Classifier Adaptation with Non-representative Training Data

  • Sriharsha Veeramachaneni
  • George Nagy
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2423)


We propose an adaptive methodology to tune the decision boundaries of a classifier trained on non-representative data to the statistics of the test data to improve accuracy. Specifically, for machine printed and handprinted digit recognition we demonstrate that adapting the class means alone can provide considerable gains in recognition. On machineprinted digits we adapt to the typeface, on hand-print to the writer. We recognize the digits with a Gaussian quadratic classifier when the style of the test set is represented by a subset of the training set, and also when it is not represented in the training set. We compare unsupervised adaptation and style-constrained classification on isogenous test sets of five machine-printed and two hand-printed NIST data sets. Both estimating mean and imposing style constraints reduce the error-rate in almost every case, and neither ever results in signi.cant loss. They are comparable under the first scenario (specialization), but adaptation is better under the second (new style). Adaptation is bene.cial when the test is large enough (even if only ten samples of each class by one writer in a 100- dimensional feature space), but style conscious classification is the only option with fields of only two or three digits.


Error Count Maximum Likelihood Linear Regression Handwritten Numeral Hierarchical Bayesian Approach Adaptive Methodology 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Sriharsha Veeramachaneni
    • 1
  • George Nagy
    • 1
  1. 1.Rensselaer Polytechnic InstituteTroyUSA

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