Bounded-depth threshold circuits for computer-assisted CT image classification

  • Authors:
  • A. Albrecht;E. Hein;K. Steinhöfel;M. Taupitz;C. K. Wong

  • Affiliations:
  • Department of Computer Science and Engineering, CUHK, Shatin, N.T., Hong Kong, Hong Kong;Faculty of Medicine, Institute of Radiology, Humboldt University, 10117 Berlin, Germany;GMD-National Research Center for IT, Kekuléstraíe 7, 12489 Berlin, Germany;Faculty of Medicine, Institute of Radiology, Humboldt University, 10117 Berlin, Germany;Department of Computer Science and Engineering, CUHK, Shatin, N.T., Hong Kong, Hong Kong

  • Venue:
  • Artificial Intelligence in Medicine
  • Year:
  • 2002

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Abstract

We present a stochastic algorithm that computes threshold circuits designed to discriminate between two classes of computed tomography (CT) images. The algorithm employs a partition of training examples into several classes according to the average grey scale value of images. For each class, a sub-circuit is computed, where the first layer of the sub-circuit is calculated by a new combination of the Perceptron algorithm with a special type of simulated annealing. The algorithm is evaluated for the case of liver tissue classification. A depth-five threshold circuit (with pre-processing: depth-seven) is calculated from 400 positive (abnormal findings) and 400 negative (normal liver tissue) examples. The examples are of size n=14,161 (119 x119) with an 8 bit grey scale. On test sets of 100 positive and 100 negative examples (all different from the learning set) we obtain a correct classification close to 99%. The total sequential run-time to compute a depth-five circuit is about 75h up to 230h on a SUN Ultra 5/360 workstation, depending on the width of the threshold circuit at depth-three. In our computational experiments, the depth-five circuits were calculated from three simultaneous runs for depth-four circuits. The classification of a single image is performed within a few seconds.