Home › Forums › Software Development › Specifications regarding analytical use › Reply To: Specifications regarding analytical use

Hi @rasa, good to hear that you managed to find a tool that will help you determine fixations based on the raw gaze data. Would be useful if you could share the source please?

But I do not understand how is it that researchers use degree/second to calculate it ? I mean the value that is given here is shown in pixels. So how do I convert it to degrees/second to calculate saccade velocity ?

So, this is similar to what was discussed in a previous post @ https://developer.tobii.com/community/forums/topic/accuracy-in-tobii-eye-x/

where one would first calculate the linear distance between two set of pixels co-ordinates using pythagoras theorem.. what is missing from the data above is the distance between the screen and the user. Once you have both the linear distance travelled between two fixations and the distance between screen and user you would determine the angle travelled as = tan-1 (linear distance between fixations / distance between screen and user) and so therefore the sacaddic velocity would be this distance divided by the time elapsed between each fixation.

Hopefully this is clear, let me know.