Mariza Kormann

An intelligent real time 3D vision system for robotic welding tasks

MARWIN is a top-level robot control system that has been designed for automatic robot welding tasks. It extracts welding parameters and calculates robot trajectories directly from CAD models which are then verified by real-time 3D scanning and registration. MARWINs 3D computer vision provides a user-centred robot environment in which a task is specified by the user by simply confirming and/or adjusting suggested parameters and welding sequences. The focus of this paper is on describing a mathematical formulation for fast 3D reconstruction using structured light together with the mechanical design and testing of the 3D vision system and show how such technologies can be exploited in robot welding tasks.

Structured light techniques for 3D surface reconstruction in robotic tasks

Robotic tasks such as navigation and path planning can be greatly enhanced by a vision system capable of providing depth perception from fast and accurate 3D surface reconstruction. Focused on robotic welding tasks we present a comparative analysis of a novel mathematical formulation for 3D surface reconstruction and discuss image processing requirements for reliable detection of patterns in the image. Models are presented for a parallel and angled configurations of light source and image sensor. It is shown that the parallel arrangement requires 35% fewer arithmetic operations to compute a point cloud in 3D being thus more appropriate for real-time applications. Experiments show that the technique is appropriate to scan a variety of surfaces and, in particular, the intended metallic parts for robotic welding tasks.

Robot Trajectory Planning Using OLP and Structured Light 3D Machine Vision

This paper proposes a new methodology for robotic offline programming (OLP) addressing the issue of automatic program generation directly from 3D CAD models and verification through online 3D reconstruction. Limitations of current OLP include manufacturing tolerances between CAD and workpieces and inaccuracies in workpiece placement and modelled work cell. These issues are addressed and demonstrated through surface scanning, registration, and global and local error estimation. The method allows the robot to adjust the welding path designed from the CAD model to the actual workpiece. Alternatively, for non-repetitive tasks and where a CAD model is not available, it is possible to interactively define the path online over the scanned surface.

A case study of 3D technologies in higher education: Scanning the metalwork collection of museums sheffield and its implications to teaching and learning

This paper describes results from the fast 3D scanning project conducted at Sheffield Hallam University in collaboration with Museums Sheffield. We focus on the technological aspects that are required for fast scanning and discuss the steps in the process from scanning and noise removal to 3D post-processing and how the resulting 3D models can be made available on a standard web browser. We also discuss some implications to the teaching and learning of 3D technologies to undergraduate and postgraduate courses.

Methods for developing 3D visualizations of archaeological data: a case study of the Early Bronze Age Helike Corridor House

ABSTRACT The Digital Helike Project aims at the digitization of archaeological data from the Helike Project, Achaia, Greece. This paper advances understanding of Early Bronze Age house building techniques with focus on corridor houses. The Helike Corridor House is a fine example of an architectural style of the Early Helladic period EH II/Early EH III on the Greek mainland and it is used here as a case study. A methodology for 3D reconstruction is described supporting both structural integrity simulations and advanced visualization studies. The paper focuses on three aspects: firstly, it highlights technological innovations in the Bronze Age period by drawing attention to structural integrity studies recently carried out by the research team; secondly, it describes a methodology for building fully geo-referenced 3D models supporting structural integrity studies and visualization on GIS-Geographic Information Systems; and thirdly, it leads to the universal access of data and visualization over the Internet through the selection of appropriate open source, open standards and freely available tools and applications. The methodologies proposed here deepen insights on archaeological data enabling new inferences and knowledge to be gained through the implementation of universally shared low cost applications.