A circuit for extracting a connected component feature from an input image includes an input stage, a counting stage, a bit-preparing stage, and a bit-output stage. The input stage receives a bit pattern and detects a connected component in the bit pattern. The counting stage counts the number of connected components detected in the input stage and generates a current representing that number. The bit-preparing stage generates more than one current as a basis for information including more than one bit, based on the current generated in the counting stage, so that the information uniquely represents the number of connected components. The bit-output stage converts the currents generated in the bit-preparing stage into a digital output corresponding to the information.
Methods and systems of the present invention may be used to recognize digital image data arranged in rows and columns. Exemplary embodiments may include a feature extractor for extracting feature information from data representing the rows and columns of the digital image data, a feature compressor for compressing the extracted feature information, and a neural network for classifying the digital image data from the compressed, extracted feature information.