Synchronization device for Tobii Pro TX300
The StimTracker enables you to reliably and accurately synchronize on-screen stimuli and eye tracking data from our 300 Hz eye tracking system down to a single millisecond.
The versatile StimTracker is able to connect to several leading EEG and biometric data collection systems, as well as a PC parallel port. These multi-purpose connections enable the system to StimTracker also provides a versatile solution to screen-based stimuli and eye tracking with physiological data.
Synchronizing on-screen stimuli and eye tracking data
StimTracker provides a reliable and accurate solution to synchronize screen-based stimuli (e.g. images shown in Tobii Pro Studio and eye tracking data from Pro TX300 down to an average timing accuracy of 1.7 milliseconds. This exceptional timing accuracy benefits studies that require a high temporal resolution, such as reaction time tests and subliminal single-frame stimuli tests.
Independent of delays in operating systems, graphic cards, or pixel refresh algorithms, pixel changes on the screen are detected by a light sensor and then sent by the StimTracker to the Pro TX300 as event markers. Stimuli changes can then be accessed by users of Pro Studio 3.1 or higher directly in their eye tracking data, or they can be exported to other analysis programs. In addition, any other stimuli presentation or eye tracking recording software that works with our eye tracker through the Tobii Pro Analytics SDK can be used.
Synchronizing on-screen stimuli and eye tracking data with other physiological data
The StimTracker also provides a versatile solution for synchronizing on-screen stimuli and eye tracking information with other physiological data. This system connects to a range of external EEG products and other biometric data collection systems. The stimuli and EEG data can be synchronized with an estimated timing accuracy of approximately 1/EEG frame rate (1 milliseconds for 1 kHz EEG system). The accuracy of the synchronization between screen stimuli and eye tracking data depends on the sampling rate of the Pro TX300 (3.33 milliseconds for 300 Hz).
The exceptional timing accuracy enables researchers to know exactly where someone looks when certain effects in the human body occur. Saccades, larger micro saccades, and blinks can be detected and, from that information, artifacts in the EEG or other data can be corrected.
Researchers can more easily compare the synchronization signals of eye tracking data and EEG or other biometric data sync signals in post-analyses.
The StimTracker is compatible with, and equipped to connect to, the following EEG and other biometric data collection systems (through Cedrus-manufactured adapter boards):
The StimTracker is also able to connect to a PC parallel port, and, thereby, to PC-based recording systems, such as those manufactured by MindWare Technologies. For more synchronization options, visit the Cedrus website.
The numerous device connection possibilities allow researchers to synchronize eye tracking data with a broad spectrum of other data types, including EEG, NIRS, skin conductance, motion detection, respiration rate, heart rate, light, and sound.
Dedicated software tool
Once a Pro TX300 recording is complete in Pro Studio using the StimTracker, the Biometric Software Suite lets you comfortably synchronize both data streams while offering additional filtering options, including the Butterworth Filter, Segmentation, Fourier Transformation, and RBridge. This system also allows you to re-import biometric video into Pro Studio for a fast qualitative evaluation.
Close partnerships and integration with third-party products such as StimTracker (Cedrus), Biometric Software Suite (Dr Hornecker) and E-Prime (PST) make Tobii Pro eye trackers compatible with a large variety of biometric sensors.
For an overview of current eye tracking and biometric data sync options, please refer to our separate compatibility table.
A light sensor solution
By using an analog light sensor, the StimTracker for Tobii Pro TX300 provides a fast, robust, and reliable solution. The system is free from any software or timing errors that might occur due to delays in operating systems, graphic cards, or pixel-refresh algorithms. Windows and Linux are not real-time operating systems which can make it difficult to ensure that a picture was shown at an exact time. The StimTracker's light sensor solution overcomes this issue.
How does it work?
When a new stimulus is shown, the Cedrus Light Sensor detects a change and generates a TTL binary voltage signal (0 and 5 V). The signal is then transmitted via the StimTracker unit to the Pro TX300 and the other biometric data collection system. The eye tracker receives the signal, creates an event, and packages it with the next gaze data package. The StimTracker event is time stamped with the same time value as the gaze point. The eye tracker sends the data to Pro Studio and the StimTracker data (EventMarker) is integrated in the eye tracking recording. Events can then be used to post-synchronize the eye tracking information with the other biometric system data.