Absolute phase measurements using geometric constraints between multiple cameras and projectors

Rui Ishiyama, Shizuo Sakamoto, Johji Tajima, Takayuki Okatani, Koichiro Deguchi

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


The method of phase shift with the projection of multiple cyclic patterns enables 3D measurement that is highly accurate, dense, and fast. However, this measurement is only possible for the wrapped phase value, which has ambiguities in its multiples of cycles. Two particular problems are that conventional methods require additional patterns to be projected to determine the absolute phase and that unwrapping the phase tends to fail where depth varies abruptly. Two methods are proposed: the first is to determine the absolute phase without additional patterns being projected by observing the projected pattern with multiple cameras and applying the geometric constraints between them, and the second is to prevent failure in unwrapping the phase by referring to continuities in the relative phases of multiple projected patterns. The proposed methods were achieved with a 3D scanner that can measure approximately a 180° field of view within 0.5 s, with an accuracy of 0.14 mm in depth.

Original languageEnglish
Pages (from-to)3528-3539
Number of pages12
JournalApplied optics
Issue number17
Publication statusPublished - 2007 Jun 10

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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