Abstract: Operating at real-time data rates, the disclosed hardware network generates a signal which closely approximates the Mth-largest of a set of R input data signals. The operational basis of this network is a comparison (121-127) between the input data (101-107) and a monotonically-scanning reference function (110). At that point (140, 150, 160) when the lower (R-M+1) of the inputs have been equaled by an increasing reference, the reference has become the same as the Mth-largest and is used (119b, 165, 170, 175) as the filter output. Analogous operation is achieved with a decreasing reference.When the number R of inputs is odd and M is made equal to ((R+1)/2), the network becomes a real-time median filter.

Abstract: A hardware logic network, operating at real-time data rates, generates a signal which matches the Mth-largest signal of an input data set. To accomplish this signal-matching, the network utilizes an iterative series of value adjustments which cause an intermediate working quantity to converge to a number whose rank in comparison to the input set is the same as that of the true Mth-largest. When test comparisons indicate that the intermediate value's relative rank is too low, the value-adjustment is upward. The adjustment is downward otherwise. Operating upon input data whose range of possible values is limited to a predetermined interval, the system takes as its initial working quantity the midpoint of this interval. The magnitude of the first adjustment is one-half of the remaining interval on either side of the initial approximation. Subsequent magnitude adjustments are in turn one-half of the preceeding half-remaining-interval magnitude.

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.

Abstract: Operating at real-time data rates, hardware logic networks (FIGS. 3-6) receive onto a data-channel array (390 in FIG. 3) a set of unordered input data values and iteratively pair-wise transpose the set members until their positional order on the array coincides with the order the members would assume if their magnitudes were arranged according to sequential ordinal rank. Pair-wise comparisons between the data values themselves provide the basis for the mechanized pair-wise transposition schemes.Within each network, a key building block for performing both the pair comparisons and member transpositions is a Number Pair Orderer (NPO) (FIG. 2). Each NPO compares (210) two data elements and passes the smaller to one of its outputs (240), while passing the larger to the other of its outputs (260). Individual NPO's are arranged into two groups (311-315 and 321-325), each of which operates iteratively upon pairs of substantially all of the data values.

Abstract: A scene tracker for use with imaging or quasi-imaging sensors such as TV cameras, FLIRS, millimeter-wave scanners, or the like is disclosed. Specifically, the invention is concerned with a form of correlation tracking. At the start of a track mode, part or parts of a scene are stored in a memory. Every subsequent video scan is then compared with the scene or parts of the scene stored in memory to find the "best match" between live data and stored data. This process generates signal output proportional to horizontal and/or vertical translations of the scene. Besides pure translation, the disclosed scene tracker is capable of tracking an original aim point in the presence of scene rotation, scene growth (zooming), scene reduction (dezooming), distortion, and/or partial scene obscuration.

Abstract: A television camera is trained on a target to produce a video image thereof. The video signals are converted to unipolar form such that black to white and white to black contrast produces the same polarity video signals and these signals appropriately filtered so that only the desired target signals remain. A tracking gate is generated which automatically accommodates to the size of the selected target and forms an optical window which surrounds the target on a viewing screen. In an acquisition mode of operation, the operator brings the target so that it lies within the window at which time he initiates a "track" mode of operation whereupon error signals are generated as the target moves out of the window, these error signals being utilized in a servo system to slew the camera such as to maintain "lock-on".