1. A system for computing class identifiers for three-dimensional pixel data comprising: a plurality of class identifying processors, each class identifying processor having a plurality of inputs for at least one pixel value and a plurality of class identifiers for pixel values neighboring the at least one pixel value and each class identifying processor being configured to generate a class identifier for the at least one pixel value input with reference to the class identifiers for the neighboring pixel values; and a data grouper operatively connected to a first memory and to the plurality of inputs for each class identifying processor in the plurality of class identifying processors, the data grouper being configured to retrieve a plurality of pixel values from the first memory, a plurality of class identifiers for pixel values neighboring each retrieved pixel value from the first memory, and to provide the at least one pixel value and the plurality of class identifiers for the pixel values neighboring the at least one pixel value for each class identifying processor in the plurality of class identifying processors.