Between 1993 - 1996 I conducted research for a PhD with Dr. Steve Sangwine as my supervisor on Colour object recognition using a complex colour representation and the frequency domain (PDF format), 205pp.

Colour pixels are described as complex values and used as input to a 2D FFT. The result of the transform is used together with additional processing to be able to recognise objects in an image and also discriminate different coloured objects of the same shape.

The processing also overcomes problems associated with translation, rotation and scaling.

The abstract to the thesis gives an overview.