occlusionhandling

Occlusion handling refers to methods for dealing with occlusion, where a scene element is partially or fully hidden by another object, across domains such as computer graphics, computer vision, and augmented reality. The goal is to determine visibility, preserve realism, or maintain tracking and interaction despite hidden components.

In computer graphics, occlusion handling aims to avoid rendering objects that are not visible to the camera. This is achieved through techniques such as occlusion culling, depth testing (the Z-buffer), and occlusion queries. Data structures such as biological scene graphs like BSP trees, bounding volume hierarchies, as well as quadtrees and octrees, organize the scene to test visibility efficiently. Precomputed visibility databases (PVS) and portal rendering reduce work for static scenes. Occlusion mapping and hierarchical Z-buffer methods approximate visibility for dynamic scenes and can be combined with conventional rasterization to improve performance and maintain frame rates.

In computer vision and augmented reality, occlusion handling focuses on recognizing or tracking objects when parts are hidden, and on rendering virtual content that correctly appears behind real geometry. Approaches include robust feature matching under partial visibility, temporal integration, and multiple-hypothesis tracking. 3D scene reasoning using depth sensors or stereo geometry helps predict hidden surfaces. AR systems often leverage depth maps and real-time geometry to perform proper depth ordering and compositing so virtual objects are occluded by real objects as in the physical world.

Challenges include dynamic or non-rigid occluders, depth uncertainty, latency, and the trade-off between accuracy and performance. Evaluation typically considers visibility estimation accuracy, rendering efficiency, and robustness of tracking under occlusion. Occlusion handling is essential in interactive graphics, robotics, and mixed-reality applications.