Structured light 3D in the presence of Global Illumination

The goal of this work is to build an end-to-end system for structured light 3D scanning under a broad range of global illumination effects, such as inter-reflections, diffusion and sub-surface scattering. We have designed structured light patterns that are resilient to individual global illumination effects using simple logical operations and tools from combinatorial mathematics. Scenes exhibiting multiple phenomena are handled by combining results from a small ensemble of such patterns. Our methods can be readily incorporated into existing scanning systems without a significant overhead in terms of capture time or hardware.
Depth Map (Our Technique)
3D Visualization
Previous Technique
Conventional Gray Codes
Modulated Phase Shifting
The scene shown above has significant global illumination in the form of interreflections and sub-surface scattering. Conventional Gray codes and phase-shifting result in errors at points receiving inter-reflections. Modulated phase-shifting produces errors on translucent fruits. In contrast, the depth map computed using our techniques is nearly error free. Please see the compilation of results below for more examples.


"Structured Light 3D Scanning in the Presence of Global Illumination"
Mohit Gupta, Amit Agrawal, Ashok Veeraraghavan, Srinivasa G. Narasimhan,
IEEE Computer Vision and Pattern Recognition (CVPR),
June, 2011.

"A Practical Approach to 3D Scanning in the Presence of Interre.ections, Subsurface Scattering and Defocus"
Mohit Gupta, Amit Agrawal, Ashok Veeraraghavan and Srinivasa G. Narasimhan
International Journal of Computer Vision (IJCV),

IJCV 2012
CVPR 2011
Presentation with Results

Gallery of Results

Illustration of our techniques on simple shapes:

Scenes with multiple global illumination effects:

Translucent objects (sub-surface scattering and diffusion) and defocus:

Metal lamp with strong high-frequency interreflections:
Illustration of error correction and detection

Structured Light Patterns and MATLAB Code