ExpertEyes: Open-source, high-definition eyetracking

Abstract

ExpertEyes is a low-cost, open-source package of hardware and software that is designed to provide portable high-definition eyetracking. The project involves several technological innovations, including portability, high-definition video recording, and multiplatform software support. It was designed for challenging recording environments, and all processing is done offline to allow for optimization of parameter estimation. The pupil and corneal reflection are estimated using a novel forward eye model that simultaneously fits both the pupil and the corneal reflection with full ellipses, addressing a common situation in which the corneal reflection sits at the edge of the pupil and therefore breaks the contour of the ellipse. The accuracy and precision of the system are comparable to or better than what is available in commercial eyetracking systems, with a typical accuracy of less than 0.4° and best accuracy below 0.3°, and with a typical precision (SD method) around 0.3° and best precision below 0.2°. Part of the success of the system comes from a high-resolution eye image. The high image quality results from uncasing common digital camcorders and recording directly to SD cards, which avoids the limitations of the analog NTSC format. The software is freely downloadable, and complete hardware plans are available, along with sources for custom parts.

Characterizing Human Expertise Using Computational Metrics of Feature Diagnosticity in a Pattern Matching Task

“…These values are comparable to those of commercial systems, and more information about the calibration routines are found in Parada et al. (). One degree of visual angle is approximately two ridge widths on the stimuli that we used, and so we have a resolution of approximately 1–2 ridges on the fingerprint impressions.…”

“…The raw gaze data from the eyetracker were segmented into fixations and saccades. We have developed our own algorithm of eye fixation finding which uses eye motion to separate fixations (Busey et al., ; Parada et al., ). First, we perform a running median filter over the data, which takes the median of three consecutive points.…”

“…The eyetracking data were collected specifically for this project. We used hardware and software that was designed for portability to collect robust eye gaze data from forensic laboratories (Parada et al., ). The eyetracker uses one camera to record the position of the eye relative to the head, and a second camera to record the position of the head relative to the computer monitor that presents the fingerprints.…”

2018 Impression, Pattern and Trace Evidence Symposium

“…A variety of studies have evaluated the latent print examination process (e.g., Hicklin et al, 2011;Ulery, Hicklin, Buscaglia, & Roberts, 2011Ulery, Hicklin, Roberts, & Buscaglia, 2014a, 2014b, but relatively little research has addressed the fundamental basis of this visual task: how examiners use their eyes to accomplish these tasks and what visual information guides the examination process (Busey et al, 2011;Busey, Swofford, Vanderkolk, & Emerick, 2015;Busey, Yu, Wyatte, & Vanderkolk, 2013;Parada et al, 2015). This presentation will discuss the results of a study conducted to gain a greater understanding of how latent print examiners perform analysis and comparison tasks and of why examiners make different determinations.…”

The impact of fatigue on latent print examinations as revealed by behavioral and eye gaze testing

“…Eye gaze was recorded using custom eyetrackers constructed from NTSC cameras and processed using the ExpertEyes software package [8]. This provides for 30 Hz recording, which over a 20 min recording period provides approximately 36,000 gaze data points per participant per session.…”