Foreground Object Detection in Augmented Reality

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Solution Overview

Problem

Current augmented reality (AR) interaction methods are limited and non-intuitive, as users rely on physical input elements or virtual buttons, which do not allow natural interaction with virtual objects, especially under partial occlusions.

Innovation Solution

A method and apparatus that detect and track a movable foreground object, such as a user's fingers, in captured images without depth information, by warping and comparing images to segment and render augmentations, enabling natural interaction with AR objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If virtual buttons are used for interaction, then user interaction with AR objects is enabled, but the interaction feels non-intuitive and unnatural

Engineering Contradiction:
Improveintuitiveness of interactionVSAvoidinteraction mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces physical buttons and traditional virtual button interfaces with direct hand gesture recognition. The system uses computer vision to detect and track hand movements, allowing users to interact with AR objects through natural hand motions rather than mechanical or virtual button interfaces. This substitution of mechanical interaction systems with vision-based gesture recognition enables intuitive and natural user interaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If pattern-based AR systems are used, then accurate registration of virtual objects is achieved, but robustness to partial occlusions is insufficient

Engineering Contradiction:
Improveregistration accuracyVSAvoidrobustness to occlusion
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the scene into foreground (hand) and background (AR pattern) components using image processing techniques. By separating the hand detection from the pattern recognition processes, the system can accurately track hand gestures even when the hand partially occludes the AR pattern. This segmentation allows independent optimization of both pattern registration accuracy and hand tracking robustness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary background subtraction process that compares current frames with reference frames to identify foreground hand movements. This intermediary step acts as a mediator between the raw image data and the final gesture recognition, enabling the system to distinguish hand occlusions from pattern features and maintain reliable tracking under partial occlusion conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If hand tracking is implemented, then natural interaction with virtual objects is achieved, but detection accuracy under occlusion is reduced

Engineering Contradiction:
Improvenatural interaction capabilityVSAvoidhand detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent performs preliminary background modeling by capturing reference frames before hand interaction begins. This preliminary action creates a baseline representation of the scene without hands, which is then used to subtract background elements from subsequent frames. By preparing this reference background in advance, the system maintains high hand detection accuracy even when hands occlude significant portions of the scene, as the background subtraction isolates hand features from occluded pattern areas.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2941756B1Rendering augmented reality based on foreground object
Publication Date: 2021.03.17 QUALCOMM INC
  • EP2941756B1 patent drawingFigure 1
  • EP2941756B1 patent drawingFigure 2~3A
  • EP2941756B1 patent drawingFigure 3B~4

AI summary

A mobile device detects a moveable foreground object in captured images, e.g., a series of video frames without depth information. The object may be one or more of the user's fingers. The object may be detected by warping one of a captured image of a scene that includes the object and a reference image of the scene without the object so they have the same view and comparing the captured image and the reference image after warping. A mask may be used to segment the object from the captured image. Pixels are detected in the extracted image of the object and the pixels are used to detect the point of interest on the foreground object. The object may then be tracked in subsequent images. Augmentations may be rendered and interacted with or temporal gestures may be detected and desired actions performed accordingly.