Defining a perceptual space

To examine these two main formulations, and to show demonstrate other possibilities, we shall adopt a general formulation based on perceptual spaces. In this, we first define a perceptual space in which each feature combination lies. This space is defined so that we can use a simple distance metric (e.g. Euclidean) to measure the perceptual distances between feature combinations. Secondly, we define a mapping that specifies where each feature combination lies in this space. 

In 1976, the CIE defined a three-dimensional color space that is perceptually more uniform than the CIE XYZ color space (International Commission on Illumination 1996). The... 

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