Hi Chris,
It would be super useful if in a future mworks release, we could get an addon to the calibration window that allows the manual increase of a single offset value in visual degree angles. Currently the calibration window allows a manual input of the calibration variables, but the units seem to be in arbitrary values, and anytime I’ve tried changing one and clicking update it ends up in throwing the entire calibration off (perhaps i’m doing it wrong :).
The reason is, if we have a particularly fidgety monkey that ends up moving a bit halfway through a session, where the eye is up and to the left, it would be useful to just manually move the eye back to 0,0 without having to rerun the entire calibration scheme - which can sometimes make post-processing of the data file more troublesome. this could also be accomplished with a ‘zeroing’ button that we could push when we ‘know’ the monkey is looking at fixation.
Just a thought!
Travis
Hi Travis,
It would be super useful if in a future mworks release, we could get an addon to the calibration window that allows the manual increase of a single offset value in visual degree angles. Currently the calibration window allows a manual input of the calibration variables, but the units seem to be in arbitrary values, and anytime I’ve tried changing one and clicking update it ends up in throwing the entire calibration off (perhaps i’m doing it wrong :).
The offsets already are in visual angle degrees. I think the problem you’re having results from the eye calibrator window resetting the “hidden” calibration parameters to zero when your press “Update”.
Specifically, if you’re using a linear eye calibrator, then the calibrator fits the equations
h_cal = offset_h + gain_hh * h_raw + gain_hv * v_raw
v_cal = offset_v + gain_vh * h_raw + gain_vv * v_raw
The eye calibrator window exposes offset_h, offset_v, gain_hh, and gain_vv, but it doesn’t let you set gain_hv or gain_vh. Furthermore, when you change one or more of the exposed parameters and click “Update”, gain_hv and gain_vh are set to zero. I suspect your calibration is being thrown off because these terms are significant.
Fortunately, you aren’t the first to have this problem, and there’s already a fix for it. In MWorks 0.12, the calibrator window has an option to “Preserve hidden parameters on update”. If you enable this, then gain_hv/gain_vh will be left unchanged on update. This should let you adjust the offsets without changing anything else about the calibration. I have no idea why the eye calibrator window hasn’t always worked this way (if you really want to clear the parameters, you can just click “Reset”), but at least it now gives you the option of working as you’d expect.
Cheers,
Chris