Which data-capture modality provides dense 3D point clouds with accurate distances?

• A. LiDAR
• B. Photogrammetry
• C. Structured-light/laser scanning
• D. Thermal imaging

Answer: (A)

LiDAR works by sending out rapid laser pulses and measuring how long each pulse takes to bounce back. That time-of-flight directly translates to distance to the surface, and when many pulses are issued across a scene, they generate a dense set of 3D coordinates (a point cloud) that accurately represents real-world distances. The data combine high sampling density with precise range measurements, making LiDAR especially reliable for detailed, metric 3D surveys in outdoor or complex environments.

Photogrammetry, by contrast, derives 3D structure from overlapping photos and reconstructs distances through stereo matching and geometry; its accuracy and density depend on texture, lighting, and image coverage, and it can be less consistent for precise metric distances. Structured-light and laser-scanning systems can also produce dense 3D data, but they often have practical limitations in range and outdoor lighting and may not match LiDAR’s robust performance at longer distances. Thermal imaging, on the other hand, captures temperature information and does not produce accurate 3D geometry.