Method and apparatus for optical odometry
First Claim
Patent Images
1. An optical odometer system for measuring travel over a surface, comprising:
- an electronic image sensor having freedom of motion parallel to said surface in at least one dimension;
optics coupled to said image sensor so as to image a portion of said surface onto said image sensor at a known scale factor;
an analog-to-digital converter for converting a sensed image to digital form;
computer memory for storing data derived from sequentially captured digital images;
a clock oscillator for providing a time reference; and
distance calculating means for calculating distance traveled with respect to said surface between sequentially captured digital images.
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Abstract
A method and apparatus for optical odometry are disclosed which inexpensively facilitate diverse applications including indoor/outdoor vehicle tracking in secure areas, industrial and home robot navigation, automated steering and navigation of autonomous farm vehicles, shopping cart navigation and tracking, and automotive anti-lock braking systems. In a preferred low-cost embodiment, a telecentric lens is used with an optical computer mouse chip and a microprocessor. In a two-sensor embodiment, both rotation and translation are accurately measured.
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Citations
24 Claims
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1. An optical odometer system for measuring travel over a surface, comprising:
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an electronic image sensor having freedom of motion parallel to said surface in at least one dimension;
optics coupled to said image sensor so as to image a portion of said surface onto said image sensor at a known scale factor;
an analog-to-digital converter for converting a sensed image to digital form;
computer memory for storing data derived from sequentially captured digital images;
a clock oscillator for providing a time reference; and
distance calculating means for calculating distance traveled with respect to said surface between sequentially captured digital images. - View Dependent Claims (2, 3, 4, 6, 7, 8, 20, 21, 22, 23, 24)
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5. A method of optical odometry comprising the steps of:
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mounting optics operably coupled to an electronic imager on a mobile object capable of motion with at least one degree of freedom parallel to a surface, such that said optics focus an image of a portion of said surface onto said electronic imager at a known scale factor, said portion of said surface varying with the position of said object;
acquiring a sequence of electronic images at known times through said imager;
converting said sequence of electronic images to a sequence of data sets; and
digitally processing said sequence of data sets in conjunction with said scale factor to measure distance traveled by said object in at least one dimension.
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9. A method of providing automated shopping assistance, comprising:
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using an optical odometer attached to a shopping cart to track motion of said shopping cart through a retail store; and
displaying information of potential use to a consumer 0 through a display on said shopping cart. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An optical odometer system for measuring travel over a surface, comprising:
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an integrated optical navigation sensor having freedom of motion parallel to said surface in at least one dimension;
optics coupled to said image sensor so as to image a portion of said surface onto said electronic image sensor at a known scale factor;
a clock oscillator for providing a time reference; and
distance calculating means for calculating distance traveled with respect to said-surface based data output from said integrated optical navigation sensor. - View Dependent Claims (17)
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18. A method of optical odometry comprising the steps of:
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mounting optics operably coupled to an integrated navigation sensor on a mobile object capable of motion with at least one degree of freedom parallel to a surface, such that said optics focus an image of a portion of said surface onto said electronic imager at a known scale factor, said portion of said surface varying with the position of said object, and said image being of a known scale relative to said portion of said surface; and
digitally processing data output from said optical navigation sensor to derive distance traveled by said object in at least one dimension. - View Dependent Claims (19)
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Specification