Abstract: Apparatus (100) is provided which is arranged to accept an input data stream. In some embodiments, the apparatus (100) comprises a sampler arranged to sample the input data stream to provide k samples thereof, wherein each of the samples is n bits long and a string selector arranged to select m binary strings n bits long from at least a chosen subset of all random binary strings of a predetermined length. The apparatus (100) may further comprise a logical operator arranged to perform a logical function for each of the k samples with each of the selected binary strings to provide a vector, a memory arranged to store a matrix of the vectors generated from k samples, and an address generator arranged to generate RAM address segments from the matrix. In embodiments, the apparatus (100) may comprise a processor for, for example, pattern matching; feature detection, image recognition.

Abstract: Apparatus (100) is provided which is arranged to accept an input data stream. In some embodiments, the apparatus (100) comprises a sampler arranged to sample the input data stream to provide k samples thereof, wherein each of the samples is n bits long and a string selector arranged to select m binary strings n bits long from at least a chosen subset of all random binary strings of a predetermined length. The apparatus (100) may further comprise a logical operator arranged to perform a logical function for each of the k samples with each of the selected binary strings to provide a vector, a memory arranged to store a matrix of the vectors generated from k samples, and an address generator arranged to generate RAM address segments from the matrix. In embodiments, the apparatus (100) may comprise a processor for, for example, pattern matching; feature detection, image recognition.

Abstract: An optical correlation apparatus is taught which provides a parallel optical signal having a phase modulation representing input data to which a parallel phase modulation based on reference data is applied. In the event of correlation the resulting wavefront is planar and can be interferometrically coupled to give a high intensity signal. The invention involves use of parallel amplitude modulation means for selectively blocking the optical signal in one or more of the channels of the parallel optical signal which allows different sized reference data strings to be searched more easily and also aids in calibration.