Three-dimensional reconstruction from a fringe projection system through a planar transparent medium

Area of Science:

• Optical metrology
• Computer vision
• 3D reconstruction

Background:

• Vision measurement systems in protective transparent covers are prone to significant errors.
• Light ray deflection at the transparent medium's surfaces deviates imaging positions.
• Traditional triangulation-based methods fail to account for refractive distortions.

Purpose of the Study:

• To develop an accurate three-dimensional (3D) reconstruction method for objects viewed through a planar transparent medium.
• To address and correct for measurement errors caused by light refraction.
• To enable unbiased 3D shape measurement in environments with protective transparent covers.

Main Methods:

• Derivation of coordinate transformation based on Snell's law for light refraction through a planar medium.
• Development of a modified fringe projection technique incorporating refractive error correction.
• Experimental validation using 3D shape measurement of a white plate and a spherical object.

Main Results:

• The proposed method accurately reconstructs the 3D shape of objects despite light refraction.
• Experimental results demonstrate a significant reduction in measurement errors compared to traditional methods.
• The effectiveness of the modified fringe projection technique was validated.

Conclusions:

• The developed method provides an unbiased approach for 3D reconstruction through transparent media.
• This technique enhances the accuracy of vision measurement systems in protected environments.
• The study offers a practical solution for precise 3D metrology in challenging conditions.