Iterative Transducer Array Calibration via Time Delay Denoising
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Solution Overview
Problem
Calibrating transducer arrays using time delay measurements is challenging due to noise, faulty transducers, and missing data, which inhibits accurate and robust calibration.
Innovation Solution
An iterative method that forms and modifies time delay measurement data sets, denoises distance data, and updates transducer positions using estimated calibration parameters, incorporating an iterative masking approach to recover missing data and mitigate noise, thereby providing accurate and robust calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time delay measurements are used for calibration, then calibration parameters can be estimated, but noise and faulty data reduce measurement precision
Solution Approach 1:
The patent extracts and removes faulty or noisy measurements from the calibration data set before performing parameter estimation. This is achieved through statistical methods that identify and eliminate outlying measurements that would otherwise degrade the precision of calibration parameter estimates.
Solution Approach 2:
The patent employs iterative calibration methods where initial parameter estimates are used to evaluate measurement quality, which then feeds back into selecting a refined data set for improved parameter estimation. This feedback loop continues until convergence, progressively improving measurement precision by eliminating noisy data.
2Reliability
If all available time delay measurements are used, then more calibration parameters can be estimated, but faulty transducers lead to unreliable results
Solution Approach 1:
The patent changes the state of calibration by transforming raw time delay measurements into processed measurements with associated reliability metrics. This parameter transformation enables the system to distinguish between reliable and faulty measurements, improving overall calibration robustness.
Solution Approach 2:
The patent performs preliminary evaluation of measurement quality before final parameter estimation. By pre-identifying and excluding faulty measurements in advance, the system ensures that only reliable data contributes to the calibration process, enhancing robustness against faulty transducers.
3Measurement precision
If iterative calibration methods are used, then accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies partial iteration by performing calibration steps only as many times as necessary to achieve a predetermined accuracy threshold. Rather than exhaustive iteration, the method stops when sufficient precision is reached, reducing computational complexity while maintaining adequate accuracy.
Solution Approach 2:
The patent segments the calibration process into distinct stages: initial parameter estimation, measurement quality evaluation, faulty data elimination, and refined parameter estimation. This segmentation allows each stage to be optimized independently, reducing overall computational complexity while maintaining precision.
Data Source
AI summary
An iterative method for calibrating a transducer array characterized by calibration parameters, based on time delay measurements between transducer pairs, comprising the steps of: creating a distance data set that includes pairwise distances between estimated positions of transducer; forming a time delay measurement data set that includes time delay measurements between transducer pairs; generating from the time delay measurement data set an estimate of at least one calibration parameter; modifying the time delay measurement data set and the distance data set based on the estimated calibration parameters; denoising the modified distance data set with an iterative algorithm; updating the estimated positions of transducers based on the denoised modified distance data set; and repeating at least a portion of the steps until the difference between the estimated positions of transducer pairs and updated estimated positions of transducers satisfies a stopping criterion.