Hand Posture Classification via Skeleton Segmentation

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Solution Overview

Problem

Controller-free interactive systems, such as gaming systems, struggle to detect and distinguish subtle hand gestures like open and closed hands due to limitations in motion estimation routines, which affect the accuracy and intuitiveness of user interaction.

Innovation Solution

The system receives a depth image from a capture device, estimates skeleton information, segments the hand region, extracts a shape descriptor, and classifies the hand state using training data to determine the posture of the hand, enabling more refined and intuitive interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If skeleton estimation is used to detect user motions, then major joints can be estimated, but subtle gestures cannot be detected

Engineering Contradiction:
Improvegesture detection precisionVSAvoidsubtle gesture detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the hand region from the depth image by identifying pixels within a bounding box defined by skeleton joint positions (wrist and finger tip). This segmentation isolates the hand region for detailed analysis, enabling detection of subtle gestures that would be invisible in full-body skeleton estimation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from 3D skeleton joint coordinates to 2D shape descriptor space by computing normalized pixel coordinates and distance metrics within the hand region. This dimensional transformation enables classification of hand states (open/closed) based on shape characteristics rather than relying solely on 3D joint positions.

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

2Adaptability or versatility

If traditional motion estimation is used, then system complexity remains low, but interactivity and user experience are limited

Engineering Contradiction:
Improveinteraction versatilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary actions by first estimating skeleton information to locate hand regions, then segmenting those regions before extracting shape descriptors and classifying hand states. This multi-stage preliminary processing enables refined gesture detection while maintaining system modularity and manageable complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8488888B2Classification of posture states
Publication Date: 2013.07.16 MICROSOFT TECHNOLOGY LICENSING LLC
  • US8488888B2 patent drawing
  • US8488888B2 patent drawing
  • US8488888B2 patent drawing

AI summary

Systems and methods for estimating a posture of a body part of a user are disclosed. In one disclosed embodiment, an image is received from a sensor, where the image includes at least a portion of an image of the user including the body part. The skeleton information of the user is estimated from the image, a region of the image corresponding to the body part is identified at least partially based on the skeleton information, and a shape descriptor is extracted for the region and the shape descriptor is classified based on training data to estimate the posture of the body part.