PMP-Based Micro-3D Dental Measuring Technology

2012 ◽  
Vol 192 ◽  
pp. 310-317
Author(s):  
Zhong Wei Li ◽  
Chao Ma ◽  
Chun Li Liu ◽  
Cong Jun Wang ◽  
Kai Zhong ◽  
...  
Keyword(s):  
Structured Light ◽  
Signal Transmission ◽  
Phase Shifting ◽  
Scanning System ◽  
3D Measurement ◽  
Long Distance ◽  
Measurement Principle ◽  
Scope Of Application ◽  
3D Profile ◽  
Distance Signal

Based on the structured light measurement principle, digital fringes projection technology and phase-shifting measuring technology, specific to the 3D profile of some tiny objects like teeth, in this paper we proposes a 3D scanning system which was directly used for intraoral dental measurement utilizing the merits of flexible and long distance signal transmission of the fiber image bundle. The structured light is projected out from DLP LightCommander produced by Texas Instruments Company, shrunk via telecentric imaging lens, conveyed in fiber image bundle. Utilizing the transformational relation between single-camera and projector, afterwards, the 3D profile of teeth is obtained by reconstructing the acquisition images in electronic endoscope. The feasibility of this system has been testified in our experiments. It satisfies the requirements of miniaturization, directness and flexibility; expands the scope of application of micro-3D measurement with structured light in dental clinical practice.

Long-Distance Signal Transmission in Trees

2006 ◽  
pp. 333-349
Author(s):  
Stefano Mancuso ◽  
Sergio Mugnai
Keyword(s):  
Signal Transmission ◽  
Long Distance ◽  
Distance Signal

scholarly journals STRUCTURED LIGHT BASED 3D SCANNING FOR SPECULAR SURFACE BY THE COMBINATION OF GRAY CODE AND PHASE SHIFTING

2016 ◽  
Vol XLI-B3 ◽  
pp. 137-142
Author(s):  
Yujia Zhang ◽  
Alper Yilmaz
Keyword(s):  
High Frequency ◽  
Structured Light ◽  
Gray Code ◽  
3D Scanning ◽  
Phase Shifting ◽  
Scanning System ◽  
High Quality ◽  
Specular Surface ◽  
Combination Technique ◽  
Indirect Illumination

Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new combined coding method.

Influence of Coating Spray on Surface Measurement Using 3D Optical Scanning Systems

2019 ◽  
Author(s):  
Yuhang Yang ◽  
Siyuan Chen ◽  
Letao Wang ◽  
Jingying He ◽  
Shang-Ming Wang ◽  
...  
Keyword(s):  
Structured Light ◽  
Spray Coating ◽  
Surface Measurement ◽  
Scanning System ◽  
3D Measurement ◽  
Optical Scanning ◽  
Wide Range ◽  
Structured Light Scanning ◽  
3D Measurement System ◽  
Scanning Systems

Abstract High-resolution 3D measurement is crucial for a wide range of applications in manufacturing. With the recent development of optical technologies, the performance of many 3D scanning systems has entered the practical range for object digitizing, reverse engineering, quality control, and many other manufacturing applications. In order to extend the measurement capability to reflective or transparent surfaces, a common practice for reducing the unwanted reflection and refraction is to coat the surfaces with micro-particle spray. There is, however, limited discussion about the influence of coating spray on the resulted measurement precision of 3D optical scanning systems, and due to lack of standardized procedure for spray coating, the variability caused by different operators in surface measurement remains to be examined. This paper investigates the 3D data acquisition of spray-coated surfaces with a structured-light scanning system through experiments and statistical analysis. Both surface roughness and spatial statistics are used to quantitatively evaluate the characteristics of the 3D measurement system. Gauge R&R study is conducted to determine measurement repeatability and reproducibility. The results demonstrate that both the number of spray pass and the skill of the individual operator can significantly affect the performance of the structured-light scanning system. Other pertinent suggestions for the operation of 3D optical scanning systems with spray coating are also provided.

Long-Distance Signal Transmission in Trees

2007 ◽  
pp. 333-349 ◽  
Author(s):  
Stefano Mancuso ◽  
Sergio Mugnai
Keyword(s):  
Signal Transmission ◽  
Long Distance ◽  
Distance Signal
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