Comparison of n x n grille CTF measurement for VESA standard and large sample aperture methods

摘要

An alternative method for measuring the contrast transfer function (CTF) of a pixilated display is proposed that reduces the amount of time required to perform a high sample rate-small aperture luminance scan as outlined in the Video Electronics Standards Association (VESA) standard for measuring the contrast of an n X n grille. The alternative method proposed by the Night Vision Electronic Sensors Directorate (NVESD) Displays group utilizes round sampling apertures and large step sizes to achieve comparable results to the VESA standard method. Theoretical predictions and experimental measurements demonstrated the equivalency between the proposed large aperture method and the VESA standard method with less than 8% maximum variation and an average of 2.4% variation between the two methods over two different input contrasts and 4 different grille frequencies. Experimental results also show a reduction in time to perform the profile scan by as much as 15:1 for the NVESD proposed test method over the VESA standard method.