Image measurement apparatus, image measurement method and image measurement program
AssigneeCanon Kabushiki Kaisha
InventorKota Tani
Life of this patent
Estimating the term…
Abstract
Two-dimensional measurement is allowed with a small error even in the case where a difference occurs between a measurement plane for a workpiece and a plane with calibrated external parameters. When the workpiece 2 is gripped by a holding device 3, an image measurement apparatus 1 calculates the difference between the calibration plane 17 where the external parameters are calibrated and the measurement plane 20 for the workpiece 2. The image measurement apparatus 1 corrects the external parameters such that the calibration plane 17 coincides with the measurement plane 20, and two-dimensionally measures the workpiece 2 using the corrected external parameters.
Claims7
An image measurement apparatus, comprising:
- a first camera that takes an image of a workpiece held by a holding device;
- a detecting device that detects a position and/or a posture of a measurement plane for the workpiece held by the holding device;
- and
- a control unit that stores external parameters of the first camera and a position and/or a posture of a calibration plane where the external parameters are calibrated, corrects the external parameters based on a detected value by the detecting device such that the positions and/or the postures of the measurement plane and the calibration plane coincide with each other, and measures a two-dimensional position and/or a posture of the workpiece from the image taken by the first camera using the corrected external parameters.
An image measurement method of causing a camera whose external parameters are calibrated, to take an image of a workpiece held by a holding device, and measuring a two-dimensional position and/or a posture of the workpiece based on the taken image, the method comprising causing a calculating device to:
- calculate a difference between a calibration plane where the external parameters are calibrated and a measurement plane for the workpiece;
- correct the external parameters based on the difference calculated by the difference calculating such that positions and/or postures of the measurement plane and the calibration plane coincide with each other;
- and
- two-dimensionally measure a two-dimensional position and/or posture of the workpiece from the image taken by the camera using the external parameters corrected by the correcting of the external parameters.
Dependencies are inferred from the claim text.