Articulated Body Pose Estimation Using 3D Depth Data

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Solution Overview

Problem

Current techniques face challenges in accurately detecting, tracking, and estimating the pose of articulated bodies, such as hands, due to viewpoint variability, complex articulations, and self-occlusions, especially when relying on 2D image data, and there is a need for improved methods using 3D data from consumer-grade sensors.

Innovation Solution

The implementation of an iterative closest point (ICP) technique combined with inverse kinematics (IK) for refining kinematic model parameters, allowing for accurate alignment of a kinematic model with 3D point clouds from consumer-grade sensors, using methods like particle swarm optimization, Levenberg Marquardt, and iterative closest point inverse kinematics (ICPIK) to handle non-rigid transformations and kinematic constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If 2D image data is used for detecting and tracking articulated bodies, then the device complexity is reduced, but the measurement precision and reliability deteriorate due to viewpoint variability, complex articulations, and self-occlusions

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from 2D image data to 3D depth data for articulated body detection and tracking. By using depth information from consumer-grade 3D sensors, the system overcomes the limitations of 2D data including viewpoint variability, complex articulations, and self-occlusions, thereby improving measurement precision while maintaining device complexity at an acceptable level through the use of affordable sensors and efficient algorithms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If conventional optimization techniques are used for matching articulated body models to 3D data, then the manufacturing precision is improved, but the productivity deteriorates due to high computational time

Engineering Contradiction:
Improvepose estimation accuracyVSAvoidcomputational speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing model-to-data matching in an optimized sequence and using pre-computed kinematic constraints to guide the optimization process. This approach reduces the search space for optimization algorithms, enabling faster convergence to accurate pose estimates without sacrificing precision, thereby improving computational speed while maintaining pose estimation accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If iterative optimization methods are applied to refine kinematic model parameters, then the measurement precision is improved, but the loss of time increases due to multiple iterations required for convergence

Engineering Contradiction:
Improvepose estimation accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements feedback mechanisms where the optimization process continuously evaluates the match between the articulated body model and 3D depth data, using the error signals to guide parameter refinement. This feedback-driven approach ensures that iterative optimization converges efficiently to accurate pose estimates, minimizing the number of iterations required while maintaining high measurement precision through intelligent use of depth information and kinematic constraints.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9911219B2Detection, tracking, and pose estimation of an articulated body
Publication Date: 2018.03.06 INTEL CORP
  • US9911219B2 patent drawing
  • US9911219B2 patent drawing
  • US9911219B2 patent drawing

AI summary

Techniques related to pose estimation for an articulated body are discussed. Such techniques may include extracting, segmenting, classifying, and labeling blobs, generating initial kinematic parameters that provide spatial relationships of elements of a kinematic model representing an articulated body, and refining the kinematic parameters to provide a pose estimation for the articulated body.