US 5,499,306 AGranted

Position-and-attitude recognition method and apparatus by use of image pickup means

AssigneeNippondenso Co., Ltd.

InventorsMikio Sasaki, Yukihiro Kanayama, Hideki Saitou, Tetsuya Kominami

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Abstract

A positional relationship between an autonomous mobile robot and a workpiece to be handled by the robot is calculated promptly and accurately on the basis of the image information obtained from a monocular vision camera mounted on the robot. Extracting the image feature points of the workpiece taken by the camera, a search region with a plurality of discrete space points is set on the basis of the estimated position and attitude of the camera. Then, the estimated image feature points of the workpiece, to be obtained when the workpiece is taken a view from these space points, are obtained. Then an error between the image feature point and the estimated feature point is calculated, and the position and attitude of the camera can be determined by finding the space point where the error is minimized.

Claims19

Dependent claims

A position and attitude recognition method for determining the position and attitude of an image pickup means with respect to an object having three-dimensional shape, the method comprising:

an image pickup step using the image pickup means for taking two-dimensional image information of the object;
an image processing step for extracting actual image feature representing the shape of an object, on the basis of said two-dimensional image information of said object taken by said image pickup means;
a search region setting step for setting a search region with a plurality of discrete space points having a required accuracy in discrete value and allocated in the vicinity of said image pickup means whose position and attitude are estimated based on external information;
perspective transformation equation calculating step for obtaining a perspective transformation equation for calculating two-dimensional estimated image feature of said object to be obtained when a view of said object is taken by said image pickup means located at each of said discrete space points of said search region, derived from the three-dimensional shape of said object;
an error calculating step for calculating an error between said actual image feature extracted by said image processing step and said estimated image feature calculated by said perspective transformation calculating step for each of said discrete space points;
and
a searching step for searching each of said discrete space points to find a space point which has a minimum error between said actual image feature and said estimated image feature, thereby determining the position and attitude of said image pickup means with respect to said object.

4 more elements

A position and attitude recognition apparatus for determining the position and attitude of image pickup means with respect to an object having three-dimensional shape, said apparatus comprising:

image pickup means for taking two-dimensional image information of the object having three-dimensional shape;
image processing means for extracting actual image feature representing the shape of an object, on the basis of said two-dimensional image information of said object taken by said image pickup means;
search region setting means for setting a search region with a plurality of discrete space points having a required accuracy in discrete value allocated in the vicinity of said image pickup means whose position and attitude are estimated based on external information;
perspective transformation equation calculating means for obtaining a perspective transformation equation for calculating two-dimensional image feature of said object to be obtained when a view of said object is taken by said image pickup means located at each of discrete space points of said search region, derived from the three-dimensional shape of said object;
perspective transformation calculating means for obtaining estimated image feature of said object to be obtained when view of said object is taken by said image pickup means located at each of said discrete space point of said search region, based on said perspective transformation equation;
error calculating means for calculating an error between said actual image feature extracted by said image processing means and said estimated image feature calculated by said perspective transformation calculating means for each of said discrete space points;
and
position and attitude determining means for searching each of said discrete space points to find a space point which has a minimum error between the actual image feature and the estimated image feature, thereby determining the position and attitude of said image pickup means with respect to said object.

5 more elements

Dependencies are inferred from the claim text.