Simulated Control for 3D Human Poses in VR
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Solution Overview
Problem
Current methods for generating 3D human poses in virtual reality and augmented reality applications are computationally intensive and unsuitable for real-time applications due to their reliance on trajectory optimization, which requires complex physics models and results in high approximation errors.
Innovation Solution
A simulation-based approach that integrates image-based kinematic inference and physics-based dynamics modeling, using a learnable kinematic pose refinement unit and dynamics-based control generation unit learned through reinforcement learning to achieve accurate and physically-plausible pose estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trajectory optimization-based methods are used to generate 3D human poses, then physical plausibility is improved, but computational complexity and latency increase making real-time applications unsuitable
Solution Approach 1:
The system segments the pose generation process into two distinct components: a kinematic pose refinement network that handles real-time pose prediction from video frames, and a separate dynamics-based control generation unit that ensures physical plausibility. This segmentation allows each component to be optimized independently, with the kinematic part providing real-time performance and the dynamics part providing physical accuracy, thereby resolving the contradiction between computational complexity and physical plausibility.
Solution Approach 2:
The patent introduces an intermediary reinforcement learning agent that acts as a mediator between the kinematic pose refinement network and the final pose output. This agent learns to generate dynamics-based control signals that adjust the kinematic poses to satisfy physical constraints, thereby ensuring physical plausibility without requiring complex trajectory optimization, thus reducing computational complexity while maintaining reliability.
2Reliability
If trajectory optimization is used to optimize forces for kinematic motion, then physically-grounded motion is achieved, but processing time increases due to batch processing requirements
Solution Approach 1:
The system performs preliminary action by pre-training the reinforcement learning agent offline to learn the mapping from kinematic poses to dynamics-based control signals. During real-time operation, the pre-trained agent can rapidly generate physically-plausible poses without performing complex trajectory optimization, thereby achieving physically-grounded motion with minimal processing time and enabling real-time applications.
Solution Approach 2:
The patent substitutes the traditional mechanical trajectory optimization system with a data-driven reinforcement learning agent. Instead of solving complex optimization problems at runtime, the system uses the pre-trained neural network agent to directly predict dynamics-based control signals, replacing the computationally intensive mechanical optimization process with a faster neural network inference process while maintaining physical plausibility.
3Ease of manufacture
If simple and differentiable physics models are used for trajectory optimization, then optimization tractability is improved, but approximation errors increase compared to advanced physics simulators
Solution Approach 1:
The reinforcement learning agent serves as an intermediary that bridges the gap between simple differentiable physics models and advanced physics simulators. The agent learns to compensate for the approximation errors of simple physics models by generating dynamics-based control signals that are corrected during training using rewards based on advanced physics simulations, thereby achieving high precision without sacrificing optimization tractability.
Solution Approach 2:
The system changes the parameters of the physics model by using simple differentiable physics models for the core optimization process while incorporating learned correction parameters from the reinforcement learning agent. These learned parameters adjust the simple physics model outputs to match the accuracy of advanced physics simulators, thereby maintaining optimization tractability while reducing approximation errors.
Data Source
AI summary
A method for simulating a solid body animation of a subject includes retrieving a first frame that includes a body image of a subject. The method also includes selecting, from the first frame, multiple key points within the body image of the subject that define a hull of a body part and multiple joint points that define a joint between two body parts, identifying a geometry, a speed, and a mass of the body part to include in a dynamic model of the subject, based on the key points and the joint points, determining, based on the dynamic model of the subject, a pose of the subject in a second frame after the first frame in a video stream, and providing the video stream to an immersive reality application running on a client device.


