Three-dimensional displacement measuring method and three-dimensional displacement measuring device
A three-dimensional displacement measuring method includes: calculating camera parameters of N cameras based on M correction images shot at M viewpoints by cameras including the N cameras, where N is an integer greater than 1 and M is an integer greater than N, the M viewpoints being mutually different; and measuring a displacement over time of a subject caused by vibration of the subject in a three-dimensional space, based on (1) sets of N images and (2) the camera parameters. The N images in each of the sets are generated by the N cameras shooting the subject at the same time, and the sets are generated at different times. The different times are set according to a frequency of the vibration of the subject.
1 . A three-dimensional displacement measuring method comprising:
calculating camera parameters of N cameras based on M correction images shot at M viewpoints by cameras including the N cameras, the M viewpoints being mutually different; and
measuring a displacement over time of a subject caused by vibration of the subject in a three-dimensional space, based on (1) sets of N images shot at N viewpoints and (2) the camera parameters, wherein
N is an integer greater than 1, and M is an integer greater than N,
the N images in each of the sets are generated by the N cameras shooting the subject at a same time, and the sets are generated at different times,
the different times are set according to a frequency of the vibration of the subject, and
the M viewpoints used in the calculating of the camera parameters include all of the N viewpoints corresponding to arrangement positions of the N cameras used in the measuring of the displacement, and further include at least one additional viewpoint that is not used in the measuring of the displacement.
2 . The three-dimensional displacement measuring method according to claim 1 , wherein
the frequency of the vibration is a resonance frequency of the subject.
3 . The three-dimensional displacement measuring method according to claim 2 , wherein
the different times include at least three different times for each time period represented by a reciprocal of the resonance frequency.
4 . The three-dimensional displacement measuring method according to claim 1 , wherein
the measuring of the displacement includes:
calculating three-dimensional points each of which is a three-dimensional point corresponding to a different one of the different times, by performing, on each of the sets of N images:
(i) calculating a first corresponding point of the subject and a second corresponding point which corresponds to the first corresponding point, the first corresponding point being included in a first image included in the N images, the second corresponding point being included in a second image included in the N images; and
(ii) calculating a three-dimensional point of the subject in the three-dimensional space, based on the camera parameters, the first corresponding point, and the second corresponding point; and
calculating a displacement over time of the three-dimensional point, from the three-dimensional points.
5 . The three-dimensional displacement measuring method according to claim 1 , wherein
N is determined based on the camera parameters and an accuracy of the measuring of the displacement.
6 . The three-dimensional displacement measuring method according to claim 1 , wherein
the N cameras include a first camera and a second camera which are disposed next to each other,
the M viewpoints include a first midpoint between a first position at which the first camera is disposed and a second position at which the second camera is disposed, and
when a midpoint between the first position and the first midpoint is designated as a second midpoint, more viewpoints among the M viewpoints are provided between the second midpoint and the first position than between the first midpoint and the second midpoint.
7 . The three-dimensional displacement measuring method according to claim 6 , wherein
in the calculating of the camera parameters, no viewpoint is provided between the first midpoint and the second midpoint.
8 . The three-dimensional displacement measuring method according to claim 1 , wherein
the N cameras include a non-fixed camera.
9 . A three-dimensional displacement measuring device comprising:
memory; and
a processor coupled to the memory and configured to:
calculate camera parameters of N cameras based on M correction images shot at M viewpoints by cameras including the N cameras, the M viewpoints being mutually different; and
measure a displacement over time of a subject caused by vibration of the subject in a three-dimensional space, based on (1) sets of N images shot at N viewpoints and (2) the camera parameters, wherein
N is an integer greater than 1, and M is an integer greater than N,
the N images in each of the sets are generated by the N cameras shooting the subject at a same time, and the sets are generated at different times,
the different times are set according to a frequency of the vibration of the subject, and
the M viewpoints used in the calculating of the camera parameters include all of the N viewpoints corresponding to arrangement positions of the N cameras used in the measuring of the displacement, and further include at least one additional viewpoint that is not used in the measuring of the displacement.