Method and apparatus for multi-nodal, three-dimensional imaging
First Claim
Patent Images
1. A method for calibrating a three-dimensional imaging system the method comprising:
- providing first and second measurement units, the first measurement unit configured to acquire information from which locations of object features within a first measurement field can be determined in a first local coordinate system, the second measurement unit configured to acquire information from which locations of object features within a second measurement field can be determined in a second local coordinate system;
determining first locations in the first local coordinate system of a first plurality of calibration features located in the first measurement field, and, based on the first locations, determining locations in the first local coordinate system of a second plurality of calibration features located in the second measurement field;
determining locations of the second plurality of features in the second local coordinate system; and
, deriving a transformation between the local coordinate systems and a common coordinate system based upon the locations of the second plurality of calibration features in the first and second local coordinate systems.
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Abstract
A system for localizing objects has two or more measurement units. Calibration methods provide transformations to a common reference frame by locating calibration features in local reference frames of the measurement units. A calibration target spanning measurement fields of the measurement units may be used. The measurement units may have overlapping measurement fields. The measurement units may comprise stereo vision units or other units capable of locating objects or object features.
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Citations
55 Claims
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1. A method for calibrating a three-dimensional imaging system the method comprising:
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providing first and second measurement units, the first measurement unit configured to acquire information from which locations of object features within a first measurement field can be determined in a first local coordinate system, the second measurement unit configured to acquire information from which locations of object features within a second measurement field can be determined in a second local coordinate system;
determining first locations in the first local coordinate system of a first plurality of calibration features located in the first measurement field, and, based on the first locations, determining locations in the first local coordinate system of a second plurality of calibration features located in the second measurement field;
determining locations of the second plurality of features in the second local coordinate system; and
,deriving a transformation between the local coordinate systems and a common coordinate system based upon the locations of the second plurality of calibration features in the first and second local coordinate systems. - View Dependent Claims (2, 3, 4, 5)
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6. A method for calibrating a three-dimensional imaging system the method comprising:
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providing first and second measurement units, the first measurement unit configured to determine locations of object features within a first measurement field in a first local coordinate system, the second measurement unit configured to determine locations of object features within a second measurement field in a second local coordinate system, the first and second measurement fields overlapping within an overlap region;
determining locations of a plurality of calibration features located in the overlap region in each of the first and second local coordinate systems;
deriving a transformation between the local coordinate systems and a common coordinate system based upon the locations of the plurality of calibration features. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for calibrating a three-dimensional imaging system the method comprising:
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obtaining image data from a plurality of imaging devices of a first stereo measurement unit, the imaging devices having fields of view that overlap in a first stereo measurement field;
obtaining image data from a plurality of imaging devices of a second stereo measurement unit, the imaging devices having fields of view that overlap in a second stereo measurement field, the first and second stereo measurement fields overlapping one another in an overlap region containing at least one calibration target;
determining three-dimensional characteristics of at least one calibration target relative to the first stereo measurement unit using image data obtained from the imaging devices of the first stereo measurement unit;
determining three-dimensional characteristics of at least one calibration target relative to the second stereo measurement unit using image data obtained from the imaging devices of the second stereo measurement unit; and
,deriving calibration parameters from the three-dimensional characteristics of the calibration targets relative to the first and second stereo measurement units, the calibration parameters comprising information about a position and orientation of the first stereo measurement units relative to the second stereo measurement unit. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. Apparatus for determining the locations of object features in three dimensions, the apparatus comprising:
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a first measurement unit configured to generate first data from which locations of object features in a first measurement field can be determined in a first local coordinate system;
a second measurement unit configured to generate second data from which locations of object features in a second measurement field can be determined in a second local coordinate system; and
,a processor configured to;
receive the first and second data;
extract from the first data information about a first plurality of calibration features in the first measurement field; and
,based on the calibration information, determine locations in the first local coordinate system of a second plurality of calibration features in the second measurement field;
determine from the second data locations of the second plurality of calibration features in the second local coordinate system; and
, based on the locations of the second plurality of calibration features in the first and second local coordinate systems, generate a transformation which, when applied to the second data, expresses locations of object features in a common coordinate system. - View Dependent Claims (31, 32)
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33. Apparatus for determining the locations of object features in three dimensions, the apparatus comprising:
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a first measurement unit configured to generate first data from which locations of object features in a first measurement field can be determined in a first local coordinate system;
a second measurement unit configured to generate second data from which locations of object features in a second measurement field can be determined in a second local coordinate system, the second measurement unit located so that the first and second measurement fields overlap in an overlap region; and
,a processor configured to;
receive the first and second data;
extract from each of the first and second data calibration information about a plurality of calibration features of one or more calibration objects located in the overlap region; and
,based on the calibration information, generate a transformation which, when applied to the second data expresses locations of object features in a common coordinate system. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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41. Apparatus for determining the locations of object features in three dimensions, the apparatus comprising:
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a first stereo measurement unit comprising a plurality of imaging devices, the imaging devices having fields of view that overlap in a first stereo measurement field;
a second stereo measurement unit comprising a plurality of imaging devices, the imaging devices having fields of view that overlap in a second stereo measurement field, the first and second stereo measurement fields overlapping one another in an overlap region; and
,a processor, configured to;
receive image data from individual imaging devices in the fist and second stereo measurement units;
derive calibration parameters related to relative positions and orientations of the first and second stereo measurement units, such that image data received from the first and second stereo vision units may be transformed to a common reference coordinate system, using the calibration parameters, and, locate features of objects in the first or second stereo measurement field in a common coordinate system using the image data and the calibration parameters. - View Dependent Claims (42, 43)
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44. An apparatus for determining locations of object features, the apparatus comprising:
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means for obtaining first data representing locations of object features in a first measurement field in a first local coordinate system;
means for obtaining second data representing locations of object features in a second measurement field in a second local coordinate system;
means for locating in the first data a first plurality of calibration features in the first measurement field and determining based on the first plurality of calibration features, locations of a second plurality of calibration features in the second measurement field;
means for locating in the second data the plurality of calibration features;
means for determining calibration parameters based on the calibration features located in the first and second data; and
,means for locating object features relative to a common coordinate system using the calibration parameters. - View Dependent Claims (45, 46, 48, 49)
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47. The apparatus of clam 45 wherein the transformation functions are adapted to provide as outputs the locations of object features in a common coordinate system when the transformation functions are used in processing the first data or the second data or both the first and second data.
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50. Processing apparatus for use in determining locations of object features detected by one of a plurality of measurement in units, the processing apparatus comprising:
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an input for receiving first data from which locations of object features in a first measurement field can be determined in a first local coordinate system and second data from which locations of object features in a second measurement field can be determined in a second local coordinate system, the first and second measurement fields overlapping in an overlap region; and
,a processor configured to;
extract from each of the first and second data calibration information about a plurality of calibration features of one or more calibration objects located in the overlap region; and
,based on the calibration information, generate a transformation which, when applied to the second data expresses locations of object features in a common coordinate system.
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51. A machine readable medium carrying a set of instructions which, when executed by a data processor cause the data processor to perform a method for calibrating a three-dimensional imaging system, comprising;
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receiving first image data from a plurality of first imaging devices of a first measurement unit, the first imaging devices having fields of view that overlap in a first measurement field and second image data from a plurality of second imaging devices of a second measurement unit, the second imaging devices having fields of view that overlap in a second measurement field, the first and second stereo measurement fields overlapping one another in an overlap region;
locating a plurality of calibration features in each of the first and second image data;
determining, from the locations in the first and second data of the calibration features, information characterizing a position and orientation of the second stereo measurement unit relative to the first stereo measurement unit.
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52. A method of calibrating a three-dimensional imaging system comprising a plurality of measurement units each having a local coordinate system, the method comprising:
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a step for acquiring locations of a plurality of calibration features in a first local coordinate system of a first measurement unit;
a step for acquiring locations of the plurality of calibration features in each of one or more additional local coordinate systems; and
,a step for creating a transformation from one or more of the local coordinate systems to a common coordinate system based on the locations of the plurality of calibration features in the first local coordinate system and the locations of the plurality of calibration features in at least one of the one or more additional local coordinate systems.
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53. A method for calibrating a three-dimensional imaging system comprising:
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providing first and second measurement units, the first measurement unit configured to determine locations in a first local coordinate system of object features within a first measurement field, the second measurement unit configured to determine in a second local coordinate system locations of object features within a second measurement field;
determining locations of a first plurality of calibration features in the first local coordinate system, the first plurality of calibration features located in the first measurement field;
determining locations of a second plurality of calibration features in the second local coordinate system the second plurality of calibration features located in the second measurement field, first plurality of features having a fixed location relative to the second plurality of features; and
,deriving a transformation between the local coordinate systems and a common coordinate system based upon the locations of the first and second pluralities of calibration features. - View Dependent Claims (54, 55)
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Specification