Optical Correlator Using Delay Lines for High-Speed Pattern Recognition
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Solution Overview
Problem
Existing pattern recognition systems, especially those using optical techniques, face limitations in speed and efficiency when dealing with high data rates and large data repositories, as they require rapid updates of spatial light modulators and struggle to perform correlations at the speed of high-speed data streams.
Innovation Solution
An optical correlation apparatus that converts temporal data streams into parallel optical data streams with phase modulation, using an optical delay means and a reference phase modulator to create a spatial phase pattern, allowing for correlation based on simple spatial techniques without the need for rapid SLM updates, enabling high-speed correlation even at very high input data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If software based pattern identification techniques are used to search large amounts of data, then pattern recognition can be performed, but the system becomes slow and requires very large processing power
Solution Approach 1:
The patent replaces electronic/software-based pattern recognition with an optical correlation system. The optical system uses light propagation and interference to perform correlations physically, eliminating the need for software processing. The optical correlator uses a spatial light modulator to load reference patterns and an optical processor to perform parallel correlations at the speed of light, achieving high-speed pattern recognition without requiring large electronic processing power.
2Productivity
If optical pattern recognition systems are used to search data repositories, then correlation can be performed, but the system requires rapid updates of the spatial light modulator which limits the speed of correlation
Solution Approach 1:
The patent applies preliminary action by pre-processing the input data stream into a delayed parallel optical signal before it reaches the spatial light modulator. The optical delay line creates multiple time-delayed copies of the input signal in parallel, so that when the SLM is updated with new reference patterns, the correlation can immediately proceed with the pre-processed parallel signal. This eliminates the bottleneck of SLM update speed because the signal transformation is already complete before the SLM update is needed.
3Speed
If optical techniques are used for pattern recognition at high data rates, then correlation speed can be increased, but the system struggles to perform correlations at the speed of high-speed data streams
Solution Approach 1:
The patent transforms the temporal dimension of the input data stream into the spatial dimension by creating a delayed parallel optical signal. The optical delay line converts a single time-varying signal into multiple spatially separated signals with different time delays. This dimensional transformation allows the system to process high-speed data streams in parallel spatial channels, achieving correlation speeds that match high-data-rate applications by exploiting spatial parallelism rather than temporal sequencing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly enhances correlation speeds beyond existing optical and electronic systems, allowing for efficient pattern recognition at high data rates without the limitations of SLM update speed, and supports parallel correlations for multiple reference patterns.
Implementation Method 1
an optical delay means for converting a temporal input data stream to at least one parallel optical data stream having a phase modulation replicating the input data
Implementation Method 2
a reference phase modulator for applying a parallel phase modulation replicating at least one reference data set wherein the reference phase modulator and optical delay means are aligned so as to create a parallel optical signal which has been modulated in phase according to both input and reference data
Data Source
AI summary
This invention relates to a pattern recognition correlator and method for correlating input data with one or more reference data sets. The input data, which may be for instance digital amplitude modulated optical data, is used to modulate an optical signal to form a phase modulated optical signal. This temporal phase modulated optical signal is then converted into a parallel optical phase signal, preferably through use of an optical delay, and modulated by an optical phase modulator. When there is a correlation between the input data and the reference data the emerging wavefront is plane and can be strongly coupled to a detector. In the absence of correlation the emergent wavefront is not plane and so is not coupled as strongly to the detector. The detector output can therefore be used as an indication of correlation.