Ear-worn Accelerometers for Automatic Ear-to-Ear Distance Measurement
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Solution Overview
Problem
Current methods for determining the ear-to-ear distance in virtual sound presentation systems, such as headsets and hearing aids, are cumbersome and prone to inaccuracy, requiring manual measurement or complex equipment setups.
Innovation Solution
A method using ear-worn sound generating objects with first and second accelerometers arranged to measure acceleration components intersecting at a right angle, allowing for automatic determination of the ear-to-ear distance based on these measurements and a model representing the head's shape, eliminating the need for user involvement and integrating seamlessly with existing software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurement of ear-to-ear distance is used, then the measurement can be performed with simple equipment, but the process is cumbersome and prone to inaccuracy
Solution Approach 1:
The patent replaces manual mechanical measurement with an automatic sensor-based system. Accelerometers and gyroscopes detect head motion, and a processor automatically calculates ear-to-ear distance based on the motion data and a head model, eliminating the need for manual measurement while improving both accuracy and convenience
Solution Approach 2:
The system performs self-measurement by using the wearer's own head motions to automatically determine ear-to-ear distance. The sensors on the headset detect the wearer's natural head movements and compute the distance without requiring external measurement tools or manual intervention
2Measurement precision
If acoustic time delay method is used to determine head size, then equipment communication is established, but the acoustic distance does not accurately represent Euclidean distance between ears
Solution Approach 1:
The patent replaces acoustic measurement methods with inertial measurement using accelerometers and gyroscopes. The system detects head motions mechanically and uses these motion data combined with a head model to calculate Euclidean distance, providing more accurate geometric information than acoustic time delay methods
Solution Approach 2:
The system changes the measurement parameter from acoustic time delay to inertial motion parameters. By measuring acceleration and angular velocity during head motion and combining these with a head model, the system directly computes Euclidean distance, preserving geometric information that is lost in acoustic measurements
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 and automatic adjustment of ear-to-ear distance, improving the fidelity of virtual audio signals and enabling more advanced beamforming models, particularly in hearing aids, by accurately determining head size and enhancing speech signal direction estimation.
Implementation Method 1
the first sound generating object comprises a first accelerometer and a second accelerometer, the respective accelerometers, i.e. the first accelerometer and the second accelerometer, being arranged to measure at least an acceleration component (a1, a2) intersecting at a substantially right angle a center axis of the wearer's head
Data Source
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Figure 3
AI summary
A method for determining a distance (D) between ears of a wearer of a sound generating object is disclosed. The method comprises the steps of: selecting a model for representing shape of the head (2) of the wearer of the sound generating object (4) so as to obtain a center axis (6) of the wearer's head. The subsequent step is to associate the first sound generating object with an ear of the wearer, wherein the first sound generating object comprises first (10) and second accelerometers (12), the respective accelerometers being arranged to measure at least an acceleration component (a1, a2) intersecting at a substantially right angle a center axis of the wearer's head. The two accelerometers are so arranged that a straight line (14) that intersects the center axis of the wearer's head at a substantially right angle crosses the two accelerometers such that the acceleration components (a1, a2) have the same direction, said two accelerometers being spaced by a known distance (∆r). The method further comprises a step of, when the head of the wearer is in motion, determine, by means of the first accelerometer, a value of the first acceleration component (a1) and, by means of the second accelerometer, a value of the second acceleration component (a2). In another step, on the basis of the obtained values of the acceleration components (a1, a2), the distance (D) between the ears of the wearer is determined. The disclosure also regards a first, ear-worn, sound generating object comprising two accelerometers.