Eye Tracking System with Positioning Camera for Flexible Gaze Point Calculation
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Solution Overview
Problem
Conventional eye tracking systems are limited to tracking users at distances up to 100 cm, restricting their use in scenarios where the display or observed object is farther away, such as in surgical environments with limited space, where flexible positioning of the eye tracker relative to the monitor is necessary.
Innovation Solution
A system comprising a camera and computer configuration that allows for versatile positioning of the eye tracker relative to the monitor, using multiple cameras and computers to track the user's gaze and monitor position, enabling gaze point calculation over flexible geometry relations, and incorporating calibration methods with targets for extended range tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the eye tracker is mounted at a fixed location on the display to track users at typical distances, then the eye tracking system can provide stable gaze point tracking within the head box, but the system cannot track users when the display is positioned at distances larger than 100 cm
Solution Approach 1:
The system divides the tracking function into two independent components: an eye tracker that captures eye images and a separate positioning camera that tracks the display position. This segmentation allows each component to be optimized independently, enabling the eye tracker to maintain stable tracking while the positioning camera compensates for distance variations through coordinate transformation.
Solution Approach 2:
The positioning camera acts as an intermediary between the eye tracker and the display. It captures the display position and provides transformation data that allows the system to calculate gaze points on the display surface even when the display is moved beyond the traditional 100 cm range, thus mediating the relationship between fixed eye tracker and variable display position.
2Ease of operation
If the display is positioned at a distance larger than 100 cm from the user, then the surgical environment space constraints are satisfied, but conventional eye trackers cannot track the user anymore
Solution Approach 1:
The system introduces dynamic positioning capabilities through the positioning camera that continuously tracks the display position. This dynamic tracking allows the display to be freely positioned at various distances while the system automatically adjusts the coordinate transformation to maintain reliable eye tracking, making the previously static 100 cm limitation dynamic and adaptable.
Solution Approach 2:
The system changes the operational parameters by introducing a positioning camera that measures display position and uses coordinate transformation algorithms. This parameter change enables the system to operate beyond the traditional distance limits by mathematically adjusting the relationship between eye tracker coordinates and display coordinates based on the measured display position.
3Adaptability or versatility
If multiple cameras and computers are used to enable flexible positioning and extended range tracking, then the tracking distance and positioning flexibility are improved, but the system complexity increases
Solution Approach 1:
The positioning camera serves multiple functions: it tracks the display position, provides coordinate transformation data, and enables the system to adapt to various display configurations. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing system complexity while achieving versatile positioning capabilities.
Solution Approach 2:
The system replaces complex mechanical coupling between the eye tracker and display with an optical measurement system (positioning camera) and computational coordinate transformation. Instead of mechanically linking the components, the system uses visual tracking and mathematical transformation to achieve the same result, reducing mechanical complexity while maintaining positioning flexibility.
Data Source
AI summary
A system evaluates a point of gaze of a user on an object and includes at least one eye tracker camera and at least one positioning camera. The eye tracker camera and the positioning camera are configured to be arranged in fixed positions relative to each other. At least one light source is configured to provide conical reflection from at least one of a user's eyes. At least one computer and at least one object is provided. The geometrical data of the object is stored in a storage device accessible to the computer. Wherein the computer is configured to determine: a gaze line of said user relative to a 3D coordinate system, the position of said at least one object relative to said 3D coordinate system, and a gaze point calculated as the intersection of said gaze line with the surface of said object in said 3D coordinate system.