<p>Laser scanners in combination with devices for accurate orientation like Coordinate Measuring Machines (CMM) are often used in Geometric Reverse Engineering (GRE) to measure point data. The industrial robot as a device for orientation has relatively low accuracy but the advantage of being numerically controlled, fast, flexible, rather cheap and compatible with industrial environments. It is therefore of interest to investigate if it can be used in this application.</p><p>This thesis will describe a measuring system consisting of a laser profile scanner mounted on an industrial robot with a turntable. It will also give an introduction to Geometric Reverse Engineering (GRE) and describe an automatic GRE process using this measuring system. The thesis also presents a detailed accuracy analysis supported by experiments that show how 2D profile data can be used to achieve a higher accuracy than the basic accuracy of the robot. The core topic of the thesis is the investigation of a new technique for planar segmentation. The new method is implemented in the GRE system and compared with an implementation of a more traditional method.</p><p>Results from practical experiments show that the new method is much faster while equally accurate or better.</p>

Laser scanners in combination with devices for accurate orientation like Coordinate Measuring Machines (CMM) are often used in Geometric Reverse Engineering (GRE) to measure point data. The industrial robot as a device for orientation has relatively low accuracy but the advantage of being numerically controlled, fast, flexible, rather cheap and compatible with industrial environments. It is therefore of interest to investigate if it can be used in this application. This thesis will describe a measuring system consisting of a laser profile scanner mounted on an industrial robot with a turntable. It will also give an introduction to Geometric Reverse Engineering (GRE) and describe an automatic GRE process using this measuring system. The thesis also presents a detailed accuracy analysis supported by experiments that show how 2D profile data can be used to achieve a higher accuracy than the basic accuracy of the robot. The core topic of the thesis is the investigation of a new technique for planar segmentation. The new method is implemented in the GRE system and compared with an implementation of a more traditional method. Results from practical experiments show that the new method is much faster while equally accurate or better.

Inom området maskinteknik finns idag ett stort intresse för Reverse Engineering med hjälp av 3Dskanning. Tekniken utgår ifrån att skapa Computer-Aided-Design (CAD) modeller av reala objekt. Föreliggande projekt utfördes vid institutionen för tillämpad fysik och elektronik vid Umeå universitetet i syfte att utvärdera prestationen av Reverse Engineering av objekt som är utmanade at rita direkt i CAD-program. Fyra olika fysiska objekt valdes för analys: en bult, en tolvkantshylsa, en propeller och ett snäckhjul; det sistnämnda tillhandahållen av företaget Rototilt Group AB. Objekten avbildades med en 3D-skannare som använder sig av metoden strukturerat ljus för att läsa in objektens form och har en noggrannhet på 0,04 mm. De 3Davbildade objekten redigerades sedan och CAD-ritningar skapades. Slutligen skrevs CADmodellerna ut med hjälp av en 3D-skrivare och en toleransanalys med gränsvärdet 0,2 mmutfördes för att jämföra dimensionerna av originalobjekten, de olika digitala modellerna samt de utskrivna objekten. Resultatet visar att Reverse Engineering (med vissa begränsningar) är en bra metod för objekt som är utmanade att modellera i CAD. Med tekniken kan fysiska objektrekonstrueras till CAD-modeller snabbt och med hög noggrannhet. / In the field of mechanical engineering, there is an increasing interest in Reverse Engineering using 3D-scanning. The technology is based on creating Computer-Aided-Design (CAD) models of real objects. The present project was carried out at the Department of Applied Physics and Electronics at Umeå University in order to evaluate the performance of Reverse Engineering of objects that are challenging to draw directly in CAD programs. Four different physical objects were selected for analysis: a bolt, a hex socket, a propeller and a worm wheel; the latter provided by the company Rototilt Group AB. A structured light 3D-scanner with a specified accuracy of 0,04 mm was used to image the objects. The 3D images were then post-processed and transferred to CAD software to create the CAD drawings. Finally, the CAD-models were printed with a 3D printer and a tolerance analysis with a limit of 0,2 mm was performed to compare the dimensions of the original objects, the different digital models and the printed objects. The results show that Reverse Engineering (with some limitations) is a good method for objects that are difficult to model in CAD. The technique is well-suited to reconstruct physical objects into CAD-models quickly and with high accuracy.