Publications

PhD thesis

PhD project with Applied Optics Group in the Department of Physics of the University of Edinburgh entitled Optical Correlation using Pixellated Spatial Light Modulators.

The title refers to pattern recognition operations on 2-D images, carried out optically using reconfigurable liquid-crystal based optoelectronic devices. This involved building the (custom) devices and their electronic drive circuitry, carrying out computational simulations and calculating the analytic solutions of optical transfer functions. The project introduces and implements an idea which allows troublesome aliasing in the output of the optical processor to be reduced, or at best, eliminated, by means of randomly displacing the pixel centres according to a carefully chosen statistical distribution. The degree of PhD was awarded in November 1993.

Papers

Investigation of suppression of sidelobes by simple displacement of clustered groups of regularly spaced antennas, S.Heddle, Atacama Large Millimeter Array Memo Series number 353, March 2001.

ALMA array simulations comparing ring and spiral configurations using Classic AIPS, S.Heddle, presented to ALMA Configuration Working Group Principal Design Review meeting, Grenoble, Feb 2001.

Automation of imaging simulations for ALMA using Classic AIPS, S.Heddle and A.S.Webster, Atacama Large Millimeter Array Memo Series number 290, February 2000.

Evaluation of prompting system using interval cancers, S.Heddle, A.C.Hume and A.E.Kirkpatrick, presented at the 4th International Workshop on Digital Mammography, Nijmegen, June 1998.

Performance improvement in optical target recognition, Mark L.Begbie, Steven Heddle, Ian Underwood and David G.Vass, presented at Photonics West:Electronic Imaging Science and Transducers in San Jose, Feb 1997.

Optical interconnect using pixellated spatial light modulators, J.Gourlay, S.Heddle, A.O'Hara, S.Samus and D.G.Vass, presented at OC94, The International Conference on Optical Computing, at Heriot-Watt University, August 1994. Subsequently published in Inst. Phys. Conf. Ser. 139:Part II, pp207-210 (1995).

Board Counting Apparatus, Steven Balfour Heddle for International Metrology Systems Ltd., UK Patent App. 9521280.9, October 1995.

Liquid crystal over silicon spatial light modulators and coherent image amplification, S.Heddle, presented at the Rank Prize Funds Mini-Symposium on Coherent Image Amplification, Grasmere, 20th-23rd June 1994.

Reduction and removal of replication in an optical processor by randomisation of pixel positions in the Fourier plane filter, S.Heddle and R.M.Sillitto, Journal of Modern Optics 40 (2), pp219-313 (1993).

Specification of an optical correlator for road sign recognition, S.Heddle, W.J.Hossack and D.G.Vass, presented by S.Heddle at Optical Society of America Annual Meeting in Toronto on 8th October 1993. Summarised in OSA Annual Meeting Technical Digest 1993, 16, p234 (1993).

Reduction of aliasing in correlation using a pixellated spatial light modulator, S.Heddle, D.G.Vass and R.M.Sillitto, presented by S.Heddle at SPIE's International Symposium on Optical Applied Science & Engineering in San Diego on 20th July 1992. Published in Proceedings of the SPIE 1772, pp116-127 (1992).