Screen coordinates

For the Virtalis system, July 2008.
Currently, we have the Virtalis system in rear-projection mode, i.e. with the text etc the right way round as viewed by the experimental observer. This means that the text is backwards as viewed from the stimulus control computer behind the screens. This is convenient because in our new lab, the signals to each projector now passes through DVI splitter boxes which mirror the signal to two LCD monitors in front of the experimenter. This means the experimenter doesn’t need to turn round to look at the image on the projector. Having the text the right way round for the observer means that the observer can interact with the control computer using a wireless keyboard and mouse. This is handy if you want to make small changes to the Matlab code and then set the experiment running again. We are displaying the images in Psychophysics Toolbox stereomode 4 (split-screen/dual-display)