Table 2.
Power spectrum scaling exponents (α) for filtered and unfiltered human and artificial eye data determined by fitting a line to (left columns) the entire power spectrum, and (right columns) the first 100 Hz of the power spectrum
| Eye tracker | Fit to entire power spectrum | Fit to first 100 Hz | ||||||
|---|---|---|---|---|---|---|---|---|
| Filtered | Unfiltered | Filtered | Unfiltered | |||||
| Human | Artificial eye | Human | Artificial eye | Human | Artificial eye | Human | Artificial eye | |
| EyeLink | 2.281 | 2.328 | 0.544 | 0.081 | 1.307 | 0.466 | 1.179 | 0.219 |
| RED250 | 2.280 | 2.456 | 0.903 | –0.001 | 2.353 | 2.482 | 1.004 | 0.006 |
| RED-m | 0.886 | 1.364 | 0.330 | 0.210 | 0.886 | 1.364 | 0.330 | 0.210 |
| TX300 | – | – | 0.280 | 0.182 | – | – | 0.351 | 0.224 |
| X2-60 | – | – | 0.382 | 0.308 | – | – | 0.382 | 0.308 |
The power spectrum scaling exponents presented in this table were derived by averaging the exponents for horizontal and vertical gaze position data. Note that for the Tobii eye trackers, only unfiltered data were available. Note also that as the SMI RED-m and Tobii X2-60 had sampling frequencies below 200 Hz, fits to their entire spectrum were used for all entries in the table.