Abstract: Coin validation can be advantageously improved by transforming measured data values associated with coin characteristics from a first geometric space to a second geometric space, in which the transformed values in the second geometric space are preferably better adapted for discrimination between different coin denominations than the corresponding values in the first geometric space. Preferably, principal component analysis is used to identify principal components that can be used as dimensions of the second geometric space, so that measured data values in the second geometric space are less correlated than in the first geometric space.

Abstract: Apparatus for obtaining certain characteristics of an article (60, 62), the apparatus including an electromagnet inductor (10, 30) with a first end (20, 54) and a second end (20, 54) with an air gap (24, 58) therebetween, there being at least one arm (12, 32, 34) joining the first end (20) and the second end (20) having electrical windings (14, 52) to generate a magnetic flux in the air gap (24, 58), the arm (12, 32, 34) being a fixed return path for the magnetic flux.

Abstract: A method of categorizing coins/tokens by energizing detect coils with a single pulse detecting the back EMF curve of the decaying pulse information, analyzing the unmodified back EMF curve to extract therefrom a number of variables and processing those variables to provide values proportional to the variables, and comparing the values of the coin/token to at least one of a number of reference values to determine into which of a number of predetermined categories the coin/token falls.