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.
1. A method of operating a portable electronic system in an augmented reality system, the method comprising:
with at least one processor:
obtaining a plurality of blocks comprising three-dimensional (3D) information about surfaces in a physical world, each block comprising a volumetric representation of a portion of the physical world at a point in time;
storing at least one of the plurality of blocks in an active memory;
using blocks from the active memory for rendering virtual content to a user of the portable electronic system;
persisting the blocks in the active memory upon transition to an inactive operation status at a first time;
upon a transition to an active operation status at a second time, after the first time, determining whether to use the persisted blocks for rendering virtual content to a user of the portable electronic system; and
paging blocks between the active memory and a local memory based on current or projected field of view of a user of the portable electronic system.
2. The method of claim 1 , wherein the blocks are mesh blocks.
3. The method of claim 1 , comprising: paging blocks between the active memory and a local memory based on current or projected field of view of a user of the portable electronic system wherein the plurality of blocks correspond to spaces of a same volume.
4. The method of claim 1 , further comprising, upon a transition to an inactive operation status, persisting the blocks in the local memory.
5. The method of claim 1 , wherein using blocks from the active memory for rendering virtual content to the user comprises using the blocks for visual occlusion processing, and computing physics-based interactions and/or environmental reasoning.
6. A non-transitory computer-readable medium with instructions stored thereon, that when executed on a processor, perform the acts comprising:
obtaining a plurality of blocks comprising three-dimensional (3D) information about surfaces in a physical world, each block comprising a volumetric representation of a portion of the physical world at a point in time;
storing at least one of the plurality of blocks in an active memory;
using blocks from the active memory for rendering virtual content to a user of the portable electronic system;
persisting the blocks in the active memory upon transition to an inactive operation status at a first time;
upon a transition to an active operation status at a second time, after the first time, determining whether to use the persisted blocks for rendering virtual content to a user of the portable electronic system; and
paging blocks between the active memory and a local memory based on current or projected field of view of a user of the portable electronic system.
7. The non-transitory computer-readable medium of claim 6 , wherein the blocks are mesh blocks.
8. The non-transitory computer-readable medium of claim 6 , wherein the acts comprise paging blocks between the active memory and a local memory based on current or projected field of view of a user of the portable electronic system the plurality of blocks correspond to spaces of a same volume.
9. The non-transitory computer-readable medium of claim 6 , wherein the acts comprise, upon a transition to an inactive operation status, persisting the blocks in the local memory.
10. The non-transitory computer-readable medium of claim 6 , wherein using blocks from the active memory for rendering virtual content to the user comprises using the blocks for visual occlusion processing, and computing physics-based interactions and/or environmental reasoning.