Eye Tracker Camera Bitrate Control by Eye Position Range
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Solution Overview
Problem
Existing head-mounted systems face challenges in achieving efficient eye tracking while maintaining a lightweight and non-overbearing form factor, as cameras for accurate tracking result in excessive power consumption and limited trackable eye positions.
Innovation Solution
A head-mounted system combines a camera and another device, such as a photosensor-oculography device, to track eye positions, adjusting image capture rates and power modes based on eye position ranges to optimize power usage and tracking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera is positioned in front of the eye to obtain clearer images and cover a wide range of eye positions, then measurement precision and adaptability are improved, but the device complexity and form factor are worsened
Solution Approach 1:
The patent introduces a light source as an intermediary element that projects light onto the eye, enabling the camera to capture clearer images of the eye's reflective surface. This mediator enhances measurement precision without requiring the camera to be positioned directly in front of the eye, thus maintaining a more acceptable form factor.
Solution Approach 2:
The patent positions the camera laterally (to the side) of the eye rather than in front of it, changing the spatial dimension of camera placement. This dimensional change allows the system to achieve wide eye position tracking coverage while maintaining a compact form factor suitable for head-mounted displays.
2Measurement precision
If cameras are used extensively for eye tracking to achieve accurate results, then measurement precision is improved, but power consumption is worsened
Solution Approach 1:
The patent implements periodic action by having the camera capture images at specific intervals rather than continuously. The light source is activated only when needed for image capture, and the system alternates between active measurement phases and low-power states, significantly reducing overall power consumption while maintaining tracking accuracy.
Solution Approach 2:
The patent employs dynamic operation by adjusting the camera's active state based on detected eye movements. When eye movement is detected, the camera activates to capture updated images; when the eye is stationary, the camera enters a low-power state. This dynamic approach maintains measurement precision while minimizing power consumption.
3Measurement precision
If the camera operates continuously at high bitrate to maintain tracking accuracy, then measurement precision is improved, but power consumption is worsened
Solution Approach 1:
The patent applies partial action by capturing images at reduced bitrates or lower frequencies when full measurement precision is not required. The system adjusts the level of measurement activity based on current tracking needs, using high-bitrate capture only when necessary and accepting reduced precision during stable periods, thereby reducing overall power 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 approach allows for accurate eye tracking with reduced power consumption, extending the range of trackable eye positions and maintaining a desirable form factor for widespread user adoption.
Implementation Method 1
Some examples of types of devices that may be used in eye tracking systems include photosensor-oculography devices
Data Source
AI summary
Systems, methods, and computer programs for efficient use of head-mounted cameras in eye tracking. In one embodiment, a system includes a head-mounted device that takes measurements indicative of positions of an eye of a user, and a head-mounted camera that captures images of the eye. A first range of eye positions trackable from the images is narrower than a second range of eye positions trackable from the measurements. A computer calculates the eye positions based on the measurements. When the eye positions fall within the first range, the computer reads images at a first bitrate from the head-mounted camera. And when the eye positions fall outside the first range, the computer refrains from reading images from the head-mounted camera, or reads the images from the head-mounted camera at a second bitrate that is less than half the first bitrate.