Machine vision system for analyzing features based on multiple object images

A machine vision method for producing a representation of a selected feature plane of an object in a physical coordinate system of the object, the method comprising:

• acquiring a plurality of perspective-view images of the object that each correspond to a perspective view of a distinct orientation of the object about a selected object axis;
• identifying, in at least one acquired perspective-view image, feature points in the selected feature plane as-projected into that acquired image;
• mapping feature points from the perspective-view image projection to the selected feature plane in the physical coordinate system of the object;
• and
• correlating feature points from at least one acquired image with physical orientations on the selected feature plane in the physical coordinate system of the object, based on the object orientation corresponding to that acquired image;
• and wherein acquiring a plurality of object images comprises acquiring a sequence of object images, and wherein correlating feature points comprises correlating feature points to a physical orientation on the selected feature plane based on order position of that image in the sequence of images and based on difference in object orientation between adjacent images in the sequence.

A machine vision method for producing a representation of a selected feature plane of an object, in a physical coordinate system of the object, as the object rotates about an axis of rotation that is perpendicular to the selected feature plane, the method comprising:

• acquiring a sequence of perspective-view object images from a fixed viewing location as the object rotates about the axis of rotation, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the object about the axis of object rotation;
• identifying, in at least one acquired perspective-view image, feature points in the selected feature plane as-projected into that acquired image;
• mapping feature points from the perspective-view image projection to the selected feature plane in the physical coordinate system of the object;
• and
• correlating feature points from at least one acquired image with physical orientations on the selected feature plane in the physical coordinate system of the object, based on the distinct angular object orientation between adjacent images in the sequence and order position of that acquired image in the image sequence.

A machine vision method for analyzing a representation of a semiconductor melt surface from which a semiconductor crystal ingot is vertically pulled, in a physical coordinate system of the ingot, as the ingot is rotated in a first direction about a vertical axis of rotation and the melt is rotated in a second direction about the vertical axis of rotation, the method comprising:

• acquiring a sequence of perspective-view images of the melt surface from a fixed viewing location, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the ingot and the melt surface about the axis of rotation;
• identifying, in at least one acquired perspective-view image, feature points in the melt surface as-projected into that image;
• mapping identified feature points from the perspective-view image projection to the melt surface in the physical coordinate system of the ingot;
• correlating mapped melt feature points from at least one acquired image with physical orientations on the melt surface in the physical coordinate system of the ingot, based on the distinct angular orientation corresponding to that acquired image and order position of that acquired image in the image sequence;
• and
• analyzing the the melt surface features for a prespecified feature configuration.

A machine vision method for analyzing a representation of a selected cross-sectional circumferential contour of an object, in a physical coordinate system of the object, as the object rotates about an axis of rotation, the method comprising:

• acquiring a sequence of perspective-view object images from a fixed viewing location as the object rotates about the axis of rotation, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the object about the axis of object rotation;
• identifying, in at least one acquired perspective-view image, circumferential contour points in a feature plane corresponding to the selected cross-sectional circumferential contour and as-projected into that acquired image;
• mapping circumferential contour points from the perspective-view image projection to the selected circumferential contour in the physical coordinate system of the object;
• correlating circumferential contour points from at least one acquired image with physical locations around the circumferential contour in the physical coordinate system of the object, based on the distinct angular object orientation corresponding to that acquired image and order position of that acquired image in the image sequence;
• and
• analyzing the correlated circumferential contour points based on an expected configuration of features along the contour.

A machine vision method for analyzing representation of a cross-sectional meniscus contour produced by a semiconductor ingot on a semiconductor melt surface, in a physical coordinate system of the ingot, as the ingot is vertically pulled out of the melt surface and the ingot and melt are rotated in opposite directions about a common vertical axis of rotation, the method comprising:

• acquiring a sequence of perspective-view images of the ingot and melt from a fixed viewing location, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the ingot and melt surface about the axis of rotation;
• identifying, in at least one acquired perspective-view image, meniscus contour points as-projected into that acquired image;
• mapping identified meniscus contour points from the perspective-view image projection to the meniscus contour in the physical coordinate system of the ingot;
• correlating mapped meniscus contour points from at least one acquired image with physical orientations around the meniscus in the physical coordinate system of the ingot, based on the distinct angular orientation corresponding to that image and order position of that image in the image sequence;
• and
• analyzing the correlated meniscus contour points to determine if a fault condition has occurred.

A machine vision system for producing a representation of a selected feature plane of an object in a physical coordinate system of the object, the system comprising:

• means for acquiring a plurality of images of the object that each correspond to a distinct orientation of the object about a selected object axis;
• means for identifying, in at least one acquired image, feature points in the selected feature plane as-projected into that acquired image;
• means for associating feature points with the selected feature plane in the physical coordinate system of the object;
• and
• means for correlating feature points from at least one acquired image with physical orientations on the selected feature plane in a physical coordinate system of the object, based on the object orientation corresponding to that acquired image;
• and wherein acquiring a plurality of object images comprises acquiring a sequence of object images, and wherein correlating feature points comprises correlating feature points to a physical orientation on the selected feature plane based on order position of that image in the sequence of images and based on difference in object orientation between adjacent images in the sequence.

A machine vision system for producing a representation of a selected feature plane of an object in a physical coordinate system of the object, the system comprising:

• means for acquiring a plurality of perspective-view images of the object that each correspond to a perspective view of a distinct orientation of the object about a selected object axis;
• means for identifying, in at least one acquired perspective-view image, feature points in the selected feature plane as-projected into that acquired image;
• means for mapping feature points from the perspective-view image projection to the selected feature plane in the physical coordinate system of the object;
• and
• means for correlating feature points from at least one acquired image with physical orientations on the selected feature plane in the physical coordinate system of the object, based on the object orientation corresponding to that acquired image;
• and wherein acquiring a plurality of object images comprises acquiring a sequence of object images, and wherein correlating feature points comprises correlating feature points to a physical orientation on the selected feature plane based on order position of that image in the sequence of images and based on difference in object orientation between adjacent images in the sequence.

A machine vision system for producing a representation of a selected feature plane of an object, in a physical coordinate system of the object, as the object rotates about an axis of rotation that is perpendicular to the selected feature plane, the system comprising:

• means for acquiring a sequence of perspective-view object images from a fixed viewing location as the object rotates about the axis of rotation, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the object about the axis of object rotation;
• means for identifying, in at least one acquired perspective-view image, feature points in the selected feature plane as-projected into that acquired image;
• means for mapping feature points from the perspective-view image projection to the selected feature plane in the physical coordinate system of the object;
• and
• means for correlating feature points from at least one acquired image with physical orientations on the selected feature plane in the physical coordinate system of the object, based on the distinct angular object orientation between adjacent imges in the sequene and order position of that acquired image in the image sequence.

A machine vision system for analyzing a representation of a semiconductor melt surface from which a semiconductor crystal ingot is vertically pulled, in a physical coordinate system of the ingot, as the ingot is rotated in a first direction about a vertical axis of rotation and the melt is rotated in a second direction about the vertical axis of rotation, the system comprising:

• means for acquiring a sequence of perspective-view images of the melt surface from a fixed viewing location, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the ingot and the melt surface about the axis of rotation;
• means for identifying, in at least one acquired perspective-view image, feature points in the melt surface as-projected into that image;
• means for mapping identified feature points from the perspective-view image projection to the melt surface in the physical coordinate system of the ingot;
• means for correlating mapped melt feature points from at least one acquired image with physical orientations on the melt surface in the physical coordinate system of the ingot, based on the distinct angular orientation corresponding to that acquired image and order position of that acquired image in the image sequence;
• and
• means for analyzing the the melt surface features for a prespecified feature configuration.

A machine vision system for analyzing a representation of a selected cross-sectional circumferential contour of an object, in a physical coordinate system of the object, as the object rotates about an axis of rotation, the system comprising:

• means for acquiring a sequence of perspective-view object images from a fixed viewing location as the object rotates about the axis of rotation, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the object about the axis of object rotation;
• means for identifying, in at least one acquired perspective-view image, circumferential contour points in a feature plane corresponding to the selected cross-sectional circumferential contour and as-projected into that acquired image;
• means for mapping circumferential contour points from the perspective-view image projection to the selected circumferential contour in the physical coordinate system of the object;
• means for correlating circumferential contour points from at least one acquired image with physical locations around the circumferential contour in the physical coordinate system of the object, based on the distinct angular object orientation corresponding to that acquired image and order position of that acquired image in the image sequence;
• and
• means for analyzing the correlated circumferential contour points based on an expected configuration of features along the contour.

A machine vision system for analyzing a representation of a cross-sectional meniscus contour produced by a semiconductor ingot on a semiconductor melt surface, in a physical coordinate system of the ingot, as the ingot is vertically pulled out of the melt surface and the ingot and melt are rotated in opposite directions about a common vertical axis of rotation, the system comprising:

• means for acquiring a sequence of perspective-view images of the ingot and melt from a fixed viewing location, each perspective-view image corresponding to a perspective view of a distinct angular orientation of the ingot and melt surface about the axis of rotation;
• means for identifying, in at least one acquired perspective-view image, meniscus contour points as-projected into that acquired image;
• means for mapping identified meniscus contour points from the perspective-view image projection to the meniscus contour in the physical coordinate system of the ingot;
• means for correlating mapped meniscus contour points from at least one acquired image with physical orientations around the meniscus in the physical coordinate system of the ingot, based on the distinct angular orientation corresponding to that image and order position of that image in the image sequence;
• and
• means for analyzing the correlated meniscus contour points to determine if a fault condition has occurred.