3D Joint Heatmap Alignment for Asynchronous Camera Motion Capture

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Solution Overview

Problem

Existing multi-camera object motion reconstruction systems face challenges in accurately synchronizing asynchronous cameras due to differences in image-capture resolution, frame capture rate, and shuttering speed, leading to inaccurate identification of key points and poor synchronization, which is time-consuming to calibrate individually.

Innovation Solution

A multi-camera system using asynchronous cameras generates three-dimensional joint heatmaps to determine a time delay between cameras, aligning temporal features, and computes a motion journal without individual camera calibration, utilizing a neural network to shift and align heatmaps based on intersection over union (IoU) values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If individual camera calibration is performed to synchronize multi-camera systems, then measurement precision of key point identification improves, but loss of time increases due to time-consuming calibration process

Engineering Contradiction:
Improvekey point identification accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically determining time delays between cameras through neural network processing of joint heatmaps, eliminating the need for manual individual camera calibration while maintaining synchronization accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes the calibration approach from individual camera parameter adjustment to global time delay adjustment based on heatmap correlation, transforming the calibration process into a more efficient parameter optimization problem

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If asynchronous cameras with different frame capture rates are used to reduce system cost, then device complexity decreases, but measurement precision of motion reconstruction deteriorates

Engineering Contradiction:
Improvecamera system configurationVSAvoidmotion reconstruction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the temporal alignment of frames from cameras with different frame rates by using neural network-based time delay determination, allowing flexible synchronization without requiring uniform camera specifications

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system introduces joint heatmaps as an intermediary representation that bridges asynchronous camera data, enabling accurate motion reconstruction by correlating temporal features across different frame rates

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If multiple cameras with different resolutions and shuttering speeds are used to increase adaptability, then adaptability improves, but manufacturing precision of synchronized motion data deteriorates

Engineering Contradiction:
Improvecamera configuration flexibilityVSAvoidsynchronized motion data accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system creates a universal synchronization method that works across cameras with varying specifications by using neural network-based temporal alignment, making the system adaptable to different camera configurations while maintaining data accuracy

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS12602797B2Reconstruction of body motion using a camera system camera system for reconstruction of body motion based on 3D joint heat map
Publication Date: 2026.04.14 RAPSODO
  • US12602797B2 patent drawing
  • US12602797B2 patent drawing
  • US12602797B2 patent drawing

AI summary

A method may include collecting first and second image data of an object motion, the first and second image data respectively including first and second frames captured by a first and a second camera. The method may include identifying an object included in the first and second frames and modeling two-dimensional pose estimations of the object for each identified frame. The two-dimensional pose estimations may indicate coordinate positions of the object features that contribute to the object motion. The method may include generating a first and a second three-dimensional joint heatmap corresponding to the object identified in the first and second frames based on features indicated in the two-dimensional pose estimations. The method may include determining a time delay between the first and second cameras based on the three-dimensional joint heatmaps and generating a motion journal that summarizes the motion associated with the object based on the time delay.