Recognizing the Design Patterns of Complex Vaults: Drawing, Survey and Modeling. Experiments on Palazzo Mazzonis’ Atrium in Turin

This paper shows the results of research advances on complex vaulted systems produced by the integration of laser scanner survey techniques and three-dimensional modeling for the geometric interpretation of built architecture to recognizing the geometric matrices of the design conception. The integration between TLS techniques and digital modeling methods led to the definition of new workflows, aimed at optimizing the use of data and at refining the quality of the geometrical interpretation. The process incorporates the traditional activities of freehand drawing of eydotipes, aimed at a deep understanding of the peculiar characteristics of the artifact. In particular, from these procedures new opportunities for the research arise to better understand the relationships between survey data, geometric matrices and compositional rules. The case study presented here, the atrium of Palazzo Mazzonis in Turin was chosen among a small number of atria that present characteristics of originality and uniqueness in a panorama of realizations strongly characterized by compliance with well-established compositional schemes

The Design and Construction of a Green Laser and Fabry-Perot Cavity System for Jefferson Lab\u27s Hall A Compton Polarimeter

A high finesse Fabry-Perot cavity with a frequency doubled green laser (CW, 532 nm) have been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry project in spring of 2010. It provides a high intensity circularly polarized photon target for measuring the polarization of electron beam with energies from 1.0 GeV to 11.0 GeV in a nondestructive manner. The IR beam (CW, 1064 nm) from a Ytterbium doped fiber laser amplifier seeded by a Nd:YAG narrow linewidth NPRO laser is frequency doubled in by a single-pass Periodically Poled Lithium Niobate (PPMgLN) crystal. The maximum achieved green power at 5 W IR pump power was 1.74 W with a total conversion efficiency of 34.8%. The frequency locking of this green light to the cavity resonance frequency is achieved by giving a feedback to Nd:YAG crystal via laser piezoelectric (PZT) actuator by Pound-Drever-Hall (PDH) technique. The data shows the maximum amplification gain of our cavity is about 4,000 with a corresponding maximum intra-cavity power of 3.7 kW. The polarization transfer function has been measured in order to determine the intra-cavity laser polarization within the measurement uncertainty of 0.7%. The PREx experiment at JLab, used this system for the first time and achieved 1.0% precision in electron beam polarization measurement at 1.0 GeV

3d Scanning And The Impact Of The Digital Thread On Manufacturing And Re-Manufacturing Applications

3D laser line scanners are becoming a powerful technology for capturing point cloud datasets and collecting dimensional information for many objects. However, the use of point cloud is limited due to many factors. These include the lack of on deep understanding of the effect of point cloud parameters on scan quality. This knowledge is critical to gaining an understanding of the measurement in point cloud. Currently, there are no adequate measurement procedures for 3D scanners. There is a need for standardized measurement procedures to evaluate 3D scanner accuracy due to uncertainties in 3D scanning, such as surface quality, surface orientation and scan depth [6]. The lack of standardized procedures does not allow the technology to be fully automated and used in manufacturing facilities that would allow 100% in-line inspection. In this dissertation I worked on accomplishing four tasks that will achieve the objective of having a standardized measurement procedure that is critical to develop an automated laser scanning system to avoid variations and have consistent data capable of identifying defects. The four tasks are: (1) linking the robot workspace with the scanner workspace; (2) studying the effect of the scanning speed and the resolution on point cloud quality by conducting an experiment with systematically varied scan parameters on scan quality; (3) studying the overall error of that is associated with the transformation of the point cloud in a remanufacturing facility using additive manufacturing. The parameters that were tested are the effect of view angle, standoff distance, speed, and resolution. Knowing the effect of these parameters is important in order to generate the scan path that provides the best coverage and quality of points collected. There is also a need to know the impact of all the scanning parameters especially the speed and the resolution; (4) modeling a machine learning tool to optimize the parameters of different scanning techniques after collecting the scanning results to select the optimal ones that provide the best scan quality. With the success of this work, the advancement and practice of automated quality monitoring in manufacturing will increase

A Novel LiDAR-Based Instrument for High-Throughput, 3D Measurement of Morphological Traits in Maize and Sorghum

Recently, imaged-based approaches have developed rapidly for high-throughput plant phenotyping (HTPP). Imaging reduces a 3D plant into 2D images, which makes the retrieval of plant morphological traits challenging. We developed a novel LiDAR-based phenotyping instrument to generate 3D point clouds of single plants. The instrument combined a LiDAR scanner with a precision rotation stage on which an individual plant was placed. A LabVIEW program was developed to control the scanning and rotation motion, synchronize the measurements from both devices, and capture a 360◦ view point cloud. A data processing pipeline was developed for noise removal, voxelization, triangulation, and plant leaf surface reconstruction. Once the leaf digital surfaces were reconstructed, plant morphological traits, including individual and total leaf area, leaf inclination angle, and leaf angular distribution, were derived. The system was tested with maize and sorghum plants. The results showed that leaf area measurements by the instrument were highly correlated with the reference methods (R2 \u3e 0.91 for individual leaf area; R2 \u3e 0.95 for total leaf area of each plant). Leaf angular distributions of the two species were also derived. This instrument could fill a critical technological gap for indoor HTPP of plant morphological traits in 3D

Intelligent laser scanning for computer aided manufacture.

Reverse engineering requires the acquisition of large amounts of data describing the surface of an object, sufficient to replicate that object accurately using appropriate fabrication techniques. This is important within a wide range of commercial and scientific fields where CAD models may be unavailable for parts that must be duplicated or modified, or where a physical model is used as a prototype. The three-dimensional digitisation of objects is an essential first step in reverse engineering. Optical triangulation laser sensors are one of the most popular and common non-contact methods used in the data acquisition process today. They provide the means for high resolution scanning of complex objects. Multiple scans of the object are usually required to capture the full 3D profile of the object. A number of factors, including scan resolution, system optics and the precision of the mechanical parts comprising the system may affect the accuracy of the process. A single perspective optical triangulation sensor provides an inexpensive method for the acquisition of 3D range image data