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Title: Information hiding in boundary representation geometric models
Author: Salamon, Csaba
ISNI:       0000 0004 2740 4005
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2011
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The increasing mobility of computer aided design (CAD) data between subcontractors and distributed manufacturing facilities is creating a need to verify providence and protect the copyright of three-dimensional CAD models. Although watermarking technologies are well established for many types of digital media (e.g. music, image and video) no viable techniques have yet emerged for the high value solid boundary representation (B-rep) models used in 3D mechanical CAD systems. This thesis reviews some of the established approaches to watermarking 3D CAD objects, before describing the particular challenges inherent in the nature and use of B-rep data. After discussing some of the possible methods for incorporating watermarks into three dimensional data structures, an approach is described that subtly alters a B-rep model's geometric representation to incorporate a "transparent" signature. Furthermore, this thesis introduces a watermark assessment scheme and adequate test objects to enable objective benchmarking of the proposed method. In addition, it demonstrates the embedding and retrieval of text information, and investigates the robustness of the embedded watermark after a variety of transformation and modifications have been carried out. Test results show that the introduced parametric orientation (PO) watermark does not change the model's shape or file size, nor has any influence on the CAD model's capabilities. Considering the overall performance, PO-watermarking has shown to be a viable method for marking 3D B-rep CAD models. It works particularly well within a single CAD environment (i.e. company network) where no data is being translated into different formats, and is robust for everyday use. III
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available