Papers by Keyword: Scanning

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Authors: Qian Guo, Guang Xue Chen, Jian Luo, Qi Feng Chen, Zheng Guo He
Abstract: In this letter, a digital watermarking method which combines the singular value decomposition (SVD) and the discrete cosine transform (DCT) is presented. First of all, The Arnold scrambling and the DCT are performed on the watermark and the original image, respectively. The SVD transform is performed on the image when scrambled watermark is embedded, then the watermarked image is formed. Finally, we extract watermark from the image which is handled by halftone screens. The experimental results show that this method can achieve the highest possible robustness without losing the transparency. Also it can anti printing and scanning. All the processes do not require any additional equipment. It will bring new hope to the field of anti-counterfeiting printing with singular value decomposition is applied to the half-tone image area.
Authors: Yun Kang Ji, Fang Nan Liu
Abstract: The paper analyzes the forms of different probe pole distribution automatic detection equipment inspection speed setting principle; Combined the common failure modes of several kinds of probe or channel, in order to ensure the detection achieve 100% scanning coverage and discusses the detection speed setting problem.
Authors: Gheorghe Nagit, Andrei Marius Mihalache
Abstract: The study aims to propose an alternative method of segmentation of digitized data. It begins by layering the item's surface. It analyzes the nodes inside a point cloud to detect any consistent shape change. If one detected, then it holds it and looks for the next one which may describe a possible shape change. The points between those two are classified and marked as part of the shape change curvature line. The method remembers the marked points and holds them as central nodes which will later form reference regions. It uses normal vectors behavior methods to detect shape changes along X and Y axis. As any other direction would not be detectable by the bi-dimensional approach it then introduces a morphological parameter capable on its own to fully describe the curvature variation of a given item's surface by means of Gauss's curvature. To evaluate curvature variation, the method proposes that the central node's curvature should be compared with every found limit points. Because of the noise present in any points cloud it establishes a threshold value beyond which points may describe accurately any shape change. This procedure takes place for all analyzed reference regions and collects only those who have a greater value than the threshold one. This considerations may be extrapolated to other types of geometries as well, as it is the case with cylinders or cones.
Authors: Chia Ching Wang, Po Chi Hu, Chung Li Tsai, Sung Long Chen
Abstract: A dental scanning system was developed using multiple light strips of DPSSL (Diode-Pumped Solid-State Laser) sources with a video capturing module of one CMOS camera. The laser line scanning method is less sensitive to the surface conditions of the materials for measurement compared with the structured light scanning method, and a multi-lines scanning design is used to improve the scanning efficiency. The study uses DPSSL lines to scan over the teeth models either by sequence or by sections, which determines the actual time spent. For an object within 100x100mm projective area, the scanning time is about 10 minutes with ±0.05 mm accuracy on a gypsum teeth model using sequential scanning. The results show high accuracy and efficiency scanning teeth models with multi-lines projecting module integrated within, and is possible for further improvement in the growing digital-dental industry.
Authors: Elvis K. Tiburu, Heidimarie N.A. Fleischer, Edmund O. Aidoo, Ali Salifu, Bernard O. Asimeng, Han Zhou
Abstract: This work reports evidence of the synthesis of zeolite A at two different temperatures (60 °C and 105 °C) from kaolin. XRD spectral analysis revealed percent crystallinity of 74 ± 2 and 71 ± 3 in LTA60 and LTA105 respectively. The average crystallize size of LTA60 and LTA105 was also estimated using Scherrer’s equation to be 57 nm. FTIR analysis showed signature peaks characteristics of zeolite A in the two materials, except the appearance of absorbance peak at 2380 cm− 1 in the LTA60 spectrum which was not observed in LTA105. Nitrogen porosity measurements of LTA60 and LTA105 gave the following parameters: average pore width of 2.45 and 1.01 nm respectively for LTA60 and LTA105, surface areas of 19.18 and 8.00 m2/g and pore volume of 0.012 and 0.002 cm3/g in that order. The influence of the materials on HeLa cancer cell growth was also investigated and the results showed differential inhibitory effects with LTA60 revealing pronounced inhibitory effects compared to LTA105 after 72 hours of cell incubation. This studies highlighted the importance of crystallization conditions that could influence the physicochemical parameters including structure, porosity, size, and morphology of zeolite materials on cell activity. The work also provided unique opportunities for utilizing natural deposits of kaolin globally to fabricate biomimetic materials for various biological applications.
Authors: Chi Zhang, Hu Huang
Abstract: A laser ranging system for scanning detection based on phase shift ranging technology and a MEMS mirror for space detection and measurement is presented in this paper. The laser ranging system is mainly composed of a modulation module, a laser, a MEMS mirror, a photo-electric conversion module and a signal processing module. The phase shift ranging method is used to measure the relative range to the target. The MEMS mirror is a micro scanner with two DOF, which is used to change the direction of the emitted laser beam. The modulated laser beam is emitted through the MEMS mirror and reflected from the target. The relative range is calculated by the phase shift between the emitted beam and the reflected beam. The experimental results indicate that the measurement accuracy is 0.10 m in static status and 0.17 m in scanning status in the range of 3 m. The differences between the static and the scanning status are analyzed and improvements are proposed.
Authors: Chi Zhang
Abstract: A 3D shape measurement system based on a laser rangefinder and a two-dimensional MEMS mirror is presented in this paper. According to the requirement of surface profile measurement, the 3D shape measurement system is mainly composed of a laser module, a two-dimensional MEMS mirror, a ranging module, an orientation module and an image composition module. Based on the MEMS scanning technology and phase shift ranging method, the surface profile of the target can be acquired by the measurement system. For the coupled scanning mode, the scanning pattern is simulated in Lissajous figure and the condition of covering all the field of view is analyzed. The simulation results show that the 3D shape measurement system based on the laser rangefinder and the two-dimensional MEMS mirror can realize the measurement the surface profile of the target in all the field of view.
Authors: Vishal John Mathai, Harshit K. Dave, Keyur P. Desai
Abstract: The design and manufacturing of complex shaped 3D features have a wide range of applications in todays manufacturing industries. With machining of hard materials continues to attract much interest in this field, EDM remains an indispensable process to carry out this purpose despite its limitations compared to conventional machining processes in terms of material removal rate and surface quality. Many process improvement techniques have been reported by researchers to overcome these limitations and out of them, incorporation of tool electrode kinematics is observed to have a significant effect. In the present investigation, an attempt has been made to study the effectiveness of two different tool motions in the generation of non-circular cavities. Tool electrode is moved on planetary and diagonal paths during this study. Effects of various electrical and non-electrical parameters on EDM responses have been studied. Current, pulse ON time and voltage are considered as the electrical parameters while tool kinematics parameters like tool path offset and scanning speed have been selected as the non-electrical parameters. Experiments have been carried out the study the effect of tool movement on planetary and diagonal path on different response characteristics viz. Material removal rateand Wear Ratio. It has been observed that planetary motion is a better strategy than diagonal motion for the generation of non-circular cavities in terms of achievement of the response characteristics. The results observed are critically discussed.
Authors: Kyung Young Jhang, Jee Hong Jung, Hong Joon Kim, Min Kwan Hyeon
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