US 12,013,229 B2
Three-dimensional shape measuring apparatus, three-dimensional shape measuring method, program, and storage medium
Shizuo Sakamoto, Tokyo (JP)
Assigned to NEC CORPORATION, Tokyo (JP)
Filed by NEC Corporation, Tokyo (JP)
Filed on Feb. 3, 2022, as Appl. No. 17/591,910.
Application 17/591,910 is a continuation of application No. 16/980,978, abandoned, previously published as PCT/JP2019/010414, filed on Mar. 13, 2019.
Prior Publication US 2022/0155057 A1, May 19, 2022
Int. Cl. G01B 11/25 (2006.01)
CPC G01B 11/2513 (2013.01) [G01B 11/254 (2013.01); G01B 11/2522 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A three-dimensional shape measuring method comprising:
projecting a first light pattern whose luminance changes at a first cycle on a measured object and acquiring an image of the measured object on which the first light pattern is projected;
projecting a second light pattern whose luminance changes at a second cycle that is longer than the first cycle on the measured object by a same projector device as that used for projection of the first light pattern and acquiring an image of the measured object on which the second light pattern is projected;
based on a luminance value at each of pixels of the image of the measured object on which the first light pattern is projected, calculating a relative phase value on each of parts of the measured object corresponding to each of the pixels;
based on a luminance value and the relative phase value at each of the pixels of the image of the measured object on which the second light pattern is projected, calculating an absolute phase value on each of the parts of the measured object corresponding to each of the pixels; and
based on the absolute phase value, calculating three-dimensional coordinates at each of the parts of the measured object corresponding to each of the pixels,
wherein the first light pattern is a sinusoidal pattern and the second light pattern is a luminance slope pattern whose luminance changes linearly,
wherein in acquiring the image of the measured object on which the first light pattern is projected, at least three images captured with different phases of the first light pattern projected on the measured object are acquired, and the at least three images are used to calculate the relative phase value, and
wherein in acquiring the image of the measured object on which the second light pattern is projected, only one image in which the measured object on which the second light pattern is projected is captured, and the only one image is used to calculate the absolute phase value.