Wavefront Detection Across Multiple Bandwidth Filters
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Solution Overview
Problem
Existing methods for detecting the position of a wavefront in a signal received by a detector are unreliable, especially in noisy environments, as they fail to distinguish between the wavefront corresponding to the desired event and noise, and can be affected by low-frequency noise or high thresholds, leading to incorrect detection or failure in detection.
Innovation Solution
The method involves filtering the signal multiple times with a bandpass filter of varying bandwidth, processing each filtered signal for wavefront detection, and identifying points in a Cartesian frame to find an exponential asymptote, ensuring that the detected wavefront corresponds to the event sought by eliminating noise and confirming consistency across filtered signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single bandpass filter is used to detect wavefronts, then detection speed is improved, but reliability deteriorates due to noise interference
Solution Approach 1:
The detection process is segmented into multiple independent filtering operations with different bandwidths. Instead of using a single filter, the patent applies N≥2 different bandpass filters to the same signal, each producing a separate wavefront detection result. This segmentation allows the system to compare results across different frequency bands, identifying consistent wavefront detections that appear across multiple filters while filtering out noise that only appears in specific bands.
Solution Approach 2:
The patent changes the bandwidth parameter of the bandpass filter across multiple filtering operations. By varying the bandwidth parameter (using different filter configurations with different passband widths), the system analyzes the signal from multiple frequency perspectives. Wavefronts that consistently appear across different bandwidth settings are identified as genuine events, while noise that appears only in specific bandwidth conditions is rejected.
2Reliability
If the threshold is increased to avoid false detections from noise, then false positive rate is reduced, but detection sensitivity deteriorates and no detection is possible when threshold exceeds maximum signal amplitude
Solution Approach 1:
The threshold comparison operation is segmented and applied independently to multiple filtered signals with different bandwidths. Each filtered signal generates its own set of wavefront candidates that must exceed the threshold. By requiring consistent detection across multiple segmentation results, the system maintains sensitivity while reducing false positives, as genuine wavefronts will exceed the threshold in multiple filtered versions while noise will not consistently do so.
Solution Approach 2:
The system uses feedback from multiple filtering results to validate wavefront detections. Each filtered signal's detection results are fed back into a consistency check that compares wavefront positions across different bandwidths. This feedback mechanism allows the system to maintain a fixed threshold while dynamically adjusting which detections are accepted based on their consistency across multiple filtering operations.
3Reliability
If multiple filtering operations are performed to improve reliability, then detection reliability is improved, but computational complexity increases
Solution Approach 1:
The computational work is segmented into N independent filtering operations that can be performed in parallel rather than sequentially. Each filter processes the input signal independently, producing separate wavefront detection results. This segmentation enables parallel computation, reducing the overall processing time and computational burden despite performing multiple filtering operations, as the operations do not depend on each other's results.
4Object-affected harmful factors
If the passband width is decreased to filter out low-frequency noise, then noise rejection is improved, but the wavefront amplitude becomes lower than noise amplitude and detection fails
Solution Approach 1:
The patent changes the bandwidth parameter across multiple filtering operations rather than using a single narrow bandwidth. By applying filters with progressively different bandwidths (from wider to narrower), the system captures wavefront signals at different frequency resolutions. Wavefronts that are detectable across multiple bandwidth settings are identified as genuine events, while low-frequency noise that only appears in wider bandwidths or is absent in narrower bandwidths is rejected through consistency checking.
Data Source
AI summary
The invention relates to a method for detecting the position of a wavefront indicating the occurrence of a researched event in a time signal received by a detector, wherein: digitizing the signal received by the detector in order to a obtain a work signal; filtering the work signal N4 times with a band pass filter in order to obtain N4 filtered work signals having different pass bands; processing the N4 filtered work signals according to a peak detection method for detecting for each signal the position of a first wavefront in terms of arrival time; placing, in a frame of reference, N4 points having an ordinate representing one of the arrival times and an abscissa representing the width of the associated band; searching an exponential asymptote extending through a maximum of the N4 points, the position of the wavefront being the ordinate of a point on or practically on the asymptote and having the maximum abscissa.