Daq

ISCAN^® infrared eye tracking data acquisition system

usage: Daq3_55b

Daq is a commercial program from ISCAN^® that records direction of gaze and event codes during an experiment. Configuring Daq to work with fastshft requires the following steps:

• Press ALT-C to activate the Config menu, then choose GENERAL. Set Rec Trig (X) to SERIAL. (Daq will also accept manual triggers from the keyboard even when it's in serial trigger mode.) The other options should be left at their defaults:

  Rec Trig	SERIAL
  Video	NTSC
  Intrlace	INTERLACED
  Horz Res	512
  IRQ Level	IRQ5
  IRQ Src	RK-4X6

  Press ESC when you're finished setting these parameters.

• Press ALT-C again, and choose the AUX SERIAL INPUT configuration panel. Set INput Status to ON, Input Port to COM2, and Baud rate to 19200. Then press ESC.

• Press O repeatedly until the RECORDING SELECT CONTROL appears in the lower left panel of the display. Now Select each recording channel and choose one of the Parameters to be recorded on it. POR H1, POR V1, and SerIn0 suffice for most applications; the default set of parameters also includes Pupil D1, P-CR H1, and P-CR V1.

• Position the infrared LED array to illuminate the eye as nearly frontally as possible.

• Angle the mirror so that the projection screen is visible to the subject and the subject's eye is visible to the camera.

• Find the eye with the camera, and focus on it.

• Press T to turn on the thresholded display of the eye. Press F7 and F8, respectively, to alter the thresholds for detection of pupil image and corneal reflection. (Make sure that the Pupil X-Hair and C.R. X-Hair options are on so that you can see the effects of these threshold manipulations on the computation of the pupil and corneal centroids.)

  Geometric gating of the eye signal may be of use in excluding regions incorrectly identified by the thresholding routine: press ALT-C, then choose EYE TRACKER #1 AUX. Set IMAGE GATE ON and use the frame overlaid on the display as a guide for mofifying the LEFT, RIGHT, TOP, and BOTTOM gate values. Typical values for the other parameters are as follows:

  Max pupil	5000
  Min pupil	30
  Max CRefl	2000
  Min CRefl	5

  Press ESC when you're finished setting these parameters.

• Press O repeatedly till the POR CALIBRATOR #1 configuration panel is displayed. Press M to turn on the moving display of gaze position. On the stimulus-delivery machine, start MEL, fastshft, or other stimulus-delivery software that displays calibration points. Press R to reset the calibrator and L to begin calibrating. During calibration, use S to select a point at the centre or any of the corners of the display, and ENTER to sample the gaze data while the subject is looking at that point. When finished calibrating, press R to reset. If the calibration was successful, an asterisk will appear to the right of the POR Output label, indicating that calibrated point-of-regard data are available. Press P to display the data. You may have to iterate through several steps of re-calibration and display before achieving a display that seems reasonable.

• When a good calibration has been achieved, the system is ready to record data. Press O till the EYE DATA RECORDING CONTROL panel is displayed. Make sure the Pts/Run Limit field is set to something large (e.g. 36000, which will allow a ten-minute continuous recording). Recording can be triggered from the stimulus-delivery machine via the serial port, or started manually by pressing the R key. Recording can be stopped via the serial port, or manually by pressing the Q key. IN ORDER TO RECORD, THE DISPLAY MUST BE IN MOVE MODE.

• At the end of the recording session (potentially after multiple starts and stops), press M to halt the moving display, and ALT-F to activate the File menu. Then save the current recording as a file. After saving, press Z to zero the recording and M to start the display moving again. This procedure can be repeated so as to generate many separate recordings during a single session.

• When finished with all recordings, exit the program from the File menu.