Single-Source Infrared Line-of-Sight Detection With 2D Purkinje Imaging
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Solution Overview
Problem
Existing line-of-sight detection technologies face challenges in achieving both a smaller form factor and higher accuracy due to the need for multiple light sources and limited freedom in their arrangement, which affects detection precision, particularly in the presence of individual eye differences.
Innovation Solution
A line-of-sight detection apparatus utilizing a single light source combined with an irradiation light dividing element to form multiple point-shaped optical images on the eyeball, and a micro light source array for two-dimensional image formation, enabling accurate line-of-sight information calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light sources are arranged on eyeglasses to form multiple Purkinje images, then line-of-sight detection accuracy is improved, but the apparatus size increases and the degree of freedom in light source arrangement is reduced
Solution Approach 1:
The patent divides the light from a single infrared light source into multiple beams using a beam dividing element (such as a microlens array or diffraction grating), creating multiple Purkinje images on the eyeball. This segmentation approach replaces the need for multiple separate light sources, reducing apparatus size while maintaining the capability to form multiple reference points for accurate line-of-sight detection
Solution Approach 2:
The patent introduces a beam dividing element as an intermediary component between the single light source and the eyeball. This intermediary element splits the light into multiple beams, enabling the formation of multiple Purkinje images without requiring multiple light sources, thus resolving the contradiction between detection accuracy and device complexity
2Device complexity
If a single light source with beam dividing element is used to form multiple point-shaped optical images, then apparatus size is reduced, but the ability to form two-dimensional array of Purkinje images is limited
Solution Approach 1:
The patent employs a two-dimensional array of microlenses or a diffraction grating with multiple orders as the beam dividing element. This configuration transforms the single light source's output into multiple beams arranged in a two-dimensional pattern, enabling the formation of Purkinje images distributed across two dimensions on the eyeball surface, thus achieving both compact size and two-dimensional detection capability
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 apparatus achieves high-accuracy line-of-sight detection with reduced size, minimizing the impact of eye variations and improving detection precision by forming Purkinje images in a two-dimensional array, thus enhancing operational efficiency.
Implementation Method 1
a dividing element configured to divide the light emitted from the single light source into a plurality of beams of the emitted light to form the plurality of point-shaped optical images
Implementation Method 2
The corneal reflection method is a method of calculating line-of-sight information from a near infrared eyeball image, and is based on the arrangement of a Purkinje image in the eyeball image
Data Source
AI summary
A line-of-sight detection apparatus includes an acquisition unit configured to acquire an eyeball image, an irradiation unit configured to irradiate an eyeball with light in an infrared wavelength band, forming a plurality of point-shaped optical images on the eyeball image, and a calculation unit configured to calculate line-of-sight information based on the eyeball image and the plurality of point-shaped optical images, wherein the irradiation unit includes at least one single light source configured to emit the light in the infrared wavelength band, and a dividing element configured to divide the light emitted from the single light source into a plurality of beams of the emitted light to form the plurality of point-shaped optical images.