Micrometer-level 3D measurement techniques in complex scenes based on stripe-structured light and photometric stereo

Area of Science:

• 3D Computer Vision
• Metrology
• Optical Measurement Systems

Background:

• Existing depth cameras like RGB-D, RealSense, and Kinect have limitations in complex object reconstruction.
• Stripe-based structured light (SL) offers potential for micrometer-level 3D measurement but struggles with surface texture, reflectivity, and occlusion.
• Photometric stereo (PS) alone also faces challenges in achieving high-resolution 3D reconstruction for complex geometries.

Purpose of the Study:

• To develop an advanced fusion strategy for micrometer-level 3D reconstruction of complex objects.
• To overcome inherent limitations of stripe-based SL systems using photometric stereo (PS).
• To enhance the robustness, accuracy, and resolution of 3D measurement for challenging surfaces.

Main Methods:

• Proposed a novel scene-adaptive decoding algorithm based on a binary tree to improve SL stripe detection robustness against noise and occlusion.
• Introduced a robust calibration method for area light sources in PS, leveraging absolute depth from SL.
• Developed a piecewise integration algorithm combining SL depth and PS normal information, using Gray code for subregion division.

Main Results:

• The fusion method effectively eliminates the impact of surface texture and high-reflectivity on reconstruction quality.
• Achieved camera-level resolution in 3D reconstruction, significantly improving upon existing micrometer-level measurement techniques.
• Experimental validation demonstrated micrometer-level accuracy and enhanced resolution on regular and complex objects, including those with surface textures.

Conclusions:

• The proposed fusion strategy significantly advances micrometer-level 3D measurement capabilities for complex objects.
• This integrated approach provides superior reconstruction quality compared to standalone SL or PS methods.
• The method offers a robust solution for high-precision 3D metrology in challenging scenarios.