Papers by Keyword: 3D Measurement

Abstract: This paper integrated a laser triangulation probe with a two-dimensional image measurement system to measure the height of an object using the auto-focusing method. In the laser triangulation probe, the laser diode was used as the light source and one-dimensional position sensitive detector was adopted to receive the position of the laser spots to detect the height. The laser triangulation probe was used for small height measurement and the auto-focusing method was used for large height measurement. Two standard gauges with thicknesses of 8mm and 8.5mm were used to verify our proposed method. With height difference of 500μm, the experiment results showed the measuring error was within ±3μm and standard deviation was about 0.1μm.

Abstract: Here we propose a new approach for measuring the environment for the mobile robot. Without using any old framework of sensors; we utilized the latest vision system -- the spherical camera system - which consists of several cameras around a certain geometric surface. Equipped with a lift device, the spherical camera system can measure the environment around itself. We present some results of simulated and real experiments showing the validity of our method. Our approach is acceptable and exciting, and will be applied in the mobile robot’s application in the future.

Abstract: Over the last few years hot stamping for its high strength, lightweight characteristics has developed at an alarming rate, At the same time the measurement process a higher demand. Compared with the traditional three-dimensional coordinate measurement, Hand-held Blue structured Light 3D measurement technology for its fast, high precision, good flexibility, etc., has become the best choice of high-strength steel stamping in non-contact 3D measurement and accuracy detection. This paper developed a set of holding blue light 3D measurement system. The system project blue structured pattern to the surface of the object, and captured by two high-speed cameras synchronized. Then using the grabbed pictures reconstruct 3D topography of the object. Blue light projection technology can eliminate the use of influence of different surface reflectance measurement accuracy, So that a single measurement accuracy of 0.02mm, overall measurement accuracy of 0.05mm / m, Single measurement time is less than 0.12 seconds. This measuring system can be widely used in the rapid detection of various types of three-dimensional measurement and precision casting.

Abstract: The 3D Shape Measuring Technology for physical objects has wide application in fields covering automatic detection, physical object profile modelling, automatic production, computer aided design/manufacturing and quality control, etc. Through the matching relations of several feature points between the partial 3D scanning point cloud data and the space frame, the transformation relations between different coordinate systems can be inferred. As for the inferring of the transformation parameters R and T, the SVD matrix decomposition algorithm has been used to acquire a better precision solution. According to the transformation relation, after registering the partial 3D scanning point cloud data and the space frame, through splicing the partial scanning point cloud data and the space frame data, the detection across the whole field on large-area objects can be realized, which will effectively increase the precision of three-dimensional measuring of large-area objects.

Abstract: Nowadays there is a huge interest in new and improved three-dimensional techniques of surface finishing degree measuring and behaviour investigation. Several fields of application are mainly dependent of advances in surface metrology, as for instance aerospace and rail transport, telecommunications or micro-technology. All 3D measuring tools must be designed starting from a bi-dimensional basis and keeping a clear knowledge of their operating principle. This is then the key that defines the borders of this works path. Looking at the finishing degree of three differently obtained surfaces, preliminary comparison of results in two and three dimensions will be finally presented. All constraints defined by this problems conditions must be taken in consideration once the results are analysed.

Abstract: Adopting high-speed line scan industrial camera, through window function of the software to capture interested areas scanning by linear structured light, through image processing algorithms and splicing technique to extract 3D feature information of the detected object surface, combined with the camera calibration technology, calculated the three-dimensional coordinates of the detected object, and real-time displayed intuitive pseudo color map, monitored picture signal and weeded out unqualified products. Compared with similar systems at home and abroad, the system are real-time pseudo color graphics display, open system and lower cost.

Abstract: In SMT solder paste deposit 3D measurement based on PMP, conventional phase unwrapping method suffered from shadow, noise and holes. Considering practical engineering condition, phase unwrapping method can be improved using 2D image information: basic principle method was applied to smooth area, quality-guided unwrapping and least-square method were taken in shadow or break area for phase unwrapping respectively. Experimental results show that desired phases can be correctly and quickly unwrapped in proposed method.

Abstract: According to the principle of speckle photography, CCD(Charge-Coupled Device) as a recorder, and EALCD(Electrically Addressed Liquid Crystal Display) as a read-out element, which makes the speckle photography to digital. Recording light path of the subjective and the objective speckle and observation light path of full-field analysis and point-by-point analysis for fringe reconstruction have been respectively researched. At the same time, measuring by speckle photography, the fringes in the interometry pattern must be carefully analyzed. Since the speckle noise can greatly infect the signals. Thus to de-noising the speckle fringe by a suitable filter before processing is expected. The mathod of digital filter enhancement, smooth denoising be used to reduce the influence of the high noise and the inhomogeneous grey of the speckle interferogram. Finally the thinning fringe is acquired, the fringe spacing is extracted accurately, the three-dimensional measurement of a deformed object is realized with mathematical morphological thinning algorithm.

Abstract: When the cylindrical NdFeB magnet was magnetized along the axle wire, the magnetic field around the magnet was symmetric about the axle wire. The output voltage of Hall sensor was proportional to magnetic induction induced by itself. Around the magnet, the magnetic induction component along the axle wire could be measured by Hall sensor. The contour line and contour surface of magnetic induction could be plotted by MATLAB. A sensor array was composed of three Hall sensors in triangular distribution, and 3D Cartesian Coordinate System was established. 3D coordinate of magnet can be measured with this sensor array based on contour surface. Underground soil deformation will change the relative position of sensor array and magnet. The size of geotechnical displacement can be calculated after getting the new 3D coordinate of magnet. Along with dual-axis magnetic sensor based on MR effect, the orientation of geotechnical displacement can be measured, and so able to measure the underground displacement.

Abstract: The aim of our research is to realize a high-sensitivity three-dimensional (3-D) shape measurement of target with an optical microscope. On the conventional method – shape from focus, it’s to regulate focal length of microscope to obtain 3-D shape information of the specimen. However, the method is used the vertical stratification method to obtain 3-D shape information of total surface of target, and the variable focal length of zoom lens is limited therefore the measurement accurate is confined on the vertical direction. In order to solve these problems, we propose a high-sensitivity 3-D shape measurement method based on microscope and laser projection. The method is based on the slit pattern projection technique and 3-D image processing technique. The proposal method can be used for medicine, pharmacy, life science, and material science.