The just noticeable deviation (jnd) of the position of light points in the grid structure of matrix signs was determined in a laboratory experiment. The stimuli, consisting of either lines (10 light points) or areas (10´10 light points), were presented on a colour VDU-screen. The variables tested were light point distance (2.75, 1.38 or 0.688 min of arc), spatial location (centre or edge of an area), direction of dislocation (cross-wise or length-wise in a line), colour (white, red, green, or blue), luminance ratio (1:560 or 1:10), and presentation time (1 or 5 s).
In een laboratoriumexperiment is onderzocht wat de maximum toelaatbare positie-afwijking mag zijn in de roosterstructuur van matrixborden. Op 100 m afstand en een gemiddelde lichtpuntafstand van 40 mm is dat 16 mm.