HMD Marker Lighting Control for Tracking Accuracy
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Solution Overview
Problem
In head-mounted displays (HMDs) used for virtual reality, accurately tracking the position and posture of devices is challenging due to interference from non-marker lit portions in captured images, which can affect the accuracy of position and posture estimation.
Innovation Solution
The device includes a case body with a plurality of markers that emit light and a control portion to light these markers at predetermined intervals. The control portion also lights an indicator during periods when the markers are unlit, ensuring that only marker images are captured in the exposure period of image sensing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indicators are continuously lit to show device state, then user awareness of device status is improved, but accuracy of position and posture estimation deteriorates due to interference in captured images
Solution Approach 1:
The indicator is lit only during periods when markers are unlit, creating a periodic on/off pattern that prevents simultaneous illumination of both markers and indicator. This temporal separation ensures that captured images contain only marker light without indicator interference, while still providing periodic state information to the user.
Solution Approach 2:
The control portion determines whether to light the indicator based on whether markers are currently lit. By checking the marker lighting state before activating the indicator, the system prevents indicator illumination during marker capture periods, ensuring measurement accuracy is maintained while still providing device state indication when appropriate.
2Adaptability or versatility
If multiple light sources (markers and indicators) are lit simultaneously, then device functionality is enhanced, but image capture quality deteriorates due to included non-marker lit portions
Solution Approach 1:
The system uses periodic lighting where markers and indicator take turns being illuminated. During marker lighting periods, only markers emit light for accurate capture. During non-lighting periods of markers, the indicator can be lit to provide state information. This periodic alternation maintains both functionality and image quality.
Solution Approach 2:
The lighting function is segmented into two distinct temporal phases: marker lighting phase for accurate image capture and indicator lighting phase for state indication. By separating these functions in time rather than space, the system achieves both accurate imaging and comprehensive device functionality without mutual interference.
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 effectively prevents non-marker lit portions from being included in captured images, thereby enhancing the accuracy of position and posture estimation in virtual reality applications.
Implementation Method 1
a plurality of markers configured to emit light to the outside of the case body
Implementation Method 2
an image obtained by imaging the plurality of markers is analyzed, and the positions of marker images within the image are thus identified
Data Source
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AI summary
An input device 16 includes a case body, a plurality of markers 30 configured to emit light to the outside of the case body, and an indicator 32 configured to indicate the state of the input device 16. A control portion 50 lights the plurality of markers 30 at predetermined intervals, and lights the indicator 32 in a period during which the plurality of markers 30 are unlit.