Dynamic Light Source Power Optimization for Eye Tracking
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Solution Overview
Problem
Eye and gaze tracking systems face challenges in achieving precise gaze estimations while minimizing power consumption, particularly in mobile devices, due to the high intensity of infrared light sources used for illumination.
Innovation Solution
An imaging device optimizes light source power by balancing power consumption and image quality through precise calculation of illumination efficiency based on iris-pupil contrast and glint intensity, dynamically adjusting the power supplied to infrared light sources to reduce total power output while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-intensity infrared light sources are used to illuminate the subject's eye, then the precision and accuracy of gaze estimations are improved, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic power adjustment of infrared light sources based on real-time imaging conditions. The system continuously monitors image quality metrics (iris-pupil contrast, glint intensity) and adapts light source power levels accordingly, transitioning from static high-power operation to dynamic adaptive power control that maintains measurement precision while reducing overall power consumption.
Solution Approach 2:
The system changes operational parameters of the infrared light sources by adjusting power output levels based on calculated illumination efficiency. By modifying the power parameter dynamically according to imaging conditions and eye position, the system achieves optimal balance between gaze estimation accuracy and power consumption, avoiding sustained high-power operation.
2Illumination intensity
If multiple infrared light sources are used to improve illumination coverage, then image quality is improved, but total power consumption increases
Solution Approach 1:
The patent applies different power levels to different light sources based on their individual illumination efficiency and contribution to image quality. Rather than uniformly powering all light sources at maximum level, the system selectively adjusts each light source's power output according to local imaging requirements, optimizing the balance between illumination coverage and total power consumption.
Solution Approach 2:
The system uses partial action by activating and powering only the necessary subset of light sources required to achieve adequate illumination coverage. By calculating which light sources provide the most beneficial contribution to image quality metrics, the system avoids excessive power consumption from all light sources operating at full capacity simultaneously.
3Loss of energy
If light source power is reduced to minimize power consumption, then energy efficiency is improved, but image quality deteriorates
Solution Approach 1:
The system implements feedback control by continuously monitoring image quality parameters (iris-pupil contrast ratio, glint intensity) and using this information to adjust light source power levels. This closed-loop feedback mechanism ensures that power reduction does not compromise image quality below acceptable thresholds, maintaining energy efficiency while preserving sufficient imaging quality for accurate gaze tracking.
Solution Approach 2:
The system performs preliminary calculation of illumination efficiency and predicts optimal power levels before adjusting light source output. By pre-calculating the relationship between power consumption and image quality metrics, the system can proactively set appropriate power levels that prevent image quality deterioration while maximizing energy efficiency.
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
The solution effectively reduces power consumption while maintaining sufficient image quality for accurate eye and gaze tracking, enhancing the efficiency of imaging devices by optimizing light source power based on specific image parameters.
Implementation Method 1
an infrared (IR) camera includes high-intensity IR light sources that are used to illuminate a person's eye
Implementation Method 2
IR sensors that are used to detect the reflections (i.e., glints or Purkinje images) from the person's retina/cornea
Data Source
AI summary
Technologies for power optimization of light sources include an imaging device to generate a captured image of a subject. The imaging device analyzes the captured image to determine, in the captured image, a location of the subject's eye relative to the imaging device, an iris-pupil contrast of the subject's eye, and a glint intensity of glints present on the subject's eye. The imaging device determines, for each of a plurality of light sources, an illumination efficiency based on a distance between the camera and the subject's eye, a distance between the light source and the subject's eye, an incidence angle of the light source relative to the subject's eye, and a power profile of the light source. The imaging device determines an amount of power to supply to each light source to reduce a total cumulative power supplied to the light sources based on one or more power constraints.