时间：2015年9月22日（星期二）上午9:00

地点：东院7D-101

主讲人：Prof David Towers, Dr Catherine Towers

内容提要：

 

Light has unique properties that make it ideal as a modality for instrumentation – photons have no mass so do not alter the system under study and just as we can capture a 3D scene in a photograph there is the potential for massively parallel sensors by exploiting the matrix of pixels on solid state cameras.  At the same time it is important to recognise that developing a novel instrument is not an end in itself, but a capability to be passed on to an end user or applied to a suitably challenging problem in order to better understand a real system or develop new and improved products.

 

In this talk the group’s work in 3D measurement will be charted together with the applications that have been tackled along the way.  Our work in fluid mechanics has centred on particle scattering based methods and recording either pairs of images or a temporal image sequence such that velocity vector fields of the flow can be determined (particle image velocimetry, PIV).  A particular challenge has been to adequately describe turbulent flows in which both coherent structures and stochastic turbulence are evident – necessitating a description beyond that of conventional turbulence flow.  The optimisation of automotive combustion is used as a representative system.

 

We have also developed techniques for full field 3D metrology based on fringe projection – a triangulation approach.  In this case the instrumentation needs to solve the problem of uniquely identifying the order of each interferometric fringe across a scene.  Robust solutions are necessary for routine application and optimal solutions can be obtained using multiple projected fringe wavelengths setup as geometric number sequences.  Higher dynamic range requirements exist in single point ranging sensors necessitating the exploitation of rational numbers.

 

These themes come together in the measurement of mosquito flight in sub-Saharan dwellings where the flight behaviour of mosquitoes attacking a human baited bednet needs to be quantified in order to determine the effects of insecticide treatments and design improved barriers to malaria transmission.  In this case the mosquitoes are analogous to the tracer particles used in flow velocimetry.  Whilst 2D imaging techniques have generated over 50 TerraBytes of field data from which new understanding and new bednet designs have been generated, the 3D behaviour of mosquitoes is needed to continuously map their behaviour.  Triangulation based approaches compatible with the environment of sub-Saharan dwellings will be described and initial data will be shown.  

主讲人简介：
 

David Towers教授简介

David Towers是英国华威大学（University of Warwick）工程学院终身教授，机械和过程工程学科带头人。David Towers于1991年在华威大学获得光学工程博士学位。受皇家学会博士后奖学金资助，1991-1992年在瑞士苏黎世联邦理工学院做研究；1992-2000 宝马公司应用光学实验室、Gaydon测试中心做项目负责人、经理；2000-2005英国赫瑞瓦特大学(Heriot-Watt University),beat365副教授（Reader）；2006-2013英国利兹大学beat365教授；2014-至今，英国华威大学（University of Warwick）工程学院终身教授。

David Towers的主要研究方向是光学传感和检测技术及其在工程、工业、生物科学和临床实践上的应用。他已在Scientific Report, Optical Letter，Optical Express，Applied Optics，Measurement Science and Technology，Review Science Instruments，Experiment in Fluids，etc.上发表了50多篇论文；在系列的国际会议上发表了80多篇论文；多次在大型国际会议作主题邀请报告和分会场邀请报告。David Towers已从EPSRC、Scottish Enterprise和工业界等获得8M多英镑的资助。

Catherine Towers高级研究员简介

Catherine Towers是英国华威大学（University of Warwick）工程学院高级研究员（Principal Research Fellow），国际光学期刊Applied Optics的编委，英国EPSRC的Advanced Fellowship。她于1994年在华威大学获得工程博士学位。2006年获得EPSRC的Advanced Fellowship（全英国每年仅10名）50余万英镑资助，在利兹大学进行长距离高精度测量及物体三维形貌和彩色纹理方面的研究工作。2014年受聘英国华威大学的高级研究员。

Catherine Towers的主要研究方向是光学检测技术及其在工程、工业、生物科学和临床实践上的应用。她已在Scientific Report, Optical Letter，Optical Express，Applied Optics，Measurement Science and Technology，Review Science Instruments，Experiment in Fluids，etc.上发表了40多篇论文；在系列的国际会议上发表了40多篇论文；多次在大型国际会议作主题邀请报告和分会场邀请报告。多次做著名国际系列会议SPIE conference series on Interferometry: Techniques and Analysis的主席和共同主席。