AR Hand-Tracking Stabilization for Pinch-Target Accuracy

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Solution Overview

Problem

Existing hand interaction frameworks in augmented reality (AR) systems face challenges with hand pose estimation during pinch gestures, leading to instability in selecting target virtual 3D objects due to changes in hand pose.

Innovation Solution

Implementing an ML hand-tracking model trained on specially annotated hand-video frame tracking data to maintain hand pose invariance during pinch gestures, combined with temporal smoothing and filtering of skeletal 3D model features, and using composite hand features to minimize targeting changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hand pose estimation is used during pinch gestures, then hand interaction capability is improved, but target selection stability deteriorates due to hand pose changes

Engineering Contradiction:
Improvehand interaction capabilityVSAvoidtarget selection stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The hand tracking system segments the hand model into multiple independent components (wrist, palm, fingers, fingertips) and processes their stabilization differently. The wrist and palm positions are stabilized with higher priority than finger positions, allowing finger movement for gesture expression while maintaining overall hand position stability for accurate target selection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts stabilization parameters based on gesture context. During detected pinch gestures, the stabilization strength is increased for target selection-related hand features while maintaining responsiveness for gesture recognition. This adaptive parameter adjustment resolves the contradiction between interaction versatility and selection stability.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If temporal smoothing is applied to skeletal 3D model features, then hand tracking stability is improved, but responsiveness to actual hand movements deteriorates

Engineering Contradiction:
Improvehand tracking stabilityVSAvoidresponsiveness to hand movements
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The temporal smoothing filter is made dynamic rather than static. The filter strength adapts in real-time based on hand velocity, acceleration, and gesture context. During rapid hand movements or gesture transitions, the filter strength is reduced to maintain responsiveness. During steady-state hand positions, the filter strength is increased to enhance stability and reduce jitter.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system continuously monitors hand movement characteristics and uses this feedback to adjust the temporal smoothing parameters. When the system detects that smoothing is causing excessive lag or missing gesture events, it automatically reduces the filter strength. This closed-loop feedback mechanism maintains the optimal balance between stability and responsiveness.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS20250308178A1Hand-tracking stabilization
Publication Date: 2025.10.02 SNAP INC
  • US20250308178A1 patent drawing
  • US20250308178A1 patent drawing
  • US20250308178A1 patent drawing

AI summary

An Augmented Reality (AR) system provides stabilization of hand-tracking input data. The AR system provides for display a user interface of an AR application. The AR system captures, using one or more cameras of the AR system, video frame tracking data of a gesture being made by a user while the user interacts with the AR user interface. The AR system generates skeletal 3D model data of a hand of the user based on the video frame tracking data that includes one or more skeletal 3D model features corresponding to recognized visual landmarks of portions of the hand of the user. The AR system generates targeting data based on the skeletal 3D model data where the targeting data identifies a virtual 3D object of the AR user interface. The AR system filters the targeting data using a targeting filter component and provides the filtered targeting data to the AR application.