Dynamic Sensor Selection Balancing Eyewear Tracking Power and Accuracy

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Solution Overview

Problem

Wearable mobile devices face challenges in efficiently managing sensor power consumption and tracking accuracy while determining their position within a physical environment, as existing systems often switch off cameras during motion cessation, leading to inefficiencies.

Innovation Solution

The eyewear device adjusts sensor settings, such as turning on/off sensors, changing sampling rates, and adjusting resolution based on sensor status and environmental input to optimize tracking without degrading accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If cameras are switched off during motion cessation to reduce power consumption, then energy efficiency is improved, but tracking accuracy may deteriorate when motion resumes

Engineering Contradiction:
Improvepower consumptionVSAvoidtracking accuracy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts camera operation states based on real-time motion detection. The IMU continuously monitors motion, and when motion is detected, cameras are activated; when motion ceases, cameras are deactivated. This dynamic adaptation resolves the contradiction by making the system flexible rather than static, ensuring cameras are on only when needed for tracking while saving power during stationary periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the IMU to control camera operation. The IMU provides continuous motion status feedback, which triggers camera activation or deactivation decisions. This closed-loop feedback mechanism ensures that camera state changes are responsive to actual motion conditions, maintaining tracking accuracy during motion while reducing power consumption during stationary periods.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If all sensors operate continuously at high settings to maintain tracking accuracy, then measurement precision is improved, but power consumption increases

Engineering Contradiction:
Improvetracking accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of continuous high-power operation, the system uses periodic action by activating cameras only during motion periods and deactivating them during stationary periods. The IMU continuously monitors and triggers periodic camera activation only when motion is detected, reducing overall power consumption while maintaining tracking accuracy during active periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system changes operational parameters of sensors based on motion state. During motion, cameras operate at full resolution and frame rate for accurate tracking. During stationary periods, cameras are completely deactivated. This parameter change from full operation to complete shutdown resolves the contradiction between accuracy and power consumption.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cameras are activated frequently to ensure tracking accuracy during motion, then reliability is improved, but power consumption increases

Engineering Contradiction:
Improvetracking accuracyVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The IMU continuously monitors motion in advance, detecting motion cessation before it occurs. When the IMU detects that motion is stopping, it triggers camera deactivation proactively. This preliminary action ensures cameras are turned off just in time, preventing unnecessary power consumption while maintaining tracking accuracy during actual motion periods.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4172731B1Dynamic sensor selection for visual inertial odometry systems
Publication Date: 2025.10.15 SNAP INC
  • EP4172731B1 patent drawingFigure 1A
  • EP4172731B1 patent drawingFigure 1B
  • EP4172731B1 patent drawingFigure 1C

AI summary

Visual-inertial tracking of an eyewear device using sensors. The eyewear device monitors the sensors of a visual inertial odometry system (VIOS) that provide input for determining a position of the device within its environment. The eyewear device determines the status of the VIOS based information from the sensors and adjusts the plurality of sensors (e.g., by turning on/off sensors, changing the sampling rate, of a combination thereof) based on the determined status. The eyewear device then determines the position of the eyewear device within the environment using the adjusted plurality of sensors.