Generic gamma correction for accuracy enhancement in fringe-projection profilometry

Area of Science:

• Optical Metrology
• 3D Imaging
• Computer Vision

Background:

• Fringe-projection profilometry is a key noncontact 3D shape acquisition technique.
• Luminance nonlinearity from gamma effects in digital projectors and cameras degrades measurement accuracy.
• Existing methods struggle to effectively compensate for these intensity variations.

Purpose of the Study:

• To develop a robust and simple scheme for eliminating intensity nonlinearity caused by the gamma effect in fringe-projection profilometry.
• To enhance the accuracy of 3D shape measurements obtained via fringe-projection profilometry.
• To provide a practical solution for improving the reliability of 3D scanning systems.

Main Methods:

• Combining a universal phase-shifting algorithm with a gamma correction method.
• Utilizing three-step and large-step phase-shifting techniques to detect the system's gamma value.
• Implementing a gamma pre-encoding process before actual 3D shape measurements.

Main Results:

• Successfully eliminated intensity nonlinearity induced by the gamma effect.
• Achieved high measurement accuracy using conventional small-step phase-shifting algorithms.
• Experimental verification confirmed the technique's validity and effectiveness.

Conclusions:

• The proposed gamma correction scheme significantly improves the accuracy of fringe-projection profilometry.
• This method offers a practical and effective solution for mitigating gamma-induced errors in 3D shape measurements.
• The technique enables more reliable and precise 3D object reconstruction.