Image usefulness of compressed surveillance footage with different scene contents

Tsifouti, A. 2016. Image usefulness of compressed surveillance footage with different scene contents. PhD thesis University of Westminster Media, Arts and Design

TitleImage usefulness of compressed surveillance footage with different scene contents
TypePhD thesis
AuthorsTsifouti, A.
Abstract

The police use both subjective (i.e. police staff) and automated (e.g. face recognition systems) methods for the completion of visual tasks (e.g person identification). Image quality for police tasks has been defined as the image usefulness, or image suitability of the visual material to satisfy a visual task. It is not necessarily affected by any artefact that may affect the visual image quality (i.e. decrease fidelity), as long as these artefacts do not affect the relevant useful information for the task. The capture of useful information will be affected by the unconstrained conditions commonly encountered by CCTV systems such as variations in illumination and high compression levels. The main aim of this thesis is to investigate aspects of image quality and video compression that may affect the completion of police visual tasks/applications with respect to CCTV imagery. This is accomplished by investigating 3 specific police areas/tasks utilising: 1) the human visual system (HVS) for a face recognition task, 2) automated face recognition systems, and 3) automated human detection systems.

These systems (HVS and automated) were assessed with defined scene content properties, and video compression, i.e. H.264/MPEG-4 AVC. The performance of
imaging systems/processes (e.g. subjective investigations, performance of compression algorithms) are affected by scene content properties. No other investigation has been identified that takes into consideration scene content properties to the
same extend. Results have shown that the HVS is more sensitive to compression effects in comparison to the automated systems. In automated face recognition systems, `mixed lightness' scenes were the most affected and `low lightness' scenes were the least affected by compression. In contrast the HVS for the face recognition task, `low lightness' scenes were the most affected and `medium lightness' scenes the least affected. For the automated human detection systems, `close distance' and `run approach' are some of the most commonly affected scenes. Findings have the potential to broaden the methods used for testing imaging systems for security applications.

Year2016
FileTsifouti_Anastasia_thesis.pdf

Related outputs

Comparative performance between human and automated face recognition systems, using CCTV imagery, different compression levels and scene parameters
Tsifouti, A., Triantaphillidou, S., Larabi M-C, Bilissi, E. and Psarrou, A. 2015. Comparative performance between human and automated face recognition systems, using CCTV imagery, different compression levels and scene parameters . SPIE Electronic Imaging: Image Quality and System Performance XII. San Fransisco, USA Jan 2015 SPIE. doi:10.1117/12.2083325

The effects of scene content parameters, compression, and frame rate on the performance of analytics systems
Tsifouti, A., Triantaphillidou, S., Larabi, M.C., Doré, G, Bilissi, E. and Psarrou, A. 2015. The effects of scene content parameters, compression, and frame rate on the performance of analytics systems. SPIE Elecgtronic Imaging: Image Quality and System Performance XII. San Fransisco, USA Jan 2015 SPIE. doi:10.1117/12.2083426

A case study in identifying acceptable bitrates for human face recognition tasks
Tsifouti, A., Triantaphillidou, S., Larabi, M.C., Bilissi, E. and Psarrou, A. 2015. A case study in identifying acceptable bitrates for human face recognition tasks. Signal Processing: Image Communication . 36, p. 14–28. doi:10.1016/j.image.2015.05.002

Acceptable bit-rates for human face identification from CCTV imagery
Tsifouti, A., Triantaphillidou, S., Bilissi, E. and Larabi, M.C. 2013. Acceptable bit-rates for human face identification from CCTV imagery. in: Burns, P.D. and Triantaphillidou, S. (ed.) Image Quality and System Performance X SPIE.

Permalink - https://westminsterresearch.westminster.ac.uk/item/9x1qv/image-usefulness-of-compressed-surveillance-footage-with-different-scene-contents


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