Patent ID: 11900591
Assignee: CANON KABUSHIKI KAISHA
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 12:
13. A non-transitory computer-readable storage medium configured to store a computer program to control a displacement meter, the displacement meter comprising:
an incoherent light source configured to illuminate an object to be measured;
a double telecentric optical system configured to receive diffused-reflected light generated on a surface of the object that has been illuminated by the incoherent light source;
an image pickup unit configured to receive diffused-reflected light through the double telecentric optical system to output an image; and
at least one processor or circuit configured to function as:
a calculation unit configured to calculate the displacement of the object to be measured,
wherein the computer program comprises instructions for causing the calculation unit to execute following processes:
calculating a displacement amount of the object to be measured by using sub-pixel estimation and using a cross-correlation function between reference image data and measurement image data, in which an image acquired during a predetermined timing from an imaging unit serves as the reference image data and an image acquired after the predetermined timing serves as the measurement image data,
generating a value obtained by adding a correction value to the displacement amount to serve as a correction displacement amount,
setting the most recent measurement image data as the reference image data and setting the displacement amount obtained most recently as the correction value in a case where the displacement amount meets a predetermined condition, and
inhibiting changing the reference image data and the correction value in a case where the displacement amount does not meet the predetermined condition.