Portable Device Orientation Correction Using Idle Phase Gravitation
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Solution Overview
Problem
Portable devices used for displaying virtual or augmented reality struggle with accurate orientation estimation due to error-prone rotation rate sensors and the inability of acceleration sensors to distinguish between gravitational and movement-related accelerations, leading to energy-intensive and disruptive corrections.
Innovation Solution
A method that differentiates between idle and movement phases to correct orientation estimation using acceleration sensor data, measuring gravitational acceleration during idle phases for error calculation and applying correction values during movement phases in small steps to minimize user perception of changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous corrections of orientation estimation are performed using acceleration sensor data, then orientation accuracy is improved, but energy consumption increases and user comfort deteriorates
Solution Approach 1:
The system performs orientation correction periodically by detecting idle phases (when head movement is negligible) and applying corrections only during these phases. This periodic approach allows the system to maintain orientation accuracy while significantly reducing energy consumption compared to continuous correction, as the acceleration sensor and processing are activated only when needed to measure gravitational acceleration and calculate correction values.
Solution Approach 2:
The system performs preliminary measurement of gravitational acceleration during idle phases before corrections are needed during movement phases. By pre-calculating correction values based on acceleration sensor data collected when the device is stationary, the system prepares correction information in advance, reducing the computational load during active usage and lowering overall energy consumption.
2Measurement precision
If frequent corrections of the display are performed, then orientation accuracy is improved, but user comfort deteriorates due to disruptive corrections
Solution Approach 1:
The system applies display corrections periodically during idle phases when the user is stationary, rather than continuously during movement. This timing strategy ensures that corrections are applied when the user is least likely to notice them, reducing the disruptive effect on user comfort while still maintaining orientation accuracy through accumulated correction values.
Solution Approach 2:
The system accumulates correction values during idle phases before applying them during movement phases. By building up correction information in advance during periods when the user is stationary and less sensitive to display changes, the system minimizes the impact of corrections on user comfort during active usage, effectively cushioning against disruptive corrections.
3Measurement precision
If the acceleration sensor is used to correct orientation estimation, then orientation accuracy is improved, but the ability to distinguish between gravitational and movement acceleration is compromised
Solution Approach 1:
The system exclusively uses acceleration sensor data during idle phases when the device is stationary and not experiencing movement-induced acceleration. By limiting gravitational acceleration measurement to these specific idle periods, the system reliably distinguishes between gravitational and movement acceleration, ensuring accurate correction values without contamination from movement artifacts.
Solution Approach 2:
The system performs preliminary measurement of gravitational acceleration during idle phases before movement occurs. By collecting acceleration data when the device is known to be stationary, the system establishes a clean baseline of gravitational acceleration without interference from movement-induced accelerations, ensuring reliable distinction between the two types of acceleration for accurate orientation correction.
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 approach enhances the accuracy and efficiency of orientation correction, reducing energy consumption and preventing user discomfort from continuous corrections, while maintaining accurate display adaptation during head movements.
Implementation Method 1
measuring gravitational acceleration during idle phases for error calculation
Data Source
AI summary
A method for displaying pieces of visual information as a function of a spatial orientation of a portable device equipped with a first sensor for detecting orientation information and with an acceleration sensor, includes: estimating the spatial orientation based on the orientation information; ascertaining, based on sensor measurement data of the acceleration sensor, whether the device is in an idle phase or a movement phase; ascertaining an error of the estimation based on the orientation estimation ascertained in the idle phase and on the sensor measurement data of the acceleration sensor detected in the idle phase; using the orientation estimation unchanged in the idle phase for the display; successively correcting the error for the orientation estimation in a subsequent movement phase; and using the corrected estimation for the display in the movement phase.