Challenges in using GPUs for the real-time reconstruction of digital hologram images

This is the pre-print version of the final published paper that is available from the link below.In-line holography has recently made the transition from silver-halide based recording media, with laser reconstruction, to recording with large-area pixel detectors and computer-based reconstruction. This form of holographic imaging is an established technique for the study of fine particulates, such as cloud or fuel droplets, marine plankton and alluvial sediments, and enables a true 3D object field to be recorded at high resolution over a considerable depth. The move to digital holography promises rapid, if not instantaneous, feedback as it avoids the need for the time-consuming chemical development of plates or film film and a dedicated replay system, but with the growing use of video-rate holographic recording, and the desire to reconstruct fully every frame, the computational challenge becomes considerable. To replay a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical hologram of ~100 μm particles over a depth of a few hundred millimetres will require O(10^3) 2D FFT operations to be performed on a hologram of typically a few million pixels. In this paper we discuss the technical challenges in converting our existing reconstruction code to make efficient use of NVIDIA CUDA-based GPU cards and show how near real-time video slice reconstruction can be obtained with holograms as large as 4096 by 4096 pixels. Our performance to date for a number of different NVIDIA GPU running under both Linux and Microsoft Windows is presented. The recent availability of GPU on portable computers is discussed and a new code for interactive replay of digital holograms is presented

POMPOMs: Cost-efficient polarity sensors for the MICE muon beamline

Copyright @ 2011 The AuthorsThe cooling effect in MICE (Muon Ionisation Cooling Experiment) will be studied with both positive and negative muons, reversing the electrical input to the magnets by physically swapping over the power leads. Ensuring the actual operating polarity of the beamline is correctly recorded is a manual step and at risk of error or omission. We have deployed a simple system for monitoring the operating polarity of the two bending magnets by placing in each dipole bore a Honeywell LOHET-II Hall-effect sensor that operates past saturation at nominal field strengths, and thus return one of two well-defined voltages corresponding to the two possible polarities of the magnet. The environment in the experimental hall is monitored by an AKCP securityProbe 5E system integrated into our EPICS-based controls and monitoring system. We read out the beamline polarity sensors using a voltmeter module, and translate the output voltage into a polarity (or alarm) state within EPICS whence it can be accessed by the operators and stored in the output datastream. Initial tests of the LOHET-II sensors indicate they will still be able to indicate beamline polarity after radiation doses of 900 Gy (Co60)

GRID

Presentation at 39th MICE Collaboration Meeting (CM39), 25th-28th June 2014. https://indico.cern.ch/event/321200/timetable/ (Slides titled "Grid Status", updated 27th June 2014

Data Extraction for Underwater Particle Holography

Presentation to ECE dept

GRID Status

Presentation at 40th MICE Collaboration Meeting (CM40), 26th-29th October 2014. https://indico.cern.ch/event/331481/timetable/ Slides titled "Grid Status"

GRID Status

Presentation at 44th MICE Collaboration Meeting (CM44), 30th March - 1st April 2016. https://indico.cern.ch/event/485764/timetable/ (Slides titled "Grid Status"

Status and Plans for Applications Monitoring

Talk at the UK CMS Collaboration Meeting 2004, University of Bristol, Bristol, UK; 1st-2nd July 200

Using the EVO Videoconferencing Workstation

User instructions for the EVO Videoconferencing Workstation in the BITlab Boardroo

Underwater Particle Holography and Grid Middleware

Presentation to ECE dept

Use of a hardware token for Grid authentication by the MICE data distribution framework

The international Muon Ionization Cooling Experiment (MICE) is designed to demonstrate the principle of muon ionisation cooling for the first time. Data distribution and archiving, batch reprocessing, and simulation are all carried out using the EGI Grid infrastructure, in particular the facilities provided by GridPP in the UK. To prevent interference - especially accidental data deletion - these activities are separated by different VOMS roles. Data acquisition, in particular, can involve 24/7 operation for a number of weeks and so for moving the data out of the MICE Local Control Room at the experiment a valid, VOMS-enabled, Grid proxy must be made available continuously over that time. The MICE "Data Mover" agent is now using a robot certificate stored on a hardware token (Feitian ePass2003) from which a cron job generates a “plain” proxy to which the VOMS authorisation extensions are added in a separate transaction. A valid short-lifetime proxy is thus continuously available to the Data Mover process. The Feitian ePass2003 was chosen because it was both significantly cheaper and easier to actually purchase than the token commonly referred to in the community at that time; however there was no software support for the hardware. This paper describes the software packages, process and commands used to deploy the token into production.Department of Energy and National Science Foundation (USA); Instituto Nazionale di Fisica Nucleare (Italy); Science and Technology Facilities Council (UK); European Commission Framework Programme 7; Japan Society for the Promotion of Science; Swiss National Science Foundatio