| 摘要 |
<p>An apparatus for determining from a set of data describing A samples each in terms of B parameters those parameters which are important in distinguishing one sample from another. The apparatus comprises means for performing a first expansion to determine the pigenvectors and eigenvalues of a covariance or related matrix D, where D is as shown in formula (I) or an approximation thereto, and C is a parameter vector or matrix having B elements corresponding to the B parameters of one of the samples. The parameter corresponding to the largest value (by magnitude) in the eigenvector of greatest eigenvalue is selected to constitute a first selected parameter. The parameter other than the first selected parameter corresponding to the largest value by magnitude in the eigenvector having a second highest eigenvalue is then selected to constitute a second selected parameter, and further parameters other than those previously selected corresponding to the largest magnitude values in the eigenvectors having the third, fourth and consequent highest eigenvalues are selected to constitute the third, fourth and subsequent selected parameters until the eigenvalues of the remaining eigenvectors are too small to contain the further significant data. The selected parameters describe substantially all the intrinsic variations in the data set and therefore describe substantially all the features of the samples which are significant in distinguishing one sample from another.</p> |
