Explicit inversion: an approach to image analysis

Image analysis can be expressed as an inverse problem. Given an image, whic h is the output of some complicated and possibly unknown function, our goal is to estimate the parameters of that function. Formally, at least, the so lution to the problem can be found by inverting the function which produced the image. In practice, this inversion requires two major elements; a feat ure extractor and a parameter estimator. While: there has been much researc h into these two elements, they are generally designed separately from one another. In this paper we introduce an approach to image analysis founded o n the belief that these two elements should be designed as a pair. We label our approach 'explicit inversion', because it allows us to replace the pro blem of implicitly inverting an unknown, possibly high-dimensional function , with that of explicitly inverting a known, low-dimensional function. As a result we achieve major time reductions over the standard approaches while achieving comparable accuracy. (C) 1999 Pattern Recognition Society. Publi shed by Elsevier Science Ltd. All rights reserved.