Screen Calibration Utility

The Screen Calibration utility is a tool for measuring physical screen dimensions and viewing distance, which is essential for experiments requiring precise stimulus sizing in visual angle or physical units. Participants can calibrate using various reference objects: a ruler (cm or inches), a credit card (85.6mm x 54mm), US Letter paper (8.5" x 11"), or A4 paper (210mm x 297mm). The tool allows interactive adjustment of on-screen objects to match the physical reference, calculating pixels per millimeter and pixels per inch. Optionally, viewing distance can be estimated using angular size matching (holding a credit card at arm's length and matching its apparent size on screen). The calibration data is saved and includes screen dimensions, resolution, and viewing distance. This utility should be run before visual perception experiments to ensure accurate stimulus presentation and enable conversion between pixels and visual angles.
