Point cloud derivative products can be generated using what type of sensor?

• A. Passive only
• B. Active only
• C. Either passive or active
• D. None

Answer: (C)

Point cloud data come from 3D position information, which can be captured by either passive or active sensing. Passive sensors, like cameras, don’t emit energy—they simply collect light from the scene. When you have overlapping photos, photogrammetry or structure-from-motion techniques reconstruct 3D points to form a point cloud. Active sensors, such as LiDAR, emit a signal (like a laser) and measure the return time or phase to directly compute distances, producing a dense 3D point cloud. Since both approaches can yield the 3D point data used to create derivative products, point cloud derivatives can be generated from either passive or active sensing. The other options restrict to one type or to none, which doesn’t fit the reality of how point clouds are produced.