Vector zone plates as test patterns for linear vector filters

Zone plate test images have been used in image processing and television for some time. In this paper the concept is generalized to a vector zone plate, which proves to be a useful test pattern for linear vector filters, in this case colour image filters. The vector zone plate introduced in this paper consists of a radial frequency sweep oscillating between opponent colours. The direction of the opponent colour vectors varies around the image, so that all colours within a plane in colour space are contained within the pattern. Using one of the few examples of a linear vector filter published so far, the paper shows how different vector zone plate patterns may be used to reveal the frequency response of a filter in different directions in colour space.