The Bessel light triangulation system has the advantages of long measurement range, high accuracy and resolution over
the traditional laser triangulation system. Unfortunately the measurement accuracy is degraded due to various noises in
practical application. In order to improve the measurement accuracy, a novel effective location method for the center
spot of the Bessel light is presented in this paper through the improved spin filtering and gray scale bilinear interpolation.
In this method, the stripe orientation is accurately estimated by using surface fitting for gray scale, determine the gray
scale contoured window based on a map of the stripe orientation, and apply grey relational analysis so as to remove the
interference noises. Then the center spot region, roughly obtained by adaptive threshold method, is implemented bilinear
interpolation for gray scale to specify the accurate location of the center spot, which is extracted with the centroid
method for gray scale. Through the sample and simulation analysis, the proposed method is insensitive to the
imperfection of the Bessel light intensity distribution and has better performance of anti-noise. In addition, the result of
locating the center spot is more reliable with the accuracy of sub-pixels.