Cardiff University School of Computer Science & Informatics Automatic Semantic and Geometric Enrichment of CityGML 3D Building Models of varying Architectural Styles with HOG-based Template Matching Jonathan Slade Submitted in part fulfilment of the requirements for the degree of Doctor of Philosophy in Computer Science at Cardiff University, January 31st, 2018 DECLARATION This work has not been submitted in substance for any other degree or award at this or any other university or place of learning, nor is being submitted concurrently in candidature for any degree or other award. Signed ………………………………………… (candidate) Date …………………. STATEMENT 1 This thesis is being submitted in partial fulfillment of the requirements for the degree of PhD……(insert MCh, MD, MPhil, PhD etc, as appropriate) Signed ………………………………………… (candidate) Date …………………. STATEMENT 2 This thesis is the result of my own independent work/investigation, except where otherwise stated, and the thesis has not been edited by a third party beyond what is permitted by Cardiff University’s Policy on the Use of Third Party Editors by Research Degree Students. Other sources are acknowledged by explicit references. The views expressed are my own. Signed ………………………………………… (candidate) Date …………………. STATEMENT 3 I hereby give consent for my thesis, if accepted, to be available online in the University’s Open Access repository and for inter-library loan, and for the title and summary to be made available to outside organisations. Signed ………………………………………… (candidate) Date …………………. STATEMENT 4: PREVIOUSLY APPROVED BAR ON ACCESS I hereby give consent for my thesis, if accepted, to be available online in the University’s Open Access repository and for inter-library loans after expiry of a bar on access previously approved by the Academic Standards & Quality Committee. Signed ………………………………………… (candidate) Date …………………. Abstract While the number of 3D geo-spatial digital models of buildings with cultural heritage in- terest is burgeoning, most lack semantic annotation that could be used to inform users of mobile and desktop applications about the architectural features and origins of the buildings. Additionally, while automated reconstruction of 3D building models is an active research area, the labelling of architectural features (objects) is comparatively less well researched, while distinguishing between different architectural styles is less well re- searched still. Meanwhile, the successful automatic identification of architectural objects, typified by a comparatively less symmetrical or less regular distribution of objects on façades, particularly on older buildings, has so far eluded researchers. This research has addressed these issues by automating the semantic and geometric enrichment of existing 3D building models by using Histogram of Oriented Gradients (HOG)-based template matching. The methods are applied to the texture maps of 3D building models of 20th century styles, of Georgian-Regency (1715-1830) style and of the Norman (1066 to late 12th century) style, where the amalgam of styles present on build- ings of the latter style necessitates detection of styles of the Gothic tradition (late 12th century to present day). The most successful results were obtained when applying a set of heuristics including the use of real world dimensions, while a Support Vector Machine (SVM)-based machine learning approach was found effective in obviating the need for thresholds on match- scores when making detection decisions. i Dedication Dedicated to the memory of my sister, Emma, to my partner Siobhan and to my parents Kay and Roger. You never lost faith, despite the ups and downs. ii Acknowledgements Huge thanks must go to my wonderful supervisors Christopher Jones and Paul Rosin. I have valued enormously your wealth of knowledge, experience and patience, plus your ability to drill into the detail while also setting things in a broader context. You kept en- couraging me and pushing me, and I can’t thank you enough. Big thanks also to Isabel Sargent, my Ordnance Survey, Great Britain supervisor. You’ve been a great support, and I’ve really enjoyed the time at headquarters in Southampton. This work was jointly funded by the Engineering and Physical Sciences Research Coun- cil (EPSRC) and the Ordnance Survey, Great Britain, under an EPSRC Industrial Coop- erative Awards in Science and Technology (iCASE) award (1407944). Special thanks go to the following individuals for their assistance: David Holland, Jon Horgan and Debbie Wilson at Ordnance Survey; Yinda Zhang at Princeton, first author on the HOG-based template-matching paper used in this work (Zhang et al., 2013b); Olivier Teboul, creator of the ECP Facades Database (Teboul, 2010); Stefan Buss at 3DIS, the producer of the Trimble SketchUp CityEditor plug-in; Catherine Bankhurst and Charles O’Brien, part of the team at Yale University Press, the producer of the Pevsner architectural guides; Ne- ville Mcauley-Churchill at extraordinarybookofdoors.com; Neil Guiden at Historic Eng- land; Jackie Chadwick at the National Museum Wales; Susan Fielding at the Royal Com- mission on Ancient and Historical Monuments of Wales; Kathryn Betts at Meldreth Local History Group; and Yukun Lai and Oriel Prizeman at Cardiff University. Finally, thank you to my PhD and research colleagues over the years, for your support, especially Kelvin Wong at University College London. iii Quote “Things are not always what they seem; the first appearance deceives many; the intelligence of a few perceives what has been carefully hidden.” Plato in Phraedus c.370 BC iv Contents Abstract ……...………………………………………………………………………………….i Dedication …..…………………………………………………………………………………ii Acknowledgements ................................................................................................... iii Quote …………………………………………………………………………………………..iv 1 Introduction ………………………………..………………………………………………..1 1.1 Motivation ....................................................................................................... 1 1.2 Use Cases for 3D Building Models ................................................................. 3 1.2.1 3D Building Models in Cultural Heritage, BIM & HBIM ............................. 4 1.2.2 3D Building Models for 3D Cadastre ........................................................ 6 1.2.3 National Mapping Agencies & 3D Building Models .................................. 7 1.2.4 Other Use Cases for 3D Building Models including Building Age ............. 7 1.3 Objectives & Research Question .................................................................. 10 1.4 Approach Summary ...................................................................................... 11 1.5 Challenges ................................................................................................... 12 1.6 Main Contributions ........................................................................................ 13 1.7 List of Relevant Publications ......................................................................... 14 1.8 Thesis Outline............................................................................................... 15 1.9 Considerations.............................................................................................. 16 1.9.1 Interdisciplinary Nature .......................................................................... 16 1.9.2 Architectural Style Focus ....................................................................... 16 1.9.3 Development Framework ....................................................................... 16 1.9.4 Data Referencing ................................................................................... 17 2 Background ………………………………………………………………………………..18 v Contents vi 2.1 Introduction ................................................................................................... 18 2.2 3D City Models & 3D Building Models Definition ........................................... 19 2.3 3D Building Models & Semantic Information ................................................. 21 2.3.1 Semantic Information Models ................................................................. 21 2.3.2 CityGML Semantic & Geometric Representation ................................... 23 2.3.3 CityGML Conversion, Quality, Accuracy & Errors .................................. 26 2.4 Architectural Style ......................................................................................... 28 2.4.1 Pre-Gothic Styles & Norman (1066-late C12) ........................................ 32 2.4.2 Gothic Tradition (late C12-present) ........................................................ 36 2.4.3 Classical Tradition (early C16-present) including Georgian-Regency (1715-1830) ......................................................................................................... 37 2.4.4 Modernism ‘Tradition’ (1925-present) & Neo-vernacular ........................ 41 2.5 Reconstruction Techniques........................................................................... 44 2.5.1 Point Clouds & Meshes .......................................................................... 45 2.5.2 3D City Models ...................................................................................... 45 2.6 Computer Vision ........................................................................................... 47 2.6.1 Background & Challenges ..................................................................... 47 2.6.2 Computer Vision Methods .....................................................................