Acoustic Transducer Array Object Tracking via Waveform Similarity
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Solution Overview
Problem
Traditional source localization techniques, such as trilateration and multilateration, are limited by the requirement for multiple reliable measurements and assume a common point-like source, which restricts their accuracy and applicability, especially when the distance between receivers is comparable to the object's size or tracking distances, and they fail to detect the presence or absence of an object effectively.
Innovation Solution
The proposed method uses waveform similarity recorded by a rectangular array of transducers to determine the presence or absence of an object and its coarse location, employing correlation coefficients and covariance calculations to identify the quadrant where the object is located, and implements source localization algorithms that can function with as few as two receivers by constraining one dimension, overcoming the limitations of traditional techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional source localization techniques (trilateration and multilateration) are used, then object location can be estimated, but at least four reliable measurements are required and the system assumes a common point-like source, which limits accuracy when receiver distances are comparable to object dimensions
Solution Approach 1:
The patent divides the array of transducers into four distinct quadrants, with each quadrant containing a receiving element at its center. This segmentation allows the system to process acoustic signals from different spatial regions independently, enabling location estimation with fewer receivers while maintaining accuracy even when receiver distances are comparable to object dimensions.
Solution Approach 2:
The patent transitions from traditional point-source localization to a distributed source model by treating the hand as an extended object with acoustic reflections from multiple points. By utilizing the spatial distribution of receivers across quadrants and analyzing waveform similarities in different dimensional contexts, the system achieves accurate localization without requiring the minimum four receivers mandated by traditional trilateration.
2Reliability
If traditional source localization techniques are used, then location estimation is possible, but they fail to effectively detect the presence or absence of an object
Solution Approach 1:
The patent implements a feedback mechanism by comparing the acoustic waveform received at each quadrant's center element with the expected waveform pattern. When an object is present, the reflected acoustic signal modifies the received waveform, creating a detectable deviation from the baseline. This feedback loop enables reliable detection of object presence or absence by continuously monitoring waveform similarities and identifying anomalies that indicate an object's presence in the acoustic field.
3Measurement precision
If waveform similarity comparison is used across all quadrants, then object presence can be detected and coarse location identified, but computational complexity increases
Solution Approach 1:
The patent segments the computational task by assigning each quadrant's center element to independently compare its received waveform against reference patterns. This division of computational labor allows parallel processing of waveform similarities across quadrants, reducing the overall computational burden while maintaining the ability to detect object presence and identify coarse location through systematic comparison of acoustic signatures from different spatial regions.
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 enables accurate detection of object presence and location estimation without the need for multiple receivers, reducing hardware and computational costs, and allows for object tracking in scenarios where traditional methods fail, providing robust hand tracking and gesture recognition capabilities.
Implementation Method 1
An array of transducers can be used to create a continuous acoustic field, in the form of a distribution of sound energy
Implementation Method 2
A rectangular array of transducers is divided into four parts (quadrants), on the basis that each quadrant contains a receiving element in its center
Data Source
AI summary
A method for object tracking is presented based on the similarity of waveforms recorded at the receiving elements of the array. A rectangular array of acoustic transducers is divided into four quadrants, on the basis that each quadrant contains a receiving element in its center. Each of the four recorded waveforms are compared against each of the remaining waveforms to identify either absolute similarity of the signal characteristics, which would denote absence of the object, or identifying a waveform being the least similar from the rest, hence pointing to a part of the array above which the object is located. Further, source localization algorithms are used for ill-posed scenarios where the distance between receivers is on the same order of magnitude of the dimensions of the tracked object and of the tracking distances.