Papers by Keyword: Scanner

Abstract: The paper presents the bases of a methodology for obtaining a 3D solid model by three-dimensional scanning. The three-dimensional scanning has been available for more than 15 years; and yet, some people have heard of it but a few are familiar with the applications of this technology. 3D scanning is also known as 3D digitization, its name coming from the fact that it is a process that employs a contact or non-contact digitizing feeler in order to capture the form of objects and recreate them as 3D graphic representations in a virtual work space through a very dense network of points (xyz). By means of certain specialized programmes, we can obtain not only the tool’s geometric parameters that can be compared with the obligatory parameters, but also a direct evaluation of the geometric deviations from ideal values.

Abstract: The article describes sensory subsystem required for proper operation of a special segment wheel designed for smooth driving both on a flat surface and on stairs. This subsystem contains two 2D laser scanners Hokuyo oriented towards stairs that provide point clouds for further processing. The main part of the article deals with the algorithm for detection of stair features (surfaces of stair treads and risers) in the data, including initial noise filtering. The conclusion provides practical testing performed on few real staircases and evaluation of the results.

Abstract: A MEMS(Micro-Electro-Mechanical Systems) scanning mirror with vertical comb actuator was designed, modeled, fabricated and tested, which can be widely applied in scanning micromirrors, optical switches, and variable capacitors. Purposive latching has been successfully applied to the batch fabrication of vertical comb actuators made of silicon on insulator (SOI). The manufacturing process is introduced, and a novel design of latching structure and mechanical spring is also presented. The latching of microstructures is enabled in a controlled manner and significantly reduces the distance between the combs, reducing the driving voltage. The prototype microactuators operate at the driving voltage of 28 V_dc with 9.6 optical angle. A reliability test on an unpackaged actuator with more than 100 million cycles of operation showed extremely small variation in the scanning angle and the driving voltage, showing no sign of degradation in the induced latching interface or the microstructures.

Abstract: Scanner is the indispensable image acquisition equipment in the prepress system, high quality ICC profile is significant to reflect the color expression of scanner, and the character of ICC profile is influenced in a great extent by the color input target. The subject is to set up the ICC profile by scanning and data processing Kodak IT8.7/2, Goldencolor GCT 3.0 and GretagMacbeth ColorChecker SG, get the influence of each color input target to the scanner color characteristic through the accuracy analysis and color gamut comparison. Research shows that three kinds of color target has its own advantage, Kodak IT8.7/2 has big color gamut, high accuracy, and better reappearance ability, meets the needs of the everyday users; GretagMacbeth ColorChecker SG is good to the reappearance of high saturate manuscript, and its precision is high, applying to recreate natural landscape; Glodencolor GCT 3.0 is of high precision and larger color gamut, but its expression ability is not good enough in the section of high saturation red and magenta, it can produce high quality scanner ICC profile also. Consequently, it should be taken into consideration of the manuscript, color gamut, accuracy and cost-effective factors comprehensively when choosing scanner color target, eventually you get a satisfactory scanning result.

Abstract: We propose control techniques to extend the fabrication area that is the limit of traditional laser fabrication systems. The current world trend of PCB core technology development is focused on next generation semi-conductor package board and special high value-added PCB including a buildup board. Laser fabrication is necessary when the process microscopic line width and the line over the scanner area and it should be synchronized scanner-stage. This cannot be done with the current Step & Scanning method. To solve this problem synchronization of the stage and scanner was facilitated to continuously process a wide-area. The processing speed and laser fabrication quality were also improved.

Abstract: Objective: The aim of the study was to compare the manual tracing of lateral cephalometric radiographs with the use of cephalometric software obtained by 2 methods: use of a scanner and use of cameras to test the accuracy of measurement for clinical orthodontic diagnosis. Material and Methods: The original method of manual tracing was compared to 2 radiographic digitization methods: A) captured from a scanner, B) captured from digital cameras applied to 40 randomly selected cephalograms of orthodontic patients at Mahidol University. The digital images from cameras and scanner were analyzed with image processing software (CephSmile). The repeatability test was obtained for all methods, and the paired t-test determined the statistical significance between digitized images and original manual tracings for thirty-four measurements. Results: The paired t-test showed no significant differences among all 34 variables. Most mean differences were less than 0.25 mm and 0.25 degrees. Conclusion: The results demonstrated that there were no significant differences on measurement parameters for cephalometric analysis among manual tracing and computerized digital images from scanner and cameras.

Abstract: Aluminum alloys are extensively used in the automotive industry in response to increasing requirements for weight reduction in car body architecture. Laser welding of Al alloys has many advantages such as low heat input, narrow heat affected zone, minimal thermal distortion and flexibility. Recently, the development of high brightness lasers - thin disk lasers and fiber lasers enable long focal distance welding so that laser remote welding with scanning mirrors can be used in laser welding of Al alloys. In this study, laser remote welding was implemented to a heat shield part of an automobile by utilizing a 4kW disk laser and a 2-axis scanner. By replacing conventional resistance spot welding, the weld flange length could be reduced from 15mm to 8mm and a cycle time for each welding point could also be reduced from 3.5s to 0.6s.

Abstract: For the complexity of weld, the automatic inspecting for the tubular joints which are in working is difficult. Therefore the scanner which has three degrees of freedom for inspecting of large-diameter tubular joints was studied and manufactured based on the scanning principle of ultrasonic phased array. The following of probe to weld is realized by the simultaneous motion of two degrees of freedom and the pose between probe and weld is adjusted by the other degree of freedom. The control strategy of the scanner was provided. Experiments were made with scanner on reference blocks, the results indicate that the automatic ultrasonic phased array inspection is more excellent than the conventional ultrasonic inspection in reliability and repetition.

Abstract: Flat PZT cantilevers have been successfully fabricated from the Pt/Ti/PZT/Pt/Ti/SiO2/SOI multi-layered structure through MEMS technologies. A displacement of the tip of the cantilever driven at 6 V is measured to be 7.6 μm and the transverse piezoelectric constant calculated from the displacement is –103 pm/V. 1D optical scanners have been designed, simulated, fabricated and tested. The rotation angles of the mirror of the scanners were 60-70% of the simulated values.