Shape and deformation measurement using heterodyne range imaging technology

Range imaging is emerging as a promising alternative technology for applications that require non-contact visual inspection of object deformation and shape. Previously, we presented a solid-state full-field heterodyne range imaging device capable of capturing three-dimensional images with sub-millimetre range resolution. Using a heterodyne indirect time-of-flight configuration, this system simultaneously measures distance (and intensity), for each pixel in a cameras field of view. In this paper we briefly describe our range imaging system, and its principle of operation. By performing measurements on several metal objects, we demonstrate the potential capabilities of this technology for surface profiling and deformation measurement. In addition to verifying system performance, the reported examples highlight some important system limitations. With these in mind we subsequently discuss the further developments required to enable the use of this device as a robust and practical tool in non-destructive testing and measurement applications

Using a laser measurement system for monitoring morphological changes on the Strug rock fall, Slovenia

A medium-ranged high performance handheld reflectorless laser measurement system, was used for a morphological survey on the Strug rock fall in W Slovenia in the period from August 2003 to August 2004. The purpose was to evaluate its potential for monitoring ground surface changes in rock fall source areas and to help evaluating morphological changes by measuring distance from fixed points. In the area, 21 fixed geodetic points have been established. Altogether, seven measurement sets with more than 5500 points have been gathered in the rock fall area. Choosing a point cloud with a density of less than 1 point per 10 m(2) on a very rough rock fall surface failed to be a good solution. The changes on larger areas were shown by displacements of selected significantly large-sized rock blocks with a volume of several m(3). Because only smaller changes were observed between the single field series, the rock fall surface generally remained unchanged. Local surface changes of the order of 1 m or more, were clearly shown by measurements in the selected referenced cross sections. The usage of these cross sections gave a possibility to evaluate volumetric changes on the surface. The laser measurement system provided a good replacement for the classical terrestrial geodetic survey equipment, especially when performing remote monitoring of morphological changes in rock fall hazard zones, however, the case is different when fixed points are to be measured precisely

3D Scanner Using Infrared for Small Object

Three-Dimensional scanning is a method to convert various distances set into object visualization in 3-dimensional form. Developing a 3D scanner has various methods and techniques depending on the 3d scanner's purpose and the size of the object target. This research aims to build a prototype of a 3D scanner scanning small objects with dimensions maximum(10x7x23)cm. The study applied an a-three dimensional(3D) scanner using infrared and a motor to move the infrared upward to get Z-ordinate. The infrared is used to scan an object and visualize the result based on distance measurement by infrared. At the same time, the motor for rotating objects gets the (X, Y) ordinates. The object was placed in the center of the scanner, and the maximum distance of the object from infrared was 20cm. The model uses infrared to measure the object's distance, collect the result for each object's height, and visualize it in the graphic user interface. In this research, we tested the scanner with the distance between the object and infrared were 7 cm, 10 cm, 15 cm, and 20 cm. The best result was 80% accurate, with the distance between the object and the infrared being 10cm. The best result was obtained when the scanner was used on a cylindrical object and an object made of a non-glossy material. The design of this study is not recommended for objects with edge points and metal material

Measuring the accuracy of digitization of contactless scanners

Cílem práce je praktické ověření a stanovení přesnosti digitalizace bezkontaktních 3D skenerů, které jsou dostupné na oddělení TUL / KSA, v souladu s postupy používanými pro kalibraci (přejímací zkoušky) těchto zařízení. Součástí práce jsou informace o laboratorním vybavení potřebném k implementaci praktické části práce (3D bezkontaktní skener Atos III Triple Scan, Metra-Scan, Ein-scan, REV scan, Leica AT901-MR, SW GOM Inspect), o principech optické digitalizace a tak zvaných akceptačních testech. Implementace doporučených postupů pro testování přesnosti optických 3D skenerů je realizována na kalibračním standardu (etalonu), jehož nominální rozměry jsou určeny měřením na souřadnicovém měřicím stroji (CMM). S využitím standardu je stanovena přesnost digitalizace jednotlivých skenerů, výsledky jsou zpracovány, analyzovány a konfrontovány s údaji poskytnutými výrobci zařízení.The aim of the thesis is practical verification and determination of the accuracy of digitization of contactless 3D scanners which were available at the TUL/KSA department in accordance with the procedures used for calibration (acceptance tests) of these devices. The steps involved in this thesis are, to gain knowledge of laboratory equipment needed to implement the practical part of the work (3D contactless scanner such as Atos III Triple scan, Metra-Scan, Ein-scan, REV scan, Leica AT901-MR, SW GOM Inspect), with the principles of optical digitization and the so-called Acceptance tests. This thesis requires a Calibration standard, which is also termed Etalon that will enable the recommended procedures for testing the accuracy of optical 3D scanners to be implemented and determination of the nominal dimensions of the standard i.e., by CMM. By using this standard, the accuracy of digitization of individual scanners is determined and the results are processed and the accuracy results are compared with the data provided by the device manufacturer

Three-dimensional image surface acquisition in vertebrate paleontology: A review of principal techniques

Three-dimensional (3D) surface scanning includes techniques of image acquisition and image processing. Among the former, hardware devices (e.g., portable and non-portable scanners, camera) capture images from the target, whereas image processing is conducted via specialized software, in which acquired images are processed to merge them into a single 3D surface model. Image surface scanning comprises a wide variety of devices which incorporate different image acquisition techniques, all of them with potential high standards results. We describe four different scanning devices and techniques commonly used in vertebrate paleontology in order to compare them in terms of pros and cons, considering different variables, such as scanning time, post-processing time, costs and image resolution. The decision on which device to choose will depend on the budget available, the portability as well as the nature of the fossil material being analyzed (e.g., size, weight, accessibility). In the light of this, photogrammetry constitutes the image surface technique which fulfills these requirements, having the best cost-benefit relationship

2D-based indoor mobile laser scanning for construction digital mapping application

A common issue which occurs often in construction projects is how to determine the discrepancies between as-built or existing constructions and initial design. Physical manual measurement usually brings many of problems such as long measuring time, high labor consumption, and measurement error accumulation and in some cases lower accuracy. Therefore, more advanced technologies such as laser scanning and total station, which are used in geospatial mapping and surveying have been adopted in order to provide much more reliable and accurate measurements. However, technical and financial issues still constrain the widespread applications of well-known 3-dimensional (3D) terrestrial and aerial laser scanning, such as high equipment cost, complex pre-preparation, inconvenience of use and spatial limitation. This paper aims to introduce an innovative laser scanning method for indoor construction mapping. This method integrates an IMU-GPS positioning approach with a more convenient, more time saving and lower costed 2-dimensional (2D) laser scanner to realize indoor mobile 3D mapping for construction model creation, which can be integrated with Building Information Modelling (BIM) design in order to realize the applications, such as quality control of as-built construction or indoor mapping of existing building. Although compared with traditional 3D laser scanning, its accuracy and reliability cannot reach such a high level currently, experimental results still indicate feasibility, reliability and potential capability of this indoor mobile laser scanning method. It is hoped that this method will be further improved to substitute the stationary 3D laser scanning for narrow and limited construction spatial mapping in the near future

Aspects of Cave Data Use in a GIS

This paper gives an overview about the theoretical and technical aspects of a geographic information system (GIS), which can provide a framework for scientific (hydrological, morphological, geological, etc.) analysis of cave survey data. It is emphasized that a GIS containing archive cave data is important because the information often is irreplaceable (the cave environment has changed), or the resurveying may harm the cave. Thus, it is proposed that a GIS of cave data be multidisciplinary to avoid unnecessary resurveying of caves. To produce such a system, one has to bear in mind many aspects, which is not always evident for the practicing scientists. Cave surveys produce spatial data, either it was measured with measure tape and compass or with a LiDAR station. It is a major issue in cave data processing that the spatial data produced in various surveys do not fit together due to the different methods and coordinate systems, or because of the various data types, which make it hard to syllabize the similarities between different sets of data. The paper focus on how to work with archive and new survey data, and how to handle maps, scans, and sampling data in one information system. From the aspect of data transfer, three main functionalities of a GIS are distinguished: processing, storing, and representation of the information. Discussing the theoretical and practical backgrounds of these functionalities, the paper presents the best practices of building a GIS from archive and newly measured data, emphasizing the importance of procedures like data management, quality control, and automation. The paper shed lights to the various data types that are usually related to cave surveys, to help cave scientist to control the data management and understand (and apply) the automatisms. Also, the probable technical parameters of future cave surveillance systems are discussed

Application of handheld laser scanning technology for forest inventory purposes in the NE Turkey

Forest inventory (FI) is the most challenging stage of forest management and planning process. Therefore, in situ surveys are often reinforced by modern remote sensing (RS) methods for collecting forestry-related data more efficiently. This study tests a state-of-the-art data collection method for practical use in the Turkish FI system for the first time. To this end, forest sampling plots were conventionally measured to collect dendrometric data from 437 trees in Artvin and Saçınka Forest Enterprises. Then, each plot was scanned using a handheld mobile laser scanning (HMLS) instrument. Finally, HMLS data were compared against ground measurements via basic FI measures. Based on statistical tests, no apparent differences were found between the two datasets at the plot level (P 0.97; P < 0.01). Residual analysis showed that both positive and negative errors had a homogeneous distribution, except for plot 8 where tree stems were in irregular shapes due to anthropogenic pressures. When all plots’ data were aggregated, average values for the number of trees, basal area, and timber volume were estimated as 535 trees/ha–1, 49.6 m2/ha–1, and 499.7 m3/ha–1, respectively. Furthermore, secondary measures such as the number of saplings and slope were successfully retrieved using HMLS method. The highest overestimation was in timber volume with less than 10% difference at the landscape level. The differences were attributed to poor data quality of conventional measurements, as well as marginal site conditions in some plots. We concluded that the HMLS method met the accuracy standards for most FI measures, except for stand height. Thus, the Turkish FI system could benefit from this novel technology, which in turn supports the implementation of sound forest management and planning

3D Acquisition of Archaeological Ceramics and Web-Based 3D Data Storage

Motivated by the requirements of modern archaeology, we are developing an automated system for archaeological classification and reconstruction of ceramics. The goal is to create a tool that satisfies the criteria of accuracy, performance (findings/hour), robustness, transportability, overall costs, and careful handling of the findings. Following our previous work, we present new achievements on the documentation steps for 3D acquisition, 3D data processing, and 3D reconstruction. We have improved our system so that it can handle large quantities of ceramic fragments efficiently and computes a more robust orientation of a fragment. In order to store the sherd data acquired and hold all the information necessary to reconstruct a complete vessel, a database for archaeological fragments was developed. We will demonstrate practical experiments and results undertaken onsite at different excavations in Israel and Peru

Three-dimensional scanning as a means of archiving sculptures

Thesis (M. Tech. Design technology) -- Central University of Technology, Free State, 2011This dissertation outlines a procedural scanning process using the portable ZCorporation ZScanner® 700 and provides an overview of the developments surrounding 3D scanning technologies; specifically their application for archiving Cultural Heritage sites and projects. The procedural scanning process is structured around the identification of 3D data recording variables applicable to the digital archiving of an art museum’s collection of sculptures. The outlining of a procedural 3D scanning environment supports the developing technology of 3D digital archiving in view of artefact preservation and interactive digital accessibility. Presented in this paper are several case studies that record 3D scanning variables such as texture, scale, surface detail, light and data conversion applicable to varied sculptural surfaces and form. Emphasis is placed on the procedural documentation and the anomalies associated with the physical object, equipment used, and the scanning environment. In support of the above, the Cultural Heritage projects that are analyzed prove that 3D portable scanning could provide digital longevity and access to previously inaccessible arenas for a diverse range of digital data archiving infrastructures. The development of 3D data acquisition via scanning, CAD modelling and 2D to 3D data file conversion technologies as well as the aesthetic effect and standards of digital archiving in terms of the artwork – viewer relationship and international practices or criterions of 3D digitizing are analysed. These projects indicate the significant use of optical 3D scanning techniques and their employ on renowned historical artefacts thus emphasizing their importance, safety and effectiveness. The aim with this research is to establish that the innovation and future implications of 3D scanning could be instrumental to future technological advancement in an interdisciplinary capacity to further data capture and processing in various Cultural Heritage diagnostic applications