Converts Visual Angle to Pixel & Reverse
A pretty simple set of functions. Require the psychtoolbox.
Simply run:
visual_angle2pixel(visual_angle, screen_diagonal, distance, screen_no)
The function will take your screen number and use psychtoolbox to find the dimensions of that screen.
It will then use the physical dimensions you provide (screen_diagonal and distance) to work out the stimulus size in pixels.
You can do the same in reverse, although that's not as useful :)