System for computing the self-motion of moving images devices
First Claim
1. An imaging device capable of determining its own self-motion from its imaging, comprising:
- imaging means for detecting a sequence of images in a field of view;
token tracking means, connected to said imaging means, for determining two-dimensional displacement vectors of selected tokens for each consecutive pair of images, and wherein said token tracking means tracks stationary parts of a visual environment in the images, using two-dimensional, references such as corner points, contour segments, region boundaries as references, from image to image, wherein the two-dimensional displacement vectors are the result of camera motion;
seeker means, connected to said token tracking means, for selecting candidate locations for focus of expansion under forward translation of said imaging means and for focus of contraction under backward translation of said imaging device, for forming a connected image region of the candidate locations and a range of corresponding rotations, and for outputting focus of expansion or contraction and image rotation estimates; and
optimal rotation means, connected to said token tracking means and to said seeker means, for determining optimal three-dimensional rotation angles plus an error value for a selected candidate location for focus of expansion or contraction.
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Abstract
Determining the self-motion in space of an imaging device (e.g., a television camera) by analyzing image sequences obtained through the device. Three-dimensional self-motion is expressed as a combination of rotations about the horizontal and vertical camera axes and the direction of camera translation. The invention computes the rotational and translational components of the camera self-motion exclusively from visual information. Robust performance is achieved by determining the direction of heading (i.e., the focus of expansion) as a connected region instead of a single location on the image plane. The method can be used to determine when the direction of heading is outside the current field of view and when there is zero or very small camera translation.
114 Citations
10 Claims
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1. An imaging device capable of determining its own self-motion from its imaging, comprising:
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imaging means for detecting a sequence of images in a field of view; token tracking means, connected to said imaging means, for determining two-dimensional displacement vectors of selected tokens for each consecutive pair of images, and wherein said token tracking means tracks stationary parts of a visual environment in the images, using two-dimensional, references such as corner points, contour segments, region boundaries as references, from image to image, wherein the two-dimensional displacement vectors are the result of camera motion; seeker means, connected to said token tracking means, for selecting candidate locations for focus of expansion under forward translation of said imaging means and for focus of contraction under backward translation of said imaging device, for forming a connected image region of the candidate locations and a range of corresponding rotations, and for outputting focus of expansion or contraction and image rotation estimates; and optimal rotation means, connected to said token tracking means and to said seeker means, for determining optimal three-dimensional rotation angles plus an error value for a selected candidate location for focus of expansion or contraction. - View Dependent Claims (2, 3, 4)
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5. An imaging system capable of determining its self-motion from its imaging, comprising:
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derotation means for derotating two-dimensional displacement vectors from consecutive pairs of two-dimensional images to remove rotational effects of said imaging system; first computing means, connected to said derotation means, for computing a fuzzy focus of expansion (FOE) from the two-dimensional displacement vectors, wherein the fuzzy FOE is a two-dimensional region of possible focus-of-expansion locations on a two-dimensional image; and second computing means, connected to said derotation means, for computing self-motion parameters of said imaging system, from the fuzzy FOE. - View Dependent Claims (6)
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7. An imaging system in an environment, capable of determining its self-motion from its imaging, comprising:
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computing means for computing possible focus of expansion (FOE) locations within images of said imaging system, from two-dimensional displacement vectors; combining means, connected to said computing means, for combining possible FOE locations, thereby resulting in a fuzzy FOE that indicates approximate direction of heading and amount of rotation in space of said imaging system; and derotation means, connected to said computing means, for removing rotation of said imaging system from the images so as to output derotated two-dimensional displacement vectors to said computing means. - View Dependent Claims (8)
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9. A method for determining self-motion of an imaging system in an environment, comprising:
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computing a focus of expansion (FOE) location from two-dimensional displacement vectors of successive two-dimensional images; computing a fuzzy FOE region that is a qualitative indication the FOE location, wherein the fuzzy FOE region is an area of possible FOE locations for each image; determining an approximate direction of heading and amount of rotation of said imaging system, relative to its own reference coordinate system, from the fuzzy FOE; and removing the effects of rotation of said imaging system from the displacement vectors. - View Dependent Claims (10)
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Specification