LASER Scanning and 3D Measurement Techniques
- Deformation Analysis of a warped ship propeller
- © Daniel Wujanz
LASER Scanning and 3D Measurement Techniques (3rd
Semester, 3 ECTS points)
Laser Scanning and other contemporary measurement techniques like structured light approaches have undoubtedly been accepted as powerful surveying instruments by many commercial users as well as in science. Yet the academic education is nearly restricted to a few projected slides or a couple of sketches on a black board. Practical exercises related to this topic within courses usually consist of a short demo by a staff member completely disregarding active learning processes and experiences.Most modern enterprises are usually not interested in personnel that are only able to derive theoretical matter. Commonly they are looking for people that have practical experience, sound theoretical knowledge and innovative ideas that, if all these ingredients are mixed together, can be turned into a new product or that can solve given problems. Motivated by these requirements a concept has been developed that consists of three major elements:
- Practical Exercises: The students actively solve a given problem by applying different sensors
- Post Processing: All captured data has to be turned into a requested product. Furthermore theoretical tasks have to be solved by reconsidering knowledge from the lectures and practical exercises
- Programming Exercises: Several known algorithms have to be implemented in their basic form. Then the students have to improve the initial produced results
Sample Project - Dynamics of Maritime Systems – Inspection of a free form shape:
In cooperation with the working group Dynamics of Maritime Systems , led by Prof. Andres Cura-Hochbaum, the prototype of a scale reduced ship propeller has been analysed. Christian Eckl, a specialist for hydrodynamics, raised the assumption that one of the blades of the propeller was warped which came to light as slightly visible anomalies in hydrodynamic tests in closed water tanks under stroboscopic light. At first the students had to prepare the propeller for scanning with a structured light device due to the shininess of the object. To achieve an accuracy of roughly 1/10 mm a certain setup of the survey instrument had to be chosen and calibrated. The measurement itself took about 2 hours and had then been converted into a closed surface representation through NURBS (Non uniform rational B-spline) modelling. This result was then brought into an inspection software (see figure on top right) and compared to a CAD of which the propeller had been machined.
3D Measurement techniques are a rapidly increasing market that spreads over a variety of different fields of applications: Topographical Surveys, Deformation Analysis, As-Built Documentation, Rapid Prototyping & Reverse Engineering, Virtual Reality, Engineering Surveying, Industrial Surveys, Machine Control, Human- Machine Interaction, ... The necessity of well trained personnel will, as a result of the first raised point, increase in all possible areas of these techniques ranging from data acquisition, research and development to post processing where we then possibly encounter needs and demands from interdisciplinary fields.
Applied Sensors and Techniques:
- Zoller und Fröhlich Imager 5006 LASER Scanner
- Leica C10 LASER Scanner
- Microsoft Kinect Gaming Controller
- GOM ATOS I Structured Light Scanner
- GOM TRITOP Close Range Photogrammetry Solution
- 3D Printers (Powder and Plastic Grain)
- 3 Wall Virtual Reality Cave
The last four entries are provided within a tight cooperation by the 3D Laboratory .