Camera-based inertial sensor alignment for PND
First Claim
Patent Images
1. A mobile device using images for navigation, the mobile device comprising:
- a camera, wherein the camera acquires a sequence of images;
a memory to hold three rotation matrices comprising;
a first rotation matrix, wherein the first rotation matrix is for converting between a body reference system of the mobile device and a platform reference system of a vehicle;
a second rotation matrix, wherein the second rotation matrix is for converting between the platform reference system of the vehicle and a local reference system; and
a third rotation matrix, wherein the third rotation matrix is for converting between the body reference system and the local reference system; and
a processor coupled to the camera and the memory, wherein the processor is configured to;
set an initial value of the first rotation matrix based on the sequence of images; and
set an initial value of the third rotation matrix based on the sequence of images.
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Abstract
An apparatus and method to enhance dead-reckoning navigation using inertial sensor measurements based on images from a camera are disclosed. A camera build into a mobile device is used to calibrate inertial sensors and rotation matrices. Images from a camera may be used (1) to remove a gravitational element from accelerometer measurements; (2) to set a scaling factor and an offset for a gyrometer; and (3) to set initial and updated values for rotation matrices.
13 Citations
26 Claims
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1. A mobile device using images for navigation, the mobile device comprising:
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a camera, wherein the camera acquires a sequence of images; a memory to hold three rotation matrices comprising; a first rotation matrix, wherein the first rotation matrix is for converting between a body reference system of the mobile device and a platform reference system of a vehicle; a second rotation matrix, wherein the second rotation matrix is for converting between the platform reference system of the vehicle and a local reference system; and a third rotation matrix, wherein the third rotation matrix is for converting between the body reference system and the local reference system; and a processor coupled to the camera and the memory, wherein the processor is configured to; set an initial value of the first rotation matrix based on the sequence of images; and set an initial value of the third rotation matrix based on the sequence of images. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method in a mobile device of using images for navigation, the method comprising:
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acquiring a sequence of images from a camera; setting an initial value of a first rotation matrix based on the sequence of images, wherein the first rotation matrix is for converting between a body reference system of the mobile device and a platform reference system of a vehicle; setting an initial value of a second rotation matrix based on the sequence of images, wherein the second rotation matrix is for converting between the platform reference system of the vehicle and a local reference system; setting an initial value of a third rotation matrix based on the sequence of images, wherein the third rotation matrix is for converting between the body reference system and the local reference system; writing the second rotation matrix to memory; and converting measurements, between a body reference system and a local reference system, using the third rotation matrix. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A mobile device using images for navigation, the mobile device comprising:
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means for acquiring a sequence of images from a camera; means for setting an initial value of a first rotation matrix based on the sequence of images used to convert from a body reference system of the mobile device and a platform reference system of a vehicle; means for setting an initial value of a second rotation matrix based on the sequence of images, wherein the second rotation matrix is for converting between the platform reference system of the vehicle and a local reference system; means for setting an initial value of a third rotation matrix based on the sequence of images, wherein the third rotation matrix is for converting between the body reference system and the local reference system; means for writing the third rotation matrix to memory; and means for converting measurements, between the body reference system of the mobile device and a local reference system, using the third rotation matrix.
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26. A non-transitory computer-readable medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method for using images for navigation in a mobile device having a camera, memory and a processor, said method comprising operations of:
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acquiring a sequence of images from a camera; setting an initial value of a first rotation matrix based on the sequence of images, wherein the first rotation matrix is for converting between a body reference system of the mobile device and a platform reference system of a vehicle; setting an initial value of a second rotation matrix based on the sequence of images, wherein the second rotation matrix is for converting between the platform reference system of the vehicle and a local reference system; setting an initial value of a third rotation matrix based on the sequence of images, wherein the third rotation matrix is for converting between the body reference system and the local reference system; writing the third rotation matrix to memory; and converting measurements, between the body reference system of the mobile device and a local reference system, using the third rotation matrix.
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Specification