Mobile robot navigation employing retroreflective ceiling features
First Claim
1. Navigation apparatus for generating navigation related information for a vehicle, comprising:
- means for obtaining an image of a surface which overlies a vehicle or a projected path of the vehicle, the surface having one or more retroreflective features disposed thereon;
means for illuminating the retroreflective features;
means, coupled to said obtaining means, for detecting a location within the image of the one or more retroreflective features; and
means, coupled to said detecting means, for generating, from the detected feature location or locations, at least vehicle position and orientation information, whereinsaid image obtaining means comprises means for forming a two-dimensional image comprised of a plurality of image pixels,wherein said detecting means comprises means, coupled to said two-dimensional image forming means, for identifying pixels which correspond to two opposing edges of the retroreflective feature, andwherein said generating means comprises means, coupled to said pixel identifying means, for projecting a line from the pixels that correspond to each of the opposing edges of the feature, an intersection of the projected lines defining a vanishing point.
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Accused Products
Abstract
Apparatus and method which provides for the determination of a vehicle'"'"'s orientation and position in an environment, such as a hallway, from an image of a retroreflective ceiling feature. A mobile robot 10 includes a light source 28 and a camera 12 that are pitched up obliquely at an intermediate angle between a horizon and a zenith. The camera views a ceiling having one or more strip-like retroreflective features 16 which are preferably aligned with an axis of the hallway. In that the feature presents a pattern or alignment which is substantially parallel to a long axis of the hallway the pattern is detected and processed to derive robot navigation information therefrom.
426 Citations
25 Claims
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1. Navigation apparatus for generating navigation related information for a vehicle, comprising:
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means for obtaining an image of a surface which overlies a vehicle or a projected path of the vehicle, the surface having one or more retroreflective features disposed thereon; means for illuminating the retroreflective features; means, coupled to said obtaining means, for detecting a location within the image of the one or more retroreflective features; and means, coupled to said detecting means, for generating, from the detected feature location or locations, at least vehicle position and orientation information, wherein said image obtaining means comprises means for forming a two-dimensional image comprised of a plurality of image pixels, wherein said detecting means comprises means, coupled to said two-dimensional image forming means, for identifying pixels which correspond to two opposing edges of the retroreflective feature, and wherein said generating means comprises means, coupled to said pixel identifying means, for projecting a line from the pixels that correspond to each of the opposing edges of the feature, an intersection of the projected lines defining a vanishing point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Navigation apparatus for generating navigation related information for a mobile robot, comprising:
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means for imaging at least a portion of a ceiling disposed over a forward path of a mobile robot, said imaging means including means for forming a two-dimensional image represented as a two-dimensional array having rows and columns of image pixels; means for searching the two-dimensional array of image pixels to identify two-dimensional array coordinates of image pixels, located in a plurality of rows of the two dimensional array, that correspond to oppositely disposed boundaries of at least one substantially linear retroreflective ceiling feature; means for generating a reference axis of robot motion relative to the identified two-dimensional array coordinates of the image pixels located in the plurality of rows of the two-dimensional array; and means for determining a position of the robot relative to the reference axis of robot motion. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of providing navigation related information for a mobile robot, comprising the steps of:
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obtaining at least one image of a ceiling having one or more distinct retroreflective linear visual features, the ceiling overlying at least a projected path of the robot; locating within the ceiling image the one or more distinct retroreflective linear visual features; detecting an edge boundary of at least one of the features; generating at least one reference line relative to the edge detected boundary; and determining a location of the robot relative to the at least one reference line, wherein the step of generating at least one reference line includes a step of projecting perspective lines along detected edge boundaries, an intersection of the projected perspective lines defining a vanishing point. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method of providing navigation information for a vehicle, comprising the steps of:
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imaging a surface which is disposed above at least a projected forward path of the vehicle, the surface having a height zO above the vehicle, the surface including one or more substantially linear retroreflective features; detecting along a first image scan line two opposing edges of the feature; detecting along a second image scan line two opposing edges of the feature; determining a vanishing point relative to the image from the detected opposing edges, an axis of vehicle alignment intersecting the vanishing point; projecting the axis of alignment onto the image to obtain a slope m; determining a pitch (Pch) component and a yaw (Yaw) component of vehicle orientation relative to the axis of alignment; and determining a lateral displacement xO of the vehicle from the axis of alignment in accordance with the equation;
space="preserve" listing-type="equation">xO=-zO×
cos(Yaw)/(m×
cos(Pch))-zO×
sin(Pch×
sin(Yaw)/cos(Pch). - View Dependent Claims (25)
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Specification