Real-time ordinal-value filters utilizing complete intra-data comparisons

Abstract

Operating at real-time data rates, the disclosed hardware apparatus determine which one of a set of R input data signals is the Mth-largest. Mutual comparisons between the data values themselves provides the basis for the mechanized determination schemes. After every data signal is pair-wise compared (112-167) with every other data signal, each subset of results (C12-C17, C12-C27, C13-C37, C14-C47, C15-C57, C16-C67), consistng of the outcome of the comparisons between a given data signal and all other data signals, is tested (210-260) to determine whether the results indicate that (M-1) of the other data signals are greater than the given signal. That data signal whose result set satisfies this (M-1) condition is the Mth-largest and is used (270, 280) as the network output (285). For data that is serially-presented (490,400) a network simplification makes set-testing possible after only one data value, that most-recently-presented, is compared (412-417) to all other (R-1) signals of the set. The simplification entails reducing the number of comparators utilized, while employing storage elements (512-567) to preserve for set-testing purposes the appropriate ones of the results of comparisons made prior to the presentation of the most-recent serial data element. When the number R of inputs is odd and M is made equal to (R+1)/2, the networks become real-time median filters.