2007.7: Stochastic Resonance in Vision: Models and Data
2007.7: Carole Tham (2006) Stochastic Resonance in Vision: Models and Data. PhD thesis, The University of Manchester.
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Stochastic resonance (SR) is a phenomenon whereby small amounts of additive noise can greatly enhance the performance of a non-linear signal processing system. It is well known that many sensory systems are non-linear in nature and the phenomenon of SR has been widely studied in them. Perhaps one underexplored area of research is the visual system, in particular the retina and this pro ject aims to explore to what extent SR is or could be utilised in the retina. The thesis is organised as follows: In chapter one I look at the historical development of SR from its conception as an explanation of the periodic occurrence of ice ages to applications in sensory systems. The structure of the retina is explored in chapter two and I explain why SR might be expected to occur in visual systems. The mathematics of the problem is detailed in chapter three, showing why SR arises in systems containing a threshold type non-linearity. The phenomenon is extensively studied experimentally in chapter four, with many different stimuli being tested. These are broadly organised into two types of task, detection and discrimination, with each stimulus carefully designed to probe a different aspect of the phenomenon. In the final chapter overall conclusions are drawn, the scope for future work is explored, including the description of a retina model and the possibilities for practical applications are raised.
The thesis contains novel receiver operating characteristic (ROC) curves, used to demonstrate that SR can occur in systems containing a threshold type non-linearity. I go on to show that noise can be used to enhance the perceptibility of some signals. However, this enhanced perception is shown to be limited to low level visual tasks.
|Item Type:||Thesis (PhD)|
Dr. Tham worked with Dr. M. Muldoon and Prof. R.V. Abadi.
|Uncontrolled Keywords:||Stochastic resonance, noise|
|Subjects:||MSC 2000 > 92 Biology and other natural sciences|
PACS 2003 > 87 Biological and medical physics
|Deposited By:||Dr Mark Muldoon|
|Deposited On:||12 January 2007|