Which 3D sensing modality typically requires projecting structured light patterns onto the scene for depth computation?

• A. Stereo vision.
• B. Time-of-flight.
• C. Structured light.
• D. Monocular shading.

Answer: (C)

This question is about how depth information is obtained using active light patterns. The method that typically requires projecting known light patterns onto a scene to compute depth is structured light. In this approach, a projector emits a coded pattern (like stripes or a grid) and a camera watches how that pattern wraps around and distorts on surfaces. By comparing the observed pattern to the known projection, the system can triangulate the 3D coordinates of points in the scene.

Stereo vision, by contrast, uses two cameras and recovers depth from parallax without projecting anything. Time-of-flight systems measure how long light takes to travel to the scene and back, using pulsed or modulated light rather than a structured pattern. Monocular shading relies on shading cues within a single image to infer depth, which is indirect and not a direct, pattern-based depth computation.