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US 8,878,905 B2Granted
Focus scanning apparatus
Assignee3Shape A/S
InventorsRune Fisker, Henrik Öjelund, Rasmus Kjær, Mike van der Poel, Arish A. Qazi, Karl-Josef Hollenbeck
Life of this patent
Estimating the term…
Abstract
Disclosed is a handheld scanner for obtaining and/or measuring the 3D geometry of at least a part of the surface of an object using confocal pattern projection techniques. Specific embodiments are given for intraoral scanning and scanning of the interior part of a human ear.
Claims36
A scanner for obtaining and/or measuring the 3D geometry of at least a part of the surface of an object, said scanner comprising:
- at least one camera accommodating an array of sensor elements, a light source for generating a probe light incorporating a spatial pattern, an optical system for transmitting the probe light towards the object thereby illuminating at least a part of the object with said spatial pattern in one or more configurations and for transmitting at least a part of the light returned from the object to the camera, a focus element within the optical system for varying a position of a focus plane of the spatial pattern on the object, an obtaining unit for obtaining at least one image from said array of sensor elements, an evaluating unit for evaluating a correlation measure at each focus plane position between at least one image pixel and a weight function, where the weight function is determined based on information of the configuration of the spatial pattern, wherein the correlation measure is calculated as a dot product computed for each of a plurality of said focus plane positions;
- a data processor for:
- determining by analysis of the correlation measure the in-focus position(s) of:
- each of a plurality of image pixels for a range of focus plane positions, or each of a plurality of groups of image pixels for a range of focus plane positions, and transforming in-focus data into 3D real world coordinates.
1 more element
A method for obtaining and/or measuring the 3D geometry of at least a part of the surface of an object, said method comprising the steps of:
- generating a probe light incorporating a spatial pattern, transmitting the probe light towards the object along the optical axis of an optical system, thereby illuminating at least a part of the object with said spatial pattern, transmitting at least a part of the light returned from the object to the camera, varying the position of the focus plane of the pattern on the object while maintaining a fixed spatial relation of the scanner and the object, obtaining at least one image from said array of sensor elements, evaluating a correlation measure at each focus plane position between at least one image pixel and a weight function, where the weight function is determined based on information of the configuration of the spatial pattern, wherein the correlation measure is calculated as a dot product computed for each of a plurality of said focus plane positions;
- determining by analysis of the correlation measure the in-focus position(s) of:
- each of a plurality of image pixels in the camera for said range of focus plane positions, or each of a plurality of groups of image pixels in the camera for said range of focus planes, and transforming in-focus data into 3D real world coordinates.
Dependencies are inferred from the claim text.