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A new architecture for statistical classification of hand-printed characters is presented. It is based on standard preprocessing and three feature types, containing geometrical information on the position of the pixels, on the contour orientation and on the bending points, respectively. Two feature vectors at a time are used as inputs to a multi-layer perceptron-based classifier, giving rise to three simple classifiers operating in parallel. The outputs of the three different classifiers are mixed by a final supervisor realized by a perceptron layer. The overall network has been trained using digits, upper and lower case letters of the NIST Special Database 3. Classification results of the NIST Test Data 1 are provided. The system has an error rate of 2.59% on the digits of NIST Test Data 1 at zero rejection rate, while it has 2.99 and 11.00% error rate on the upper and lower case letters, respectively.

A new statistical classifier for handwritten character recognition is presented. After a standard preprocessing phase for image binarization and normalization, a distance transform is applied to the normalized image, converting a black and white (B/W) into a gray scale picture. The latter is used as feature space for a k -Nearest-Neighbor classifier, based on a dissimilarity measure which generalizes the use of the distance transform itself. The classifier has been implemented on a massively-parallel processor, Connection Machine CM-2. Classification results of digits extracted from the U.S. Post Office ZIP code database and the upper-case letters of the NIST Test Data 1 are provided. The system has an accuracy of 96.73% on the digits and 94.51% on the upper-case letters when no rejection is allowed and an accuracy of 98.96%, on the digits and 98.72% on the upper-case letters at 1% error rate.

Electromagnetic interference may cause failures in operational amplifiers. The probability of these failures can be reduced by properly designing the opamp, once the failure mechanism has been discovered. In this paper the design of some integrated BiCMOS operational amplifiers with a very low-probability of electromagnetic interference (EMI) induced failures is reported. In particular, it is shown that opamps exhibiting good general performances as well as low EMI-susceptibility can be obtained only if their response to a large square-wave input signal is symmetric and the influence of some parasitic capacitances in the input stage is compensated. Following these guide-lines, we found possible to design BiCMOS opamp structures exhibiting EMI susceptibility of only a few mV up to several hundred MHz when they are driven with an interfering input signal of some volts.