Viraphan Samadi creator Manukid Parnichkun Chairperson Pandey, P.C. Examination committee Afzulpurkar, Nitin V. Examination Committee text series technical report th Bangkok Asian Institute of Technology 1998 continuing eng 126 p. In this study a Laser Range Finder (LRF) was developed and a mathematical relation was estab lished between object distance and PSD (Position Sensitive Detector) voltage output. LRF is a single point optical triangulation instrument, which provides distance information quickly and easily without touching the object being measured. This kind of instrument is available in today's market. But it is limited to a short range (max. range about 400 millimeters). And the nonlinearity is inherent in this kind ofinstrument, resulting the accuracy and resolution are chang ing nonlinearly with the distance. As distance of the object being measured increase as the accu racy and resolution decrease. The LRF was developed to achieve longer operation range (one meter or more). To improve the instrument accuracy and resolution at long range, multi mode measurement scheme was introduced and implemented. This method simply magnifies the PSD output voltage at long range before feeding it to ADC (analog to digital converter). This method showed the ability to make the resolution finer considerably depending on the number of mode being used. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies Thesis (M.Eng.) - Asian Institute of Technology, 1998 Process control Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B13271 http://203.159.5.9/ait-thesis/detail.php?q=B13271 150799 20260818090649.0