Imants works in the School of Physics at Monash University as a Senior Lecturer

Imants' research areas of interest are:

• Imants' current research currently concerns discrete projections. These techniques are used, for example, in medical imaging as x-ray computed tomography (CT). Over the last ten years, Imants has adapted the Finite Radon Transform (FRT) to exploit the information held in discrete projections. The FRT is based on square, prime length arrays that permit an exact interconversion of digital images and their discrete projections. Recently completed Monash PhD student, Shekhar Chandra, has developed, amongst many new results, an efficient number-theoretic means for rapid computation of the FRT.
• The FRT projections are close cousins of the Mojette projections developed by Prof. Jean-Pierre Guandeacute;don of the Image and Vision Communication group (IVC) at the Polytech'Nantes in France (see our recent textbook: J-P. Guandeacute;don (Ed.), The Mojette Transform: Theory and Applications, ISTE-Wiley, 2009). Mojette projections provide a very general and flexible representation of digital objects. They have a wide range of uses, ranging from secure data encryption to limited-angle tomographic imaging.
• The collaboration between Monash and Nantes researchers has been active since early 2005, resulting in ongoing student and research staff exchanges. Five internship students from Nantes worked on research projects at Monash in 2010, following two students from 2009. Dr Nicolas Normand, one of the original co-workers with Prof. Guandeacute;don, spent 2009/2010 working at Monash as an ARC International Fellow. Dr Benoit Parrein from Nantes also visited Monash in 2010, aided by a Monash European Hosting Grant.
• A simple, but powerful criterion (formalised by Katz in 1978) determines whether a discrete set of projections can reconstruct an object exactly. Insufficient or missing information gives rise to artefacts or ghost images in the reconstruction. It turns out that these ghosts carry valuable information. The trick is to construct these projection ghosts using the minimum number of points; 2N pixels instead of the usual order 2N pixels required by other methods. These minimal ghosts turn out to have amazing symmetry and very interesting correlation properties. These ghosts can also be used to generate image-anti-image data that has zero-sum projections at N projection angles.