Laser image spot processing for sea oil film thickness measurement

The method of extracting the center coordinate of the light spot using the improved Gaussian fitting is presented to measure the thickness of oil film on water surface with differential laser trigonometry. The image of the light spot from the upper and lower surfaces of the oil film under measurement is extracted by the entropic threshold, and the center coordinate of the light spot is obtained by Gaussian fitting of the ascending edge and descending edge data of the light spot image extracted. Experimental measurement is carried out to verify the performance of the method. The range of the measurement is 0.1–10?mm and the maximum deviation between the nominal value and the measured value is less than?±23?μm for block gauges. The research results show that the algorithm presented in this paper is successful and feasible.