Eyelinktracker – cni wiki


After the subject has entered the scanner, go to the ‘Camera Setup’ screen of the Eyelink software interface. Usd euro chart This is the default screen after you turn the Eyelink computer on. Gold price history chart 100 years Check if you have a view of the illuminated eye (typically the left eye). Yahoo futures indices If you cannot see this eye, you may need to adjust the camera position.

Usa today To do this:

• Run a calibration script on your stimulus presentation computer. Rmb usd An example calibration script for Matlab Psychtoolbox, by Karen LaRocque, adapted from scripts by the Grill-Spector Lab is here.

• Select ‘Display Image’ on the Eyelink computer. 100 eur to usd Now the image of the subject’s eye will be displayed on the screen in the scanner. Dow jones futures exchange Using the left and right arrow keys on the Eyelink computer, you can toggle a large or small angle shot. Stock connect china When initially searching for the eye, it’s helpful to use the large angle shot.

Note that the subject’s eye may also be occluded by the mirrors or coil. Today’s futures market Often, when the dorsal part of a subject’s head is flush with the 32 channel coil, the camera will not have view of her eyes. Cad usd exchange rate To rectify this, ask the subject to scoot out of the scanner, 1 cm at a time, until you can see her eyes.

• Adjust the pupil threshold, using the arrows in the top left corner of the Camera Setup screen. Rub usd converter The threshold should be set such that the subject’s pupils are optimally labeled in dark blue, with minimal labeling in the areas immediately outside the eye. Litecoin charts When a pupil is detected, you will see a message indicating “PUPIL OK” in green.

• Adjust the CR (corneal reflection) threshold, using the arrows in the top left corner of the Camera Setup screen. Usd jpy chart When corneal reflection is detected, you will see a message indicating “CR OK” The threshold should be set such that “CR OK” is displayed when subjects look at each region of the display screen.

• Now Eyelink will complete the calibration process. Market futures yahoo Dots will appear at various points of the screen, and the subject is required to fixate on each presented dot.

• After calibration is complete press “accept.” Then, validate the calibration by pressing “Validate.” Another run of dot presentation will be conducted, and measurements will be computed indicating the error between estimated points of fixation for the calibration and validation runs. Usd to zar exchange rate history Based on the computed error, Eyelink will label the validation as “good” “fair” or “poor.” If you are satisfied with the precision of your measurement, click “accept.” Otherwise, you can repeat the full calibration and validation process.

Now you are ready to run your study. What is the futures market You can update your presentation scripts to include code that communicates with Eyelink, in order to label trials and download data from the Eyelink computer. Binary search tree program in c For more info about the Eyelink system, you can view the Eyelink manual. Gender pregnancy Technical Details

We found that the standard IR light source from SR Research did not adequately focus the light onto the subject’s eye, so we built a small MR-safe IR source using a single high-power IR LED epoxied to a non-metallic heat sink. Exchange rate usd to inr The illuminator is mounted on the head coil using a loc-line stalk and can be positioned to nicely illuminate the target eye. Stock market trading hours new years eve It’s powered from the same 5v source that powered the original SR illustrator (and that powers the camera) via a simple circuit based around a 1.8v linear regulator (it turns out that 1.8v drives this LED with just the right amount of current). Eur usd news today The circuit was just the standard “typical application” circuit for a fixed voltage regulator, with a 100uF capacitor on the input and one on the output. Rate of exchange usd to zar We did have an issue with the RF pulses from the scanner causing some flicker in the illuminator, so we added a pair of 1000uF capacitors in parallel with the 100uF caps, and that minimized the flicker to a level that didn’t interfere with eye tracking.

Here are some pictures of the very crude, “dead-bug” style circuit. Decimal division calculator Note that we neatly tucked it into the original eyelink IR illuminator case and we used an old cat-5 cable to connect the regulator with with IR source. Futures market size The IR source was mounted to the plastic heat sink using thermal epoxy.