Abstract
Laser stripe center extraction is a key step for the profile measurement of line structured light sensors (LSLS). To accurately obtain the center coordinates at sub-pixel level, an improved gray-gravity method (IGGM) was proposed. Firstly, the center points of the stripe were computed using the gray-gravity method (GGM) for all columns of the image. By fitting these points using the moving least squares algorithm, the tangential vector, the normal vector and the radius of curvature can be robustly obtained. One rectangular region could be defined around each of the center points. Its two sides that are parallel to the tangential vector could alter their lengths according to the radius of the curvature. After that, the coordinate for each center point was recalculated within the rectangular region and in the direction of the normal vector. The center uncertainty was also analyzed based on the Monte Carlo method. The obtained experimental results indicate that the IGGM is suitable for both the smooth stripes and the ones with sharp corners. The high accuracy center points can be obtained at a relatively low computation cost. The measured results of the stairs and the screw surface further demonstrate the effectiveness of the method.
Highlights
As a non-contact measuring apparatus, the line structured light sensor (LSLS) can effectively obtain a huge amount of surface data from objects with the advantages of simple construction, low cost and moderate precision
Based on the relationship established between the width of the rectangular region and the radius of curvature of the stripe, the width of the rectangular region would automatically change with the radius of curvature within a reasonable range
From the Monte Carlo simulation, it can be seen that the uncertainty values for the center extraction are lower than the gray-gravity method (GGM) and the Gaussian fitting (GF) under different noise amplitudes
Summary
As a non-contact measuring apparatus, the line structured light sensor (LSLS) can effectively obtain a huge amount of surface data from objects with the advantages of simple construction, low cost and moderate precision. It has been widely used for profile measurement [1], reverse engineering [2], welding inspection [3], visual tracking [4], etc. The simplest pixel level center extraction method is the extreme value method. It is achieved just by choosing the pixel with the maximum gray value as the center of the specific transverse profile
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
