,Scintillating Scotomas,Scotomas,Scotomas, Altitudinal,Scotomas, Arcuate,Scotomas, Bjerrum,Scotomas, Central,Scotomas, Centrocecal,Scotomas, Paracecal,Scotomas, Paracentral,Scotomas, Peripheral,Scotomas, Ring,Scotomas, Scintillating,Scotomas, Sector,Sector Scotoma,Sector Scotomas
D013996	Time and Motion Studies	The observation and analysis of movements in a task with an emphasis on the amount of time required to perform the task.	Time Studies,Studies, Time,Study, Time,Time Study