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Abstract

The main concern of this research is an investigation of the perception of colour from achromatic flicker, particularly the colours observed on many black and white rotating patterned discs. The first chapter is an attempt to review, in a critical manner, the literature available on this subject and to discuss general and relevant topics on human colour vision. The second chapter deals with the apparatus developed. Included in this chapter is a description of a white light modulator, which was used in most of the experimentation. It was found, using two of these modulators, that the colour effects observed on many rotating patterned discs could be reproduced in a static stimulus display. Necessary for the evokation of the colours, was that the visual field should comprise two intermittent regions; one region (defined as the target) in which the colours were produced, and the other defined by the areas surrounding the target. Initial experiments employed a grating type of stimulus (see figure 36, Chapter 3) and the colours induced in the stimulus were measured with a binocular matching technique. The second experiment shows that the full gamut of subjective colours observed as rotating patterned discs cannot be reproduced in a single intermittent light by a manipulation of flicker waveform. One of the commonly held theories of the subjective colours is suggested as untenable from this result. The general conclusion from most of the experimental work is that colour coded ganglion cells in the retina, whose receptive fields have a centre-surround spatial configuration, are the most likely candidates for the visual mechanisms responsible for the subjective colours. A theory is given which suggests possible ways in which the dynamic behaviour of such cells can account for the subjective colours. Data are also obtained which possibly reflect the sizes of some colour coded ganglion cell receptive fields. Finally, an electrophysiological experiment is performed to find possible reflections in human electro-retinographic and evoked potential data, of subjective colour inducing mechanisms. The results of this experiment are, on the whole, rather inconclusive.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QP Physiology R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry R Medicine > RE Ophthalmology
Departments:	School of Health & Medical Sciences > Department of Optometry & Visual Science Doctoral Theses

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