A one-step intrinsic and extrinsic calibration method for laser line scanner operation in coordinate measuring machines

Abstract

A technique for intrinsic and extrinsic calibration of laser line scanners, also called laser triangulation sensors (LTSs), for integration in a coordinate measuring machine (CMM) is presented in this paper. Setting out from the modeling of a commercial LTS for use in a CMM and the algorithms implemented for image capture and processing, with the use of a gauge object, a one-step calibration procedure has been developed to obtain both intrinsic parameters—laser plane, CCD sensor and camera geometry—and extrinsic parameters which relate the LTS's reference system to the CMM's reference system, integrating both mathematical models. This method performs both calibrations in a single step, thus avoiding the digitalization of a reference sphere in order to obtain the extrinsic parameters, or optimization procedures subsequent to LTS calibration. The results obtained in accuracy and repeatability tests performed on gauge geometric primitives attest to the viability of this technique for the integration of LTSs in CMMs.

Summary of the Space Coordinate Measuring Technology Via Robots

“…At present, the robot can be composed of a variety of combinations as shown in Table 2 [5] . [6] ,Jorge Santolaria [7]- [9] robot + structured light sensor dental model, car model, etc. Wu D F [10]- [11] , Giovanna Sansoni [12]- [13] robot + Laser Scanner + camera mouse, kettle, etc.…”

Simulation of Laser Triangulation Sensors Scanning for Design and Evaluation Purposes

“…As shown in Fig. 4 [7], every 3D point (Xw,Yw,Zw) within the field of view has its correspondence in the 2D image plane (u,v). These u,v coordinates are obtained as the projection of the point into the image plane through the optical centre of the camera-optic combination.…”

“…The camera captures images of the diffuse reflection of a laser on the surface to be measured. Using the triangulation principle, the systems are able to provide the coordinates from the laser line image pixels, the calibration of the camera and the predetermined laser plane equations [7].…”

“…Therefore, these movements depend on the machine that performs the movement and on its degrees of freedom. Using an LTS, a CMM can perform at least 3 independent lineal movements [7], while robots usually have 6 angular degrees of freedom. An additional movement axis can be established if required [8].…”

Methodology for clamping load measurement of locking systems based on white light digitalization

“…Experimental measurement of the real clamping force after assembly allows to validate the theoretical calculations and to guarantee the proper design of the clip. To carry out such measurements and calculations different techniques can be used such as traditionally contact measurement methods [11], based on optical methods [12,13], or on tunneling effect [14]. This paper presents a new methodology of measurement of the clamping force to which a locking clip of a tensile luminary is subjected from the previous determination of its stiffness and the stretching it suffers under assembly and working conditions.…”