Multi-View Pose Tracking via Probabilistic Graphical Models

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Solution Overview

Problem

In dynamic environments with multiple digital cameras, accurately recognizing and tracking poses or gestures of individuals is challenging due to overlapping fields of view, varying sizes and shapes of objects, and complex motion patterns, especially when numerous people, objects, or machines are present.

Innovation Solution

The system captures synchronized digital images from multiple calibrated color cameras with overlapping fields of view, uses classifiers like artificial neural networks to detect body parts, and constructs a graphical model by associating compatible candidates, defining edges based on temporal, triangulation, and regression probabilities to track motion and recognize poses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple digital cameras are used to capture imaging data from different fields of view, then the coverage area increases, but the difficulty of recognizing and tracking poses among multiple actors increases

Engineering Contradiction:
Improvecoverage areaVSAvoiddifficulty of recognizing poses
Core Design Contradiction:
Area of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The system segments the recognition task by first identifying individual body parts (heads, torsos, limbs) separately in each camera's field of view, then grouping compatible body parts into complete actor models. This segmentation approach allows the system to handle multiple actors across multiple cameras by breaking down the complex pose recognition into manageable parts that can be independently detected and then assembled.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from two-dimensional image analysis to three-dimensional spatial reasoning by using triangulation across multiple camera views. By incorporating depth information and spatial relationships from multiple camera angles, the system can accurately track actor poses and distinguish between multiple actors even in crowded environments, effectively adding a dimensional aspect to the recognition process.

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

2Ease of operation

If digital cameras are fixed in orientation to simplify operation, then ease of operation improves, but the ability to track motion and recognize poses deteriorates

Engineering Contradiction:
Improveease of camera configurationVSAvoidability to track motion
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system employs dynamic pose estimation that adapts to varying camera orientations and actor motions. By using probabilistic graphical models that can handle arbitrary camera configurations and dynamic scene changes, the system maintains reliable pose tracking even with fixed cameras, as the computational model dynamically adjusts to the static camera setup rather than requiring physical camera movement.

Inventive Principle:
Principle #15Dynamics

3Extent of automation

If frame-to-frame analysis is used to detect actions, then automation improves, but false detections increase in complex scenes

Engineering Contradiction:
Improveautomation of action detectionVSAvoidaccuracy of detection
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The system incorporates feedback mechanisms where the pose estimation from previous frames informs the current frame analysis, and detection results are continuously refined based on compatibility checks across multiple views. The probabilistic graphical model uses temporal consistency feedback to distinguish true actions from false detections, allowing automated detection while maintaining high accuracy in complex scenes through iterative refinement.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11783613B1Recognizing and tracking poses using digital imagery captured from multiple fields of view
Publication Date: 2023.10.10 AMAZON TECH INC
  • US11783613B1 patent drawing
  • US11783613B1 patent drawing
  • US11783613B1 patent drawing

AI summary

Poses or gestures of actors within a scene may be detected and tracked using multiple imaging devices aligned with fields of view that overlap at least in part. Images captured by the imaging devices may be synchronized and provided to a classifier to recognize body parts within the images, and score maps indicative of locations of peak probabilities that the images include the respective body parts may be generated. Locations of peak values within the score maps may be correlated with one another to confirm that a given body part is depicted in two or more fields of view, and vectors indicative of distances to or ranges of motion of body parts, with respect to the given body part, may be generated. Motion of the body parts may be tracked in subsequent images, and a virtual model of the body parts may be generated and updated based on the motion.