Speaker
Prof.
Peter R Hobson
(Brunel University)
Description
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 used for small 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. To reconstruct a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical hologram of ~100 micrometre particles over a depth of a few hundred millimetres will require O(1000) 2D FFT operations to be performed on an hologram of typically a few million pixels. With the growing use of video-rate recording and the desire to reconstruct fully every frame the computational challenge becomes considerable. In previous work (http://bura.brunel.ac.uk/handle/2438/2823) we have reported on our experiences with reconstruction on a computational grid. In this paper we discuss the technical challenges in converting our reconstruction code to make efficient use of the NVIDIA CUDA based GPU cards and show how near real-time video slice reconstruction can be obtained with holograms as large as 4K by 4K pixels. We also discuss the issues surrounding the reconstruction of holograms which are larger than 50% of the GPU memory where a different approach to reconstruction will be needed. Finally we consider the implications for grid and cloud computing, and the extent to which GPU can replace these approaches, when the important step of locating focussed objects within a reconstructed volume is included.
Author
Dr
Ivan D Reid
(Brunel University)
Co-authors
Dr
Jindrich Nebrensky
(Brunel University)
Prof.
Peter R Hobson
(Brunel University)
