Real time determination of pedestrian direction of travel
AssigneeApple Inc.
InventorsMark P. Sena, Jaehyun Bae
Life of this patent
Estimating the term…
Abstract
Embodiments are disclosed for real time estimation of DoT. In some embodiments, a method comprises: obtaining inertial acceleration data from a motion sensor of a mobile device worn or held by a user; computing a frequency spectrum of the acceleration data to generate horizontal and vertical frequency components at a step frequency of the user; constructing an acceleration trajectory of the horizontal frequency components in a horizontal reference frame, the horizontal frequency components forming an ellipse in the horizontal reference frame; determining a maximum radius vector of the ellipse; determining an angle to DoT based on the maximum radius vector; disambiguating a sign of the angle; and determining the disambiguated angle as the DoT.
Claims12
A method comprising:
- obtaining, with at least one processor, inertial acceleration data from a motion sensor of a mobile device worn or held by a user;
- computing, with at least one processor, a frequency spectrum of the acceleration data to generate horizontal and vertical frequency components at a step frequency of the user;
- constructing, with the at least one processor, an acceleration trajectory of the horizontal frequency components in a horizontal reference frame, the horizontal frequency components forming an ellipse in the horizontal reference frame;
- determining, with the at least one processor, a maximum radius vector of the ellipse;
- and
- determining, with the at least one processor, an angle to a direction of travel (DoT) of the user based on the maximum radius vector, wherein the angle to the DoT is used for tracking or mapping the user's trajectory, or analyzing the user's walking gait, or used for fitness or spatial audio applications.
An apparatus comprising:
- at least one processor;
- memory storing instructions that when executed by the at least one processor, cause the at least one processor to perform operations comprising:
- obtaining inertial acceleration data from a motion sensor of a mobile device worn or held by a user;
- computing a frequency spectrum of the acceleration data to generate horizontal and vertical frequency components at a step frequency of the user;
- constructing an acceleration trajectory of the horizontal frequency components in a horizontal reference frame, the horizontal frequency components forming an ellipse in the horizontal reference frame;
- determining a maximum radius vector of the ellipse;
- and
- determining an angle to a direction of travel (DoT) of the user based on the maximum radius vector, wherein the angle to the DoT is used for tracking or mapping the user's trajectory, or analyzing the user's walking gait, or used for fitness or spatial audio applications.
A non-transitory computer-readable storage medium having instructions stored thereon, that when executed by one or more processors, perform operations comprising:
- obtaining inertial acceleration data from a motion sensor of a mobile device worn or held by a user;
- computing a frequency spectrum of the acceleration data to generate horizontal and vertical frequency components at a step frequency of the user;
- constructing an acceleration trajectory of the horizontal frequency components in a horizontal reference frame, the horizontal frequency components forming an ellipse in the horizontal reference frame;
- determining a maximum radius vector of the ellipse;
- and
- determining an angle to a direction of travel (DoT) of the user based on the maximum radius vector, wherein the angle to the DoT is used for tracking or mapping the user's trajectory, or analyzing the user's walking gait, or used for fitness or spatial audio applications.
Dependencies are inferred from the claim text.