AR Tracking Using Simplified 2D Façade Models

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Solution Overview

Problem

Augmented reality systems face challenges in maintaining accurate tracking between real and virtual objects, leading to jitter or unnatural placement of virtual items due to processor-intensive calculations required for complex 3D point cloud models, especially on resource-limited mobile devices.

Innovation Solution

The use of compressed or simplified 3D point cloud models and two-dimensional façade data, combined with initial rough location estimates from GPS or other location-based systems, to efficiently match and track virtual objects within an augmented reality environment, reducing processing demands and improving real-time performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex 3D point cloud models are used for tracking, then tracking accuracy is improved, but processing time and computational resources increase

Engineering Contradiction:
Improvetracking accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the complex 3D point cloud model into multiple simplified 2D façade components representing different building surfaces. Each façade is processed independently for feature detection and matching, reducing the computational burden of processing the entire 3D model as a single complex structure while maintaining tracking accuracy through cumulative façade matching.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates simplified 2D copies of 3D façade surfaces from the original complex 3D point cloud model. These 2D façade representations serve as computationally efficient substitutes that retain the essential geometric and visual characteristics needed for accurate tracking and matching, enabling real-time processing on mobile devices.

Inventive Principle:
Principle #26Copying

2Measurement precision

If complex 3D point cloud models are used for tracking, then tracking accuracy is improved, but device resource requirements increase

Engineering Contradiction:
Improvetracking accuracyVSAvoidprocessing power requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the complex 3D point cloud into multiple simpler 2D façade segments, each representing a portion of a building surface. This segmentation allows mobile devices with limited processing power to handle each façade independently, reducing the overall computational complexity while preserving the accuracy needed for precise virtual object placement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses lightweight 2D façade representations as simplified proxies for the heavy 3D point cloud data. These 2D models require significantly fewer computational resources to process and can be quickly generated and discarded, enabling resource-constrained mobile devices to perform accurate augmented reality tracking without needing powerful hardware.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Loss of time

If GPS location estimates are used, then processing time is reduced, but location precision decreases

Engineering Contradiction:
Improveprocessing timeVSAvoidlocation accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent uses GPS to obtain a preliminary rough location estimate before performing detailed image-based façade matching. This preliminary positioning narrows down the search area for subsequent processing, allowing the system to quickly identify relevant building façades in the vicinity and perform detailed matching only on those candidates, thereby reducing overall processing time while maintaining accuracy through the two-stage approach.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12079931B2Image and point cloud based tracking and in augmented reality systems
Publication Date: 2024.09.03 SNAP INC
  • US12079931B2 patent drawing
  • US12079931B2 patent drawing
  • US12079931B2 patent drawing

AI summary

Systems and methods for image based location estimation are described. In one example embodiment, a first positioning system is used to generate a first position estimate. Point cloud data describing an environment is then accessed. A two-dimensional surface of an image of an environment is captured, and a portion of the image is matched to a portion of key points in the point cloud data. An augmented reality object is then aligned within one or more images of the environment based on the match of the point cloud with the image. In some embodiments, building façade data may additionally be used to determine a device location and place the augmented reality object within an image.