Light-Direction Detection Microchips for 6 DoF Motion Capture
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Solution Overview
Problem
Current motion-capture systems face challenges in accurately capturing six degrees of freedom (6 DoF) motion data, particularly when markers are close together or at similar angles, leading to data contamination and inability to track features like facial expressions, which limits realism in applications such as virtual reality and animation.
Innovation Solution
A camera-less optical motion-capture system utilizing light-direction detection (LDD) microchips with multiple photodiodes and predefined structures to measure light direction in multiple planes, combined with LED arrays flashing in specific patterns to provide 6 DoF data, and hybridized with camera-based systems for redundancy and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If camera-based systems with multiple lenses are used to detect IR signals, then motion capture capability is achieved, but system cost and complexity increase significantly
Solution Approach 1:
The patent extracts the light direction detection function from complex camera systems and implements it using simple photodiode arrays on a microchip. Each photodiode detects light intensity from a specific direction, and by comparing signals from multiple photodiodes, the system determines light direction without requiring lenses or complex optical paths.
Solution Approach 2:
The patent replaces mechanical camera systems with optical sensors (photodiodes) that directly detect light intensity. This substitution eliminates mechanical components like lenses and mirrors, reducing system complexity while maintaining motion capture functionality through electronic signal processing.
2Loss of information
If three or more passive markers are used to approximate 6 DoF, then rotational movement data can be obtained, but data accuracy decreases when markers are close together or at similar angles
Solution Approach 1:
The patent adds a new dimension of measurement by detecting light direction in addition to light intensity. Instead of relying solely on the positions of multiple markers, the system uses photodiodes arranged in specific geometric patterns that directly measure the angular direction of incoming light, providing independent 6 DoF data without requiring multiple markers in close proximity.
3Loss of information
If hybridized motion-capture systems pairing passive markers with inertial sensors are used, then 6 DoF data can be obtained, but system complexity and double integration errors increase
Solution Approach 1:
The patent merges light direction detection with motion capture in a single integrated system. The photodiode array simultaneously provides both position information (through light intensity variation) and orientation information (through light direction detection), eliminating the need for separate inertial sensors and avoiding double integration errors while reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement of 6 DoF motion data without the need for multiple cameras, reduces marker complexity, and enhances realism by providing detailed motion capture capabilities, including facial expressions, through improved light direction detection and data redundancy.
Implementation Method 1
pairs of photodiodes and any number of predefined structures formed on a substrate... measure light direction in multiple planes
Data Source
AI summary
Embodiments of an improved light-direction detection (LDD) device are described herein. The LDD device includes a substrate and at least one predefined structure formed along the substrate by stacking metal layers, contacts, and vias available in the manufacturing process of the device. The predefined structure is formed along a photodiode pair to collectively define an optical sensor configured to detect direction of incident light without need for off-chip components. The device accommodates light direction detection in two or more orthogonal planes.