The Measurement System Of Laser Triangulation Integrated With CMM

With the development of the science technique, the measurement technique of objects' three-dimension figure has developed rapidly. Three-dimension geometry sculpting technique has been applied to design of mould, scheme assessment, automatic manufacture and maintenance etc. It needs in science investigation and industry production to convert objects to 3D digital model on computer quickly sometimes. Recently there are lots of objects' three dimension figure measurements have been excogitated, the theory of laser triangulation is one of the optics measurements applied broadly. And the most widely used contact measuring device is CMM.Laser triangulation method has many advantages, such as non-contact, not easy to damage the surface, wide adaptability of materials, simple structure, strong anti-interference ability, measure fast etc. The object must be contacted by contact CMM, so the surface will be damaged, and this measurement can't be used for the flexible object. The measure speed of CMM is slow and more steps to operate.The measurement system in this thesis is the measurement system of laser triangulation integrated with CMM. Through CMM's precise mobile machine to scan the surface to obtain three-dimensional surface information of objects, the acquisition of image through the Matlab image processing to reconstruct surfaces in any directions.The characteristics and innovations of this thesis are listed as follows:1. After study of laser triangulation and CMM, design the measurement system of laser triangulation integrated with CMM. This system improve the efficiency of the measurement; expand the original measured object and range; retain the original characteristics anti-jamming, high precision and fast measurement etc; objects can be measured from multi-angle for clamping once. 2. The measurement interface is designed through Visual Basic software development tools, by calling functions of the camera and CMM's PC-DMIS measurement software to achieve the probe's movement and the image acquisition automatically to improve the efficiency of the measurement.3. A novel corresponding calibration method is studied in this thesis. The relationship between world coordinates and the corresponding image coordinates is modeled as a three order polynomial. The geometrical relation of the system doesn't need to educe and the system has taken into account the influence of lens aberration. The displacement in X, Y, Z directions can be calibrated at the same time, which makes up the lack in calibrating only the deep direction (Z direction) in many previous methods.The primary contents in this thesis are listed as follows:1. The background and purport of this thesis are expatiated. Contact measurement and non-contact measurement, especially the laser triangulation and CMM, and their development are also analyzed and compared.2. After the study of laser triangulation and CMM, design the measurement system of laser triangulation integrated with CMM.3. Using Visual Basic software development tools for the design of measurement interface, and obtain the image information through this measurement interface.4. Some laser optical center coordinates obtained methods are analyzed and compared, and Matlab is used as image processing tool for image processing.5. A novel corresponding calibration method is studied in this thesis, and the system is calibrated through this method.6. Experiment through the measurement system, and reconstruction. The object's information are obtained through the system, then images are processed through Matlab to fit the surface of the object.