US Patent 11302081 Caching and updating of dense 3D reconstruction data

A method to efficiently update and manage outputs of real time or offline 3D reconstruction and scanning in a mobile device having limited resource and connection to the Internet is provided. The method makes available to a wide variety of mobile XR applications fresh, accurate and comprehensive 3D reconstruction data, in either single user applications or multi-user applications sharing and updating the same 3D reconstruction data. The method includes a block-based 3D data representation that allows local update and maintains neighbor consistency at the same time, and a multi-layer caching mechanism that retrieves, prefetches, and stores 3D data efficiently for XR applications. Between sessions of an XR device, blocks may be persisted on the device or in remote storage in one or more cache layers. The device may, upon starting a new session, selectively use the blocks from one or more layers of the cache.