Steerable Infrared Illumination for Low-Light Hand Tracking
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Solution Overview
Problem
Operating image sensors in electronic devices under low ambient lighting conditions is challenging, as they often require supplemental illumination to capture clear images of user's hands or faces, while conserving power and avoiding disturbance to others.
Innovation Solution
Incorporating a steerable infrared illuminator with adjustable illumination systems that focus infrared light on the user's hands or faces, adjusting beam direction and intensity based on hand motion to ensure continuous illumination without wasting power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a wide-area illumination system is used to illuminate the user's hand in low light conditions, then the hand remains visible to the sensor, but power consumption increases and the illumination may disturb others
Solution Approach 1:
The illumination system uses an array of individually controllable light-emitting elements (LEDs) that can be selectively activated. Instead of illuminating a wide area, only the specific elements needed to illuminate the hand are activated, creating localized illumination exactly where the sensor needs to detect the hand while conserving power and avoiding disturbance to others.
Solution Approach 2:
The system dynamically adjusts the illumination pattern by selectively activating different elements in the array based on hand position feedback from the sensor. As the hand moves, the illumination follows it, maintaining optimal illumination coverage while minimizing the number of active elements to reduce power consumption.
2Use of energy by moving object
If a steerable illumination system is used to track the hand, then power is conserved by focusing illumination only where needed, but the system complexity increases
Solution Approach 1:
The illumination system is divided into an array of independent light-emitting elements, each capable of being controlled individually. This segmentation allows the system to activate only the specific elements needed to track and illuminate the hand, reducing overall power consumption while maintaining tracking capability through a relatively simple control architecture.
Solution Approach 2:
The system uses feedback from the sensor detecting hand position to automatically adjust which illumination elements are activated. This self-service mechanism allows the illumination to automatically follow the hand without requiring complex external control systems, reducing overall system complexity while achieving effective hand tracking.
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
The solution effectively tracks user hand motions in low light conditions, conserving power by focusing illumination only where needed, and maintaining image clarity without disturbing others.
Implementation Method 1
selectively activating light-emitting diodes in an array of diodes in an infrared light source
Implementation Method 2
using positioners to move the infrared light source and/or lens in the illuminator
Data Source
AI summary
A head-mounted device may include displays for presenting images to a user. The head-mounted device may have a hand tracker for gathering hand tracking input from a user. The hand tracker may include a steerable illumination system such as a steerable infrared illuminator. Infrared light may be steered by selectively activating light-emitting diodes in an array and/or using positioners to move an infrared light source and/or lens in the illuminator. An infrared image sensor may gather images of the hands. Based on the monitored movement of a hand, the steerable illumination system may steer the infrared light to ensure that the hand remains illuminated even during hand movements.