Navigation in buildings with rectangular floor plan
First Claim
1. A method of navigation in a mobile device using a reference wall, the method comprising:
- determining a reference angle (θ
REF) of the reference wall, comprising;
determining a building containing the reference wall;
finding the building on an overhead map; and
computing the reference angle (θ
REF) from the overhead map;
capturing, with a camera in the mobile device, a local image containing a horizontal feature;
processing the local image to determine a horizontal feature angle (θ
HF), wherein the horizontal feature angle (θ
HF) measures an angle from a current orientation of the mobile device to the horizontal feature;
selecting a wall angle, of the horizontal feature, equal to an integer multiple of 90°
from the reference angle (θ
REF); and
determining an angle of the current orientation of the mobile device based on a combination of the horizontal feature angle (θ
HF) and the wall angle.
1 Assignment
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Accused Products
Abstract
An apparatus and method for providing a direction based on an angle of a reference wall is provided. A mobile device uses an angle of a horizontal feature from an image to calibrate a sensor and future sensor measurements. The angle of the horizontal feature is determined by image processing and this angle is mapped to one of four assumed parallel or perpendicular angles of an interior of a building. A sensor correction value is determined from a difference between the sensor-determined angle and the image-processing determined angle. The image processing determined angle is assumed to be very accurate and without accumulated errors or offsets that the sensor measurements may contain.
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Citations
21 Claims
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1. A method of navigation in a mobile device using a reference wall, the method comprising:
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determining a reference angle (θ
REF) of the reference wall, comprising;determining a building containing the reference wall; finding the building on an overhead map; and computing the reference angle (θ
REF) from the overhead map;capturing, with a camera in the mobile device, a local image containing a horizontal feature; processing the local image to determine a horizontal feature angle (θ
HF), wherein the horizontal feature angle (θ
HF) measures an angle from a current orientation of the mobile device to the horizontal feature;selecting a wall angle, of the horizontal feature, equal to an integer multiple of 90°
from the reference angle (θ
REF); anddetermining an angle of the current orientation of the mobile device based on a combination of the horizontal feature angle (θ
HF) and the wall angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A mobile device for navigation using a reference wall, the mobile device comprising:
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a camera; an inertial sensor; and a processor and memory comprising code for; determining a reference angle (θ
REF) of the reference wall, comprising;determining a building containing the reference wall; finding the building on an overhead map; and computing the reference angle (θ
REF) from the overhead map;capturing, with the camera in the mobile device, a local image containing a horizontal feature; processing the local image to determine a horizontal feature angle (θ
HF), wherein the horizontal feature angle (θ
HF) measures an angle from a current orientation of the mobile device to the horizontal feature;selecting a wall angle, of the horizontal feature, equal to an integer multiple of 90°
from the reference angle (θ
REF); anddetermining an angle of the current orientation of the mobile device based on a combination of the horizontal feature angle (θ
HF) and the wall angle.
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20. A mobile device for navigation using a reference wall, the mobile device comprising:
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means for determining a reference angle (θ
REF) of the reference wall, comprising;means for determining a building containing the reference wall; means for finding the building on an overhead map; and means for computing the reference angle (θ
REF) from the overhead map;means for capturing a local image containing a horizontal feature; means for processing the local image to determine a horizontal feature angle (θ
HF), wherein the horizontal feature angle (θ
HF) measures an angle from a current orientation of the mobile device to the horizontal feature;means for selecting a wall angle, of the horizontal feature, equal to an integer multiple of 90°
from the reference angle (θ
REF); andmeans for determining an angle of the current orientation of the mobile device based on a combination of the horizontal feature angle (θ
HF) and the wall angle.
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21. A non-transient computer-readable storage medium including program code stored thereon, for navigation using a reference wall, comprising program code for:
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determining a reference angle (θ
REF) of the reference wall, comprising;determining a building containing the reference wall; finding the building on an overhead map; and computing the reference angle (θ
REF) from the overhead map;receiving, from a camera in the mobile device, a local image containing a horizontal feature; processing the local image to determine a horizontal feature angle (θ
HF), wherein the horizontal feature angle (θ
HF) measures an angle from a current orientation of the mobile device to the horizontal feature;selecting a wall angle, of the horizontal feature, equal to an integer multiple of 90°
from the reference angle (θ
REF); anddetermining an angle of the current orientation of the mobile device based on a combination of the horizontal feature angle (θ
HF) and the wall angle.
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Specification