Nenad Grujović2, Dejan Divac
AR ASSISTED SYSTEM FOR PART REMOVAL
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| AR ASSISTED SYSTEM FOR PART REMOVAL
The solution presented here is designed to visually assist technicians in part removal procedure using marker-based AR that supports both handheld and head-mounted devices. The parts layout in build chamber setup by technician using ZPrint software represents input for visualization. The platform for AR is ARToolKit, a reliable GNU library for single-camera applications. 
Fig.5. Structure of the system The structure of the system is illustrated in Figure 5. The central part is the visualization module, which can be hosted both on head-mounted or handheld devices. This module uses data from parser module to generate scene for rendering based on marker orientation and position. The parser module is used to convert build layout to geometry data used in visualization module. A build batch consists of multiple parts arranged within build volume. It holds information on part geometry and layout. Since native format for saving build in ZPrint software is undocumented binary file, the technician needs to export the build to STL file, using menu command File > Export STL. The resulting file represents input data for the parser module, which converts triangle list into object geometry used by visualization module. 
Fig.6. AR assisted part removal Up to 4 fiducial markers may be used by visualization module, so that the technician can freely move while extracting printed parts. It is only necessary that at least one marker is always in field of view, so marker placement is important when preparing the system. By using special markers, it is possible to calibrate the system through guided procedure. The calibration is performed in order to establish reference coordinate system for visualization. Once reference coordinate system is established, the system will require subsequent calibration only if the marker placement changes. The system supports the use of either head-mounted or mobile AR devices. When using head-mounted AR device, the technician is free to move while extracting printed parts. The overlaid image of printed parts guides the technician in process of part removal, thus reducing the risk of damaging the parts buried in loose powder. When using the mobile AR device, the technician needs to periodically check part layout because using the AR device interferes with handling the other equipment. Nevertheless, for more complex build layouts even sporadic use of AR helps the technician to plan the part removal and reduce the associated risks. Directory: end end -> Chinese Wind Energy Disad end -> George huntington, M. D. Charles s. Stevenson bulletin of the institute of the history of medicine end -> Endi 2011 / Daniel/Jason/Kevin/Marc/MiHe/Parth/Simrun end -> - end -> Unit IV: End of the Cold War and Contemporary America The Americans end -> Index 1 shell 2 end -> A. background end -> End Times Colloquium 23-25 July 2014 Wits Club, West Campus, University of the Witwatersrand Download 0.8 Mb. Share with your friends:
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