Dynamic Light Barrier for High Resolution Gaze Tracking
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Solution Overview
Problem
High-resolution image sensors used in gaze tracking are expensive due to their large size and high pixel density, making them costly for efficient implementation of tracking algorithms.
Innovation Solution
An optical system that uses a dynamically configurable light barrier, such as an LCD barrier, to select specific pinholes and micro-prisms to direct light to the image sensor, allowing for higher resolution images to be obtained without increasing the sensor size or decreasing the depth of field, by selectively blocking or allowing light to pass through an array of masking elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large image sensor with high pixel density is used to achieve high resolution, then image resolution is improved, but device cost and size increase
Solution Approach 1:
The invention divides the imaging process into multiple sequential acquisitions, each capturing a different spatial region through controlled occlusion. Instead of using a single large high-resolution sensor, the system segments the field of view and acquires multiple low-resolution images that are later synthesized into a high-resolution composite image, thereby avoiding the need for expensive large-format sensors.
Solution Approach 2:
The patent introduces an occlusion element as an intermediary component that selectively blocks light paths to guide different regions of the scene through a smaller aperture. This intermediary device enables a small sensor to capture information that would otherwise require a large sensor, effectively mediating between the limited sensor size and the desired high resolution.
2Measurement precision
If multiple images are acquired sequentially to increase resolution, then image resolution is improved, but acquisition time increases
Solution Approach 1:
The system employs periodic occlusion patterns where the occlusion element rapidly switches between different blocking configurations in a predetermined sequence. This periodic action allows multiple regional images to be captured in quick succession, minimizing the total acquisition time while still gathering sufficient data for high-resolution reconstruction.
Solution Approach 2:
The occlusion patterns and acquisition sequence are pre-planned and predetermined before the actual imaging process begins. By preparing the occlusion sequence in advance, the system eliminates unnecessary delays during image capture, allowing rapid execution of the multi-acquisition process and reducing overall acquisition time.
3Reliability
If a small aperture is used to increase depth of field, then depth of field is improved, but light transmission decreases
Solution Approach 1:
Instead of relying on a small aperture to provide depth of field for the entire field of view, the system segments the scene into multiple regions and captures each region separately through a larger aperture. This segmentation allows each individual image to be captured with sufficient light transmission, while the composite result maintains extended depth of field through computational synthesis.
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 reduces the image sensor width from 10.2 mm to 2 mm while maintaining resolution and field of view, making high-resolution image acquisition more affordable and efficient for applications like gaze tracking.
Implementation Method 1
a collecting entrance lens (205) arranged to receive light from a scene and to illuminate a selected one of a plurality of pinholes
Implementation Method 2
a collecting entrance lens (205) arranged to receive light from a scene
Implementation Method 3
a micro-prism array (215) arranged to direct light passing through the pinholes to the image sensor (220)
Data Source
Figure 1a~1c
Figure 2~3
Figure 4a~4b
AI summary
The provided solution is an optical system comprising an image sensor (220, 620) and a collecting entrance lens (205, 605) having a predetermined field of view, the optical device further comprising a dynamically configurable light barrier (210, 610) having at least two masking elements (300), the dynamically configurable light barrier being configured so that only one of the masking elements can be set in a state in which light passes through, the at least two masking elements being configured so that images acquired by the image sensor when one of the at least two masking elements is configured in a state in which light passes through represent different portions of the predetermined field of view than images acquired by the image sensor when another one of the at least two masking elements is configured in a state in which light passes through.