Movement Direction Detection from Anti-Periodic Acceleration
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Solution Overview
Problem
Determining user movement direction is challenging due to artifacts in sensor data caused by head movements during activities like walking or running, especially when the user looks around, leading to inaccurate spatial rendering of audio content.
Innovation Solution
A method to determine movement direction using user acceleration data, identifying a movement period and orthogonal acceleration direction, and transforming data from a user-centered to a fixed coordinate frame, allowing accurate determination of movement direction irrespective of head orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If user acceleration data is used to determine movement direction, then movement direction can be obtained, but artifacts in sensor data due to head movements cause inaccurate determination
Solution Approach 1:
The acceleration data is segmented into periodic movement cycles, and the anti-periodic component is isolated by comparing consecutive periods. This segmentation allows separation of genuine movement direction signals from head movement artifacts, improving measurement precision while maintaining reliability.
Solution Approach 2:
Instead of directly analyzing the acceleration data for movement direction, the patent inverts the approach by analyzing what is NOT periodic (anti-periodic component). The movement direction is determined from the anti-periodic acceleration component, which represents the true movement direction orthogonal to the periodic head movement artifacts.
2Measurement precision
If head orientation data is used to transform acceleration data to fixed coordinate frame, then accurate movement direction can be determined, but device complexity increases
Solution Approach 1:
The head orientation sensor serves multiple functions: it provides the rotation data needed for coordinate frame transformation and also characterizes the user's looking direction. This multi-functionality allows accurate movement direction determination without adding separate sensors, thus managing device complexity while improving measurement precision.
Solution Approach 2:
The head orientation data acts as an intermediary that bridges the user-centered coordinate frame and the fixed coordinate frame. By using the head orientation as a mediator, the patent enables accurate coordinate transformation without requiring complex direct measurement systems, balancing measurement precision with device complexity.
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
Enables accurate determination of movement direction, enabling faithful spatial rendering of audio content aligned with the user's torso, even when head orientation varies.
Implementation Method 1
obtain, using an accelerometer, user acceleration data in the vertical direction associated with a movement activity of a user
Data Source
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AI summary
Methods, systems, and media for determining user movement direction are provided. In some embodiments, a method involves obtaining, using a control system, user acceleration data associated with a user. The method involves determining, using the control system, a movement period associated with a movement activity of the user using the user acceleration data, wherein the movement period indicates a duration between two sequential movements by the user. The method involves determining, using the control system, a movement direction corresponding to the movement activity using the user acceleration data based on a direction of acceleration orthogonal to the movement direction in which at least a portion of the user acceleration data is anti-periodic over a period of time corresponding to the movement period.