Guidelines to perform Triangle Orientation Discrimination (TOD) measurements are given in the present paper. The optimal range of test pattern sizes and contrasts are specified, as well as the required number of presentations for a threshold estimate. Special attention is paid to the statistical analysis. A standard frequency-of-serving curve is fitted to the observer data in order to obtain 75%- correct thresholds. A (chi) 2-statistic provides an objective criterion for acceptance or rejection of the threshold estimates. Finally, a complete TOD curve is obtained by fitting a weighted least-square polynomial through the 75%-correct thresholds. Further, a simple Go- NoGo screening procedure with objective pass/fail criteria, based on the TOD methodology, is proposed. With the TOD methodology, accurate sensor performance measured and Go- NoGo testing have become very easy to carry out. Therefore, the investment in a thoroughly design measurement setup will apply itself back easily.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.