A new and general approach to signal denoising and eye movement classification based on segmented linear regression

• Published in: Scientific reports Vol. 7; no. 1; pp. 17726 - 13
• Main Authors: Pekkanen, Jami, Lappi, Otto
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.12.2017; Nature Publishing Group
• Subjects: 631/378/2613; 639/705/1041; 639/705/794; Classification; Data processing; Eye; Eye Movement Measurements - classification; Eye movements; Eye Movements - physiology; Field tests; Fixation, Ocular; Humanities and Social Sciences; Humans; Laboratories; Linear Models; multidisciplinary; Noise; Oscillations; Pursuit, Smooth - physiology; Saccades; Saccadic eye movements; Science; Science (multidisciplinary); Segmentation; Signal-To-Noise Ratio; Software
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-17983-x

We introduce a conceptually novel method for eye-movement signal analysis. The method is general in that it does not place severe restrictions on sampling frequency, measurement noise or subject behavior. Event identification is based on segmentation that simultaneously denoises the signal and determines event boundaries. The full gaze position time-series is segmented into an approximately optimal piecewise linear function in O ( n ) time. Gaze feature parameters for classification into fixations, saccades, smooth pursuits and post-saccadic oscillations are derived from human labeling in a data-driven manner. The range of oculomotor events identified and the powerful denoising performance make the method useable for both low-noise controlled laboratory settings and high-noise complex field experiments. This is desirable for harmonizing the gaze behavior (in the wild) and oculomotor event identification (in the laboratory) approaches to eye movement behavior. Denoising and classification performance are assessed using multiple datasets. Full open source implementation is included.