prosdk-addons-matlab - Calibration validation

What is it

Add-ons for the Tobii Pro SDK.

The Tobii Pro SDK is available at: https://www.tobiipro.com/product-listing/tobii-pro-sdk/
Documentation to the API: http://developer.tobiipro.com/matlab.html

Calibration Validation

• To use this feature it is necessary to have the SDK in the Matlab's path.
• Next just add to the Matlab's path the downloaded or cloned folder of the this repository.

Do not hesitate to contribute to this project and create issues if you find something that might be wrong or could be improved.

Example

Before starting a calibration validation, it is needed some setup with the desired tracker.

Tobii = EyeTrackingOperations();

eyetracker_address = 'Replace the address of the desired tracker';

eyetracker = Tobii.get_eyetracker(eyetracker_address);

Now it is possible to create a calibration validation object with the eye tracker object previously created. More information about this class and its methods can be found in the ScreenBasedCalibrationValidation definition.

sample_count = 30;
time_out_ms = 1000;

calib = ScreenBasedCalibrationValidation(eyetracker, sample_count, time_out_ms);

The next step is to enter validation mode. Note that this action will lead to the tracker to start collecting gaze data.

calib.enter_validation_mode();

List the points that are to be used during the validation.

points_to_collect = [[0.1,0.1];[0.1,0.9];[0.5,0.5];[0.9,0.1];[0.9,0.9]];

When collecting data a point should be presented on the screen in the appropriate position.

for i=1:size(points_to_collect,1)
    calib.collect_data(points_to_collect(i,:));
end

Next just call the compute method to obtain the calibration validation result object.

calibration_result = calib.compute();

Now the calibration result should be available for inspection. This can be done by accessing each individual property:

calibration_result.Points
calibration_result.AverageAccuracyLeftEye
calibration_result.AveragePrecisionLeftEye
calibration_result.AveragePrecisionRMSLeftEye
calibration_result.AverageAccuracyRightEye
calibration_result.AveragePrecisionRightEye
calibration_result.AveragePrecisionRMSRightEye

More information about the calibration validation result can be found in the CalibrationValidationResult definition.

If the result is satisfactory then the only thing left to do is to leave validation mode. This action will clear all the data collected in the current validation session and will stop the gaze data collection from the tracker.

calib.leave_validation_mode()