Effective Design, Configuration, and Use of Digital CCTV, Which Is Entitled Task Effective CCTV Video in Security (TEC-VIS)
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Effective, Design, Configuration, and Use of Digital CCTV Hina Uttam Keval A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy of University College London Department of Computer Science University College London April 2009 1 I, Hina Uttam Keval, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. _______________________________ Hina Uttam Keval 2 To my parents and sisters. 3 Abstract It is estimated that there are five million CCTV cameras in use today. CCTV is used by a wide range of organisations and for an increasing number of purposes. Despite this, there has been little research to establish whether these systems are fit for purpose. This thesis takes a socio-technical approach to determine whether CCTV is effective, and if not, how it could be made more effective. Human- computer interaction (HCI) knowledge and methods have been applied to improve this understanding and what is needed to make CCTV effective; this was achieved in an extensive field study and two experiments. In Study 1, contextual inquiry was used to identify the security goals, tasks, technology and factors which affected operator performance and the causes at 14 security control rooms. The findings revealed a number of factors which interfered with task performance, such as: poor camera positioning, ineffective workstation setups, difficulty in locating scenes, and the use of low-quality CCTV recordings. The impact of different levels of video quality on identification and detection performance was assessed in two experiments using a task-focused methodology. In Study 2, 80 participants identified 64 face images taken from four spatially compressed video conditions (32, 52, 72, and 92 Kbps). At a bit rate quality of 52 Kbps (MPEG-4), the number of faces correctly identified reached significance. In Study 3, 80 participants each detected 32 events from four frame rate CCTV video conditions (1, 5, 8, and 12 fps). Below 8 frames per second, correct detections and task confidence ratings decreased significantly. These field and empirical research findings are presented in a framework using a typical CCTV deployment scenario, which has been validated through an expert review. The contributions and limitations of this thesis are reviewed, and suggestions for how the framework should be further developed are provided. 4 Acknowledgements The journey one must make to earn a PhD can be very lonely. I am fortunate to have had the support of many people from academia and industry along the way. I am sincerely indebted and thankful to all of them. This work could not have come together without their help. I would like to acknowledge that this PhD research was funded by the European Physical Science Research Council (EPSRC) 2004–2007, grant no. EP1P50064811. I am most grateful to my dedicated supervisors Prof. M. Angela Sasse and Dr Simon Prince. Angela has given me great confidence, encouragement, guidance, and a tremendous amount of support throughout my research studies. I would like to thank my second supervisor, Simon, who kindly gave me advice and constructive comments on the empirical parts of my research. A very big thank you goes to Hendrik Knoche, my official PhD mentor, colleague, and friend. Hendrik provided me with guidance on my video quality experiments and taught me a great deal about video, imaging and data analysis. Thank you to Dimitris Miras who provided feedback on my early experimental ideas and offered his expertise on video quality. I would also like to thank Dr Paul Cairns (formerly of UCLIC and now at York University) who was so willing to offer his time to review my research papers and offer guidance on data analysis for my empirical experiments – even on short notice. I would like to thank Hendrik Knoche and Sven Laqua who helped me program my experiments. I am also very grateful to all of my colleagues in the Department of Computer Science who provided their opinions on my research ideas and gave their time to review papers and drafts: Dr John McCarthy, Dr Jens Reigelsberger, Dr Vinoba Vinayagamoorthy, and Rae Harbird. Special thanks are also due to Jim Aldridge (former senior Home Office video expert, and now consultant at Effective Pictures, Ltd) for providing me with a huge amount of insight and offering his expertise on the technical problems surrounding CCTV. Several other individuals also helped me refine my ideas through discussions, long email queries, and telephone calls: John Wood (CCD Design and Ergonomics), Prof. Alf Linney (UCL), Dr Ian Nimmo (User Centered Design Services, LLC), Dr Martin Maguire (ESRI), Dr Iain Darker (ESRI), and my colleagues at the Home Office Scientific Development Branch (HOSDB): Simon Walker, Neil Cohen, Jay Gatusso, and Dr Ken Brown- Maclennan. Finally, I would like to thank my family, friends and my dear Edward Elton for giving me the strength, encouragement, moral, and financial support throughout – it really went a long way. 5 Contents Abstract.......................................................................................................................................4 Acknowledgements......................................................................................................................5 Contents ......................................................................................................................................6 List of Figures............................................................................................................................11 List of Tables.............................................................................................................................12 Chapter 1...................................................................................................................................13 1.1 Introduction....................................................................................................................13 1.2 Research Problems .........................................................................................................16 1.2.1 Research Problem 1...............................................................................................17 1.2.2 Research Problem 2...............................................................................................17 1.3 Research Scope and Approach ........................................................................................18 1.4 Research Goals...............................................................................................................20 1.4.1 Research Goal 1 ....................................................................................................20 1.4.2 Research Goal 2 ....................................................................................................20 1.4.3 Research Goal 3 ....................................................................................................21 1.5 Thesis Structure..............................................................................................................21 PART 1: Control Room Research...............................................................................................24 Chapter 2...................................................................................................................................25 Previous Control Room Studies..................................................................................................25 2.1 Introduction....................................................................................................................25 2.2 Security Control Room Studies.......................................................................................26 2.3 Non-Security Control Room Studies ...............................................................................27 2.4 Control Room Guidance .................................................................................................33 2.5 Chapter Summary...........................................................................................................34 Chapter 3...................................................................................................................................36 Field Research: Methodology.....................................................................................................36 3.1 Introduction....................................................................................................................36 3.2 Interviews ......................................................................................................................37 3.2.1 Unstructured Interviews.........................................................................................37 3.2.2 Semi-structured and Structured Interviews .............................................................37 3.3 Observations ..................................................................................................................38 3.3.1 Ethnography..........................................................................................................39 3.3.2 Contextual Inquiry.................................................................................................41 3.3.2.1 The Concepts .............................................................................................................41 3.3.2.2 The Process................................................................................................................42