Abstract: A measurement apparatus includes a laser apparatus, a branching part that branches a frequency-modulated laser beam output by the laser apparatus into a reference light and a measurement light; a beat signal generation part that generates a beat signal by mixing a reflected light and the reference light, a conversion part that converts the beat signal into a digital signal at a first sampling rate and frequency-analyses it, an extraction part that extracts a signal component corresponding to a cavity frequency from the frequency-modulated laser beam, a digital filter that digitally filters the extracted signal component at a second sampling rate; and a calculation part that calculates a difference in a propagation distance between the reference light and the measurement light.

Abstract: A calibration method includes: measuring, with a CMM, a ball-to-ball distance of a plurality of edges of an inspection gauge installed in a first posture, a second posture and a third posture, and calculating a calibration value calibrating a ball-to-ball distance between two balls at respective ends of a plurality of edges of the inspection gauge by solving simultaneous equations including the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the first posture, the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the second posture, the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the third posture, and a measurement error of the CMM at the measurement position.

Abstract: A three-dimensional-measuring-apparatus inspection gauge includes a plurality of targets to be measured with which a tip of a probe of a three-dimensional measuring apparatus comes into contact; and a frame member that supports the plurality of targets. The plurality of targets are arranged in positions corresponding to each vertex of a triangular prism.

Abstract: A measurement point determination method for determining the number or an arrangement of measurement points for a measurement apparatus that performs measurement processing of a measurement item at a plurality of measurement points, the method comprises the steps of acquiring a minimum value and a maximum value of the number of measurement points, acquiring a target value of uncertainty for the measurement item of the measurement apparatus, estimating uncertainties when the measurement item is measured by the measurement apparatus using two or more of the numbers of measurement points between the minimum value and the maximum value of the number of measurement points, and determining the number of measurement points of the measurement apparatus on the basis of the target value and the estimated uncertainties.

Abstract: A calibration method includes the steps of placing a structure to be measured at a first position, measuring a first distance from a laser interferometer to a reflector, and measuring first coordinates of a body to be measured, moving the structure to be measured to a second position, measuring a second distance from the laser interferometer to the reflector and measuring second coordinates of the structure to be measured with the coordinate measuring apparats, while the structure to be measured is at the second position, determining a scale error of the reference instrument, mounting the reference instrument, measuring the interval between objects to be measured, and calculating a calibration value of the interval between the objects to be measured.

Abstract: A calibration method includes: measuring, with a CMM, a ball-to-ball distance of a plurality of edges of an inspection gauge installed in a first posture, a second posture and a third posture, and calculating a calibration value calibrating a ball-to-ball distance between two balls at respective ends of a plurality of edges of the inspection gauge by solving simultaneous equations including the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the first posture, the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the second posture, the ball-to-ball distance of the plurality of edges of the inspection gauge installed in the third posture, and a measurement error of the CMM at the measurement position.

Abstract: A spatial accuracy correction apparatus performs a spatial accuracy correction of a positioner displacing a displacer to a predetermined set of spatial coordinates using a measurable length value measured by an interferometer and a measurable value of the set of spatial coordinates of the displacement body that is measured by the positioner. The measured length value and the measured value for each measurement point are acquired by displacing the displacement body to a plurality of measurement points in order, one or more repeated measurements are conducted for at least one of the plurality of measurement points being measured after conducting measurement of the measured length value and the measured value for each of the plurality of measurement points, and the plurality of points are measured again when a repeat error of the measured length value is equal to or greater than a threshold value.

Abstract: A method that corrects an error in positioning in a positioning mechanism by using a measurable length value measured by a laser interferometer and a measured value for spatial coordinates measured by the positioning mechanism. The method includes a measurement step in which a retroreflector affixed to a displacer is displaced to a plurality of measurement points, and the measured length value and the measured value at each of the measurement points is acquired; and a parameter calculation step in which a correction parameter is calculated based on the measured value, the measured length value, and the coordinates of a rotation center of the tracking-type laser interferometer. A first correction constant is applied to the measured length value for each measurement line, and a second correction constant different from the first correction constant is applied to the coordinates of the rotation center of the interferometer for each measurement line.

Abstract: An inspection method, correction method, and inspection device that include measuring a first spatial position where laser light is emitted at a first region and measuring a first strike position where the inspection device is struck by the laser light in the first region, the measurements being performed by emitting the laser light at the first region of the inspection device; measuring a second spatial position where the laser light is emitted at a second region and measuring a second strike position where the inspection device is struck by the laser light in the second region, the measurements being performed by emitting the laser light at the second region of the inspection device; and comparing measurement results for the first spatial position and the second spatial position with measurement results for the first strike position and the second strike position.

Abstract: A calibration method includes the steps of placing a structure to be measured at a first position, measuring a first distance from a laser interferometer to a reflector, and measuring first coordinates of a body to be measured, moving the structure to be measured to a second position, measuring a second distance from the laser interferometer to the reflector and measuring second coordinates of the structure to be measured with the coordinate measuring apparats, while the structure to be measured is at the second position, determining a scale error of the reference instrument, mounting the reference instrument, measuring the interval between objects to be measured, and calculating a calibration value of the interval between the objects to be measured.

Abstract: An inspection method, correction method, and inspection device that include measuring a first spatial position where laser light is emitted at a first region and measuring a first strike position where the inspection device is struck by the laser light in the first region, the measurements being performed by emitting the laser light at the first region of the inspection device; measuring a second spatial position where the laser light is emitted at a second region and measuring a second strike position where the inspection device is struck by the laser light in the second region, the measurements being performed by emitting the laser light at the second region of the inspection device; and comparing measurement results for the first spatial position and the second spatial position with measurement results for the first strike position and the second strike position.

Abstract: A measurement apparatus includes a laser apparatus, a branching part that branches a frequency-modulated laser beam output by the laser apparatus into a reference light and a measurement light; a beat signal generation part that generates a beat signal by mixing a reflected light and the reference light, a conversion part that converts the beat signal into a digital signal at a first sampling rate and frequency-analyses it, an extraction part that extracts a signal component corresponding to a cavity frequency from the frequency-modulated laser beam, a digital filter that digitally filters the extracted signal component at a second sampling rate; and a calculation part that calculates a difference in a propagation distance between the reference light and the measurement light.

Abstract: A measurement point determination method for determining the number or an arrangement of measurement points for a measurement apparatus that performs measurement processing of a measurement item at a plurality of measurement points, the method comprises the steps of acquiring a minimum value and a maximum value of the number of measurement points, acquiring a target value of uncertainty for the measurement item of the measurement apparatus, estimating uncertainties when the measurement item is measured by the measurement apparatus using two or more of the numbers of measurement points between the minimum value and the maximum value of the number of measurement points, and determining the number of measurement points of the measurement apparatus on the basis of the target value and the estimated uncertainties.

Abstract: To inspect a positioning machine by a laser tracking interferometer that tracks a retroreflector using a laser beam, the positioning accuracy of the positioning machine is evaluated by comparing a distance ?dij,C with a distance ?dij,L measured by the laser tracking interferometer, the distance ?dij,C being acquired by orthogonal projection of the position vectors of measurement points pi and pj measured by the positioning machine to the straight line gk passing through the rotation center M of the laser tracking interferometer.

Abstract: A method that corrects an error in positioning in a positioning mechanism by using a measurable length value measured by a laser interferometer and a measured value for spatial coordinates measured by the positioning mechanism. The method includes a measurement step in which a retroreflector affixed to a displacer is displaced to a plurality of measurement points, and the measured length value and the measured value at each of the measurement points is acquired; and a parameter calculation step in which a correction parameter is calculated based on the measured value, the measured length value, and the coordinates of a rotation center of the tracking-type laser interferometer. A first correction constant is applied to the measured length value for each measurement line, and a second correction constant different from the first correction constant is applied to the coordinates of the rotation center of the interferometer for each measurement line.

Abstract: A spatial accuracy correction apparatus performs a spatial accuracy correction of a positioner displacing a displacer to a predetermined set of spatial coordinates using a measurable length value measured by an interferometer and a measurable value of the set of spatial coordinates of the displacement body that is measured by the positioner. The measured length value and the measured value for each measurement point are acquired by displacing the displacement body to a plurality of measurement points in order, one or more repeated measurements are conducted for at least one of the plurality of measurement points being measured after conducting measurement of the measured length value and the measured value for each of the plurality of measurement points, and the plurality of points are measured again when a repeat error of the measured length value is equal to or greater than a threshold value.

Abstract: To inspect a positioning machine by a laser tracking interferometer that tracks a retroreflector using a laser beam, the positioning accuracy of the positioning machine is evaluated by comparing a distance ?dij,C with a distance ?dij,L measured by the laser tracking interferometer, the distance ?dij,C being acquired by orthogonal projection of the position vectors of measurement points pi and pj measured by the positioning machine to the straight line gk passing through the rotation center M of the laser tracking interferometer.

Abstract: An index error estimating apparatus used for an index error calibrating apparatus that has a grating disk supported by a rotation shaft and four detectors arranged on the grating disk. The index error estimating apparatus includes a detected value synthesizer that calculates a linear sum by multiplying by a predetermined coefficient each of detected values obtained from each of the at least four detectors; and a Fourier component identifier that uses a Fourier component of the linear sum and identifies a Fourier component of the index error.

Abstract: A laser tracking interferometer has a carriage provided with a first displacement gauge outputting a displacement signal associated with a relative displacement from a reference sphere; a second retroreflector provided to the carriage; a laser interferometer provided to the carriage and outputting a displacement signal associated with a relative displacement between the first retroreflector and the second retroreflector; and a data processor calculating a displacement of the first retroreflector with reference to the reference sphere based on the displacement signal output from the first displacement gauge and the displacement signal output from the laser interferometer.

Abstract: A laser tracking interferometer has a carriage provided with a first displacement gauge outputting a displacement signal associated with a relative displacement from a reference sphere; a second retroreflector provided to the carriage; a laser interferometer provided to the carriage and outputting a displacement signal associated with a relative displacement between the first retroreflector and the second retroreflector; and a data processor calculating a displacement of the first retroreflector with reference to the reference sphere based on the displacement signal output from the first displacement gauge and the displacement signal output from the laser interferometer.