Purkinje LED Synchronization with Camera Frames
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Solution Overview
Problem
Existing eye movement tracking devices face challenges in synchronizing the Purkinje LED with camera frames without external synchronization inputs, leading to compatibility issues with various camera models and environmental artifacts affecting Purkinje point recognition.
Innovation Solution
The method synchronizes the Purkinje LED with camera frames using the internal clock of analog or digital shooting devices, extracting frame synchronization information from the video signal to control the LED's activation during odd or even frames, allowing for compatible operation across different camera types and environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external synchronization input is used to control LED timing, then synchronization precision is improved, but device complexity and camera compatibility worsen
Solution Approach 1:
The system uses the camera's own internal clock signal to control the LED timing, making the camera serve itself for synchronization purposes. This eliminates the need for external synchronization inputs and complex external control systems, while maintaining precise synchronization between LED activation and frame capture.
Solution Approach 2:
The synchronization method works with any camera that has an internal clock, making the system universally compatible across different camera models without requiring specific external synchronization connectors or inputs. This multi-functional approach allows the same system to work with various camera types.
2Measurement precision
If external synchronization input is used to control LED timing, then synchronization precision is improved, but adaptability to different camera models worsens
Solution Approach 1:
The synchronization method works with any camera that has an internal clock, making the system universally compatible across different camera models without requiring specific external synchronization connectors or inputs. This multi-functional approach allows the same system to work with various camera types.
Solution Approach 2:
Each camera uses its own internal clock for synchronization, allowing the system to adapt to any camera model independently without requiring external adaptation mechanisms or model-specific configurations.
3Difficulty of detecting and measuring
If image processing is used to identify Purkinje point, then detection capability is improved, but reliability in noisy environments worsens
Solution Approach 1:
The LED is activated periodically in synchronization with alternating frames (odd/even frames), creating a temporal pattern that distinguishes the Purkinje point signal from continuous ambient light. This periodic activation allows the system to reliably identify the Purkinje point even in noisy environments by looking for the characteristic periodic signal pattern.
Solution Approach 2:
By activating the LED only during specific synchronized frames, the system preemptively prevents ambient light artifacts from contaminating the Purkinje point measurement. The selective timing creates a controlled illumination pattern that counteracts the harmful effect of continuous ambient light.
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 enables effective synchronization of the Purkinje LED with camera frames, improving compatibility with diverse camera models and reducing environmental artifacts, thereby enhancing the accuracy of Purkinje point detection and gaze direction tracking without the need for complex calibration.
Implementation Method 1
placing an LED (light-emitting diode) emitting radiation in the infrared wavelengths right next to the lens of the camera
Implementation Method 2
This light is reflected on the cornea of the eye: a luminous point then appears on the image of the cornea of the eye captured by the camera
Implementation Method 3
a camera placed about ten centimeters from the subject's head in the axis of the subject's gaze. This camera directly filming the area of the eye
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
The invention relates to a device and to a method for synchronising a light wave with an electronic signal comprising images that are made of interleaved frames, characterised in that said method comprises the following steps: the reception (20) of the electronic signal by a box; the extraction (13) of first information by the identification of even and odd frames restored by the signal; the processing (14) said first information from the detection of even and odd images restored by the electronic signal; the calculation (15) from a logical operation carried out on the basis of the odd frames and odd images thus obtained; and the transmission (21) of a command to a light source supply module based on the results of said calculation.