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Computational Mathematics and Applications seminar
Date and Time: Thursday February 21st at 2pm
Location: CR21 (R1) @ RAL (with video link to Barkla, A Block @ DL)
Speaker: Professor Martin S. Andersen, Technical University of Denmark
Title: Tomographic imaging with flat-field uncertainty
Classical methods for X-ray computed tomography (CT) are based on the
assumption that the X-ray source intensity is known. In practice, however, the
intensity is measured and hence uncertain. Under normal circumstances, when the
exposure time is sufficiently high, this kind of uncertainty typically has a
negligible effect on the reconstruction quality. However, in time- or
dose-limited applications such as dynamic CT, this uncertainty may cause severe
and systematic artifacts known as ring artifacts.
By modeling the measurement process and by taking
uncertainties into account, it is possible to derive a convex reconstruction
model that leads to improved reconstructions when the signal-to-noise ratio is
low. We discuss some computational challenges associated with the model and
illustrate its merits with some numerical examples based on simulated and real
All welcome. You are also invited to come and join us for lunch in the
Rutherford restaurant beforehand.
Please let me know if you plan to attend so that the relevant security
arrangements can be made. On arrival, visitors should report to the Main
For information about travelling to the Rutherford Appleton Laboratory, please
Parking is available if needed.
If travelling from Oxford
The Science Transit Shuttle runs every 30 minutes from various pickup
points in Oxford (including the Science area) directly to RAL. Details are
The Thames Travel X32 bus travels between Oxford and the Harwell Campus
(~ 60 minute journey, with a bus every hour).
If travelling by Train
The Thames travel X32/32A/X34 buses travel between Didcot Parkway
Station and the Harwell Campus (~ 15 minute journey, with a bus every 15
minutes). Taxis are also available at Didcot Parkway Station.
For further information, contact Tyrone Rees (email@example.com).
+44 (0) 1235 446834