User manual

2.3.4 Calibrate Screen

28 EyeLink 1000 Host Application

2.3.4.1 Calibrate Screen Purpose

Calibration is used to collect fixation samples from known target points in order

to map raw eye data to either gaze position or HREF data. Targets are serially

presented by the Display PC. The participant fixates each while samples are

collected and feedback graphics are presented on the Host PC display. The

calibration is automatically checked when finished, and diagnostics are

provided. Calibration should be performed after camera setup and before

Validation. Validation provides the experimenter with information about

calibration accuracy.

The zoomed and global views of the camera image, along with pupil and CR

threshold values, are displayed at the bottom left of the screen. The eye to be

calibrated as well as the calibration type (as defined in the Set Options screen

or via the EyeLink API) is indicated beside the camera images at the bottom of

the screen. The calibration status and current calibration target being

presented are indicated on the bottom right of the screen.

To perform a calibration, have the participant look at the first fixation point and

select the ’Accept Fixation‘ button, ENTER or the Spacebar, to start the

calibration. If ‘Auto Trigger’ is disabled (‘Force Manual Accept’ from the Set

Options screen is enabled), repeat this action after each target fixation.

Performing one of these actions quickly, twice in succession, can switch from an

automatic calibration to forcing a manual calibration at any point into the

calibration sequence. This can be useful for subjects showing difficulty fixating

targets or who inappropriately anticipate new target positions.

Figure 2-5 Calibrate Screen