Unwrapping of Digital Speckle-Pattern Interferometry Phase Maps by use of a Minimum L(0)-Norm Algorithm

Area of Science:

• Optical Metrology
• Image Processing
• Interferometry

Background:

• Digital speckle-pattern interferometry (DSPI) generates wrapped phase maps.
• Phase unwrapping is crucial for quantitative analysis of DSPI data.
• Existing algorithms face challenges with complex phase map features.

Purpose of the Study:

• To investigate the performance of a minimum L(0)-norm unwrapping algorithm.
• To analyze the algorithm's handling of common DSPI artifacts.
• To propose a novel solution for complex phase unwrapping scenarios.

Main Methods:

• Utilized synthetic DSPI wrapped phase maps simulating experimental data.
• Evaluated a minimum L(0)-norm algorithm with automatic pixel masking.
• Analyzed performance against features like shears, speckle noise, fringe cuts, and object limits.

Main Results:

• The minimum L(0)-norm algorithm effectively masks inconsistent pixels.
• Shears, speckle noise, fringe cuts, and object limits were analyzed.
• The algorithm alone cannot satisfactorily unwrap complex phase maps with coexisting shears and fringe cuts.

Conclusions:

• The minimum L(0)-norm algorithm shows limitations in handling complex DSPI phase maps.
• A new scheme is proposed to overcome the limitations of the current algorithm.
• Further research is needed to refine phase unwrapping techniques for challenging DSPI data.