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US 7,613,323 B2Granted
Method and apparatus for determining camera pose
AssigneeSarnoff Corporation
InventorsDavid Nister, James Bergen
Life of this patent
Estimating the term…
Abstract
A method and apparatus for determining camera pose characterized by six degrees of freedom (e.g., for use in computer vision systems) is disclosed. In one embodiment an image captured by the camera is received, and at least two constraints on the potential pose are enforced in accordance with known relations of the image to the camera, such that the potential pose is constrained to two remaining degrees of freedom. At least one potential pose is then determined in accordance with the remaining two degrees of freedom.
Claims19
A computer implemented method for determining at least one potential pose of an image capturing device, said at least one potential pose having six degrees of freedom, the method comprising:
- using a processor to perform the steps of:
- receiving an image captured by said image capturing device, said image including images of at least:
- a first know world point, a second known world point and a third known world point;
- and
- imposing constraints on said at least one potential pose in accordance with known relations of said image to said image capturing device, said imposing comprising:
- enforcing constraints given by a first ray, a second ray and a third ray, where said first ray, said second ray and said third ray each project from said image capturing device to, respectively, said first known world point, said second known world point and said third known world point,
- wherein said enforcing constraints given by said first ray and said second ray constrains said at least one potential pose to two remaining degrees of freedom;
- and
- wherein a first of said two remaining degrees of freedom constrains a position of said third known world point relative to said image capturing device within an area defined by a circle and a second of said two remaining degrees of freedom constrains a position of said third ray relative to said image capturing device within an area defined by a ruled quartic surface, said circle and said ruled quartic surface having a plurality of intersection points;
- and
- determining said at least one potential pose in accordance with said constraints,
- wherein said determining comprises the steps of:
- lining up said first ray, said second ray, and said third ray in their canonical positions;
- lining up said first known world point, said second known world point, and said third known world point in their canonical positions;
- computing coefficients of two plane equations representing said third ray;
- computing coefficients of an octic polynomial whose roots correspond to said plurality of intersection points of said circle with said ruled quartic surface;
- extracting the roots of said octic polynomial;
- and
- backsubstituting with each root of the octic polynomial to get solutions for the transformation between the coordinate system of said first known world point, said second known world point and said third known world point and the coordinate system of said first ray, said second ray and said third ray.
16 more elements
A computer-readable memory having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, cause the processor to perform the steps of a method for determining at least one potential pose of an image capturing device, said at least one potential pose having six degrees of freedom, the method comprising:
- receiving an image captured by said image capturing device, said in age including images of at least:
- a first known world point, a second known world point and a third known work point;
- and
- enforcing constraints on said at least one potential pose in accordance with known relations of said image to said image capturing device, said enforcing comprising;
- enforcing constraints given by a first ray, a second ray and a third ray, where said first ray, said second ray and said third ray each project from said image capturing device to, respectively, said first known world point, said second known world point and said third known world point, wherein said enforcing constraints given by said first ray and said second ray constrains said at least one potential pose to two remaining degrees of freedom;
- and
- wherein a first of said two remaining degrees of freedom constrains a position of said third known world point relative to said image capturing device within an area defined by a circle and a second of said two remaining degrees of freedom constrains a position of said third ray relative to said image capturing device within an area defined by a ruled quartic surface, said circle and said ruled quartic surface having a plurality of intersection points;
- and determining at least one potential pose in accordance with said constraints,
- wherein said determining comprises the steps of;
- lining up said first ray, said second ray, and said third ray in their canonical positions;
- lining up said first known world point, said second known world point, and said third known world point in their canonical positions;
- computing coefficients of two plane equations resenting said third ray;
- computing coefficients of an octic polynomial whose roots correspond to said plurality of intersection points of said circle with said ruled quartic surface;
- extracting the roots of said octic polynomial;
- and
- backsubstituting with each root of the octic polynomial to get solutions for the transformation between the coordinate system of said first known world point, said second known world point and said third known world point and the coordinate system of said first ray, said second ray and said third ray.
13 more elements
An apparatus for determining at least one potential pose of an image capturing device, said potential pose having six degrees of freedom, the apparatus comprising:
- means for receiving an image captured by said image capturing device, said image including images of at least:
- a first known world point, a second known world point and a third known world point;
- and
- means for enforcing constraints on said at least one potential pose in accordance with known relations of said image to said image capturing device. said means for enforcing comprising:
- means for enforcing constraints given by a first ray, a second ray an a third ray, where said first ray, said second ray and said third ray each project from said image capturing, device to, respectively, said first known world point, said second known world point and said third known world point, wherein said means for enforcing constraints given said first ray and said second ray constrains said at least one potential pose to two remaining degrees of freedom;
- and
- wherein a first of said two remaining degrees of freedom constrains a position of said third known world point relative to said image capturing device within an area defined by a circle and a second of said two remaining degrees of freedom constrains a position of said third ray relative to said image capturing device within an area define by a ruled quartic surface, said circle and said ruled quartic surface having a plurality of intersection points;
- and
- means for determining at least one potential pose in accordance with said constraints wherein said means for determining comprises:
- means for lining up said first ray said second ray and said third ray in their canonical positions:
- means for lining up said first known world point, said second known world point, and said third known world point in their canonical positions;
- means tor computing coefficients of two plane equations representing said third ray;
- means for computing coefficients of an octic polynomial whose roots correspond to said plurality of intersection points of said circle with said ruled quartic surface;
- means for extracting the roots of said octic polynomial;
- and
- means for backsubstituting with each root of the octic polynomial to get solutions for the transformation between the coordinate system of said fist known world point, said second known world point and said third known world point and the coordinate system of said first ray, said second ray and said third ray.
13 more elements
Dependencies are inferred from the claim text.