HMD Stereo Camera IR Illumination for Low Light Tracking
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Solution Overview
Problem
Conventional mixed-reality systems, including VR and AR, face challenges in accurately detecting depth and tracking movement, especially in low light environments due to insufficient anchor point detection and the need for additional hardware, which increases cost, weight, and battery consumption.
Innovation Solution
The implementation of a head-mounted device (HMD) equipped with a stereo camera system that captures visible and infrared light, using flood IR light illuminators to emit and detect reflected IR light, allowing for dynamic adjustment of illumination intensity to enhance movement tracking and depth detection in low light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional movement tracking systems are used in low light environments, then the system structure remains simple, but the detection accuracy deteriorates due to insufficient anchor point identification
Solution Approach 1:
The patent applies the principle of color changes by transitioning from visible light detection to infrared light detection. The system uses infrared illuminators to emit infrared light and infrared cameras to detect reflected infrared light, effectively changing the spectral domain from visible to infrared. This allows the system to operate in low visible light environments by utilizing a different part of the electromagnetic spectrum where illumination can be provided actively through infrared sources.
2Measurement precision
If additional hardware is added to improve movement detection in low light, then the detection capability improves, but the device weight and complexity increase
Solution Approach 1:
The patent merges the functions of illumination and detection into a unified infrared-based system. The infrared illuminators and infrared cameras are integrated to work together as a cohesive subsystem, where the illuminators provide active illumination and the cameras detect the reflected infrared light. This merging allows the system to achieve improved detection capability without proportionally increasing overall device complexity, as the infrared components are consolidated into a coordinated functional unit.
3Measurement precision
If additional hardware is added to improve movement detection, then the detection accuracy improves, but the battery consumption increases
Solution Approach 1:
The patent implements periodic action by controlling the infrared illuminators to operate in pulsed or intermittent modes rather than continuous operation. The system activates the infrared illuminators only when needed for infrared image capture, allowing periods of low or zero power consumption. This periodic operation significantly reduces overall battery consumption compared to continuous illumination, while still maintaining adequate detection accuracy during active tracking periods.
4Measurement precision
If flood IR light illuminators are used to emit infrared light, then the detection capability in low light environments improves, but the energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the infrared illuminator operation adaptive and controllable. The system dynamically adjusts the activation and intensity of infrared illuminators based on detected light conditions and tracking requirements. Rather than static continuous operation, the illuminators are activated only when low light conditions are detected or when tracking accuracy requires additional infrared illumination, optimizing the balance between detection capability and energy consumption.
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
This solution enables more accurate and efficient tracking of movements and depth determination in mixed-reality environments, even in low light conditions, while reducing the need for additional hardware and conserving power.
Implementation Method 1
The HMD includes one (or more) flood IR light illuminators that emit a flood of IR light. The orientation/positioning of the flood IR light illuminator enables the cameras to obtain images of the flood IR light that is reflected in the HMD environment.
Implementation Method 2
Reflected IR light is then detected by the HMDS cameras. And, the HMD's movements are determined/calculated using the reflected IR light.
Data Source
AI summary
A head-mounted device (HMD) is configured to perform head tracking, even in low light environments. The HMD includes a stereo camera pair that includes a first camera and a second camera having overlapping fields of view. Both cameras are mounted on the HMD and are configured to detect both visible light and infrared (IR) light. The HMD also includes a flood IR light illuminator that is configured to emit a flood of IR light that spans an illumination area that overlaps with the cameras' fields of view. The intensity of the IR light is sometimes modified to accommodate low light environmental conditions. The cameras obtain images of reflected IR light. These images are then used to track movements of the HMD, even in low light environments.