3D Shape Measurement Using Phase and Defocus Data

The patent divides the measurement area into multiple local regions and performs phase unwrapping independently in each region. By segmenting the global phase unwrapping problem into smaller local problems, the method can handle abrupt shape changes and discontinuities more effectively, as each local region can be processed with continuity assumptions that are more likely to hold locally.

The patent introduces defocus amount as an additional measurement dimension alongside phase information. By combining phase data with defocus amount data, the system gains an extra degree of freedom for resolving phase ambiguities, enabling accurate measurement of objects with abrupt shape changes without relying solely on phase continuity.

The patent calculates defocus amounts selectively at specific sampling points rather than for all pixels or regions. By performing defocus calculation only where necessary (partial action), the system achieves sufficient measurement precision while significantly reducing the computational burden and number of required patterns, enabling real-time measurement capability.

The patent performs phase measurement first to obtain initial phase information, then uses this phase data to guide subsequent defocus amount calculations. By preparing phase information in advance, the system can focus defocus calculations only in regions where they are most needed, reducing overall measurement time while maintaining precision.

The patent segments the measurement area into multiple local regions and performs phase unwrapping independently in each region. This segmentation allows the method to handle discontinuous objects by treating each continuous local region separately, avoiding the phase continuity assumption failure that occurs in global unwrapping for discontinuous shapes.

The patent combines phase information with defocus amount information to create a multi-dimensional measurement approach. This additional dimension provides alternative pathways for phase unwrapping that do not rely solely on phase continuity, enabling successful measurement of discontinuous objects where traditional single-dimensional phase unwrapping fails.