Camera Latency Measurement via Controlled Light Source
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Solution Overview
Problem
Existing methods for measuring transmission time between a camera sensor and a screen are not accurate and reliable, as they fail to account for latency and are influenced by increasing light intensity and ambient light, which affects the measurement results.
Innovation Solution
The method involves using a light source, such as an LED, or an object with distinct properties to generate an image signal, ensuring the light source or object is switched on for a duration longer than the inverse frame rate of the camera, and using phototransistors to measure the signal transmission time, while shielding the camera from ambient light to isolate the light source's influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light source is used to generate an image signal for latency measurement, then the measurement can be performed, but increasing light intensity during switching on influences the measurement result
Solution Approach 1:
The patent changes the temporal parameters of the light source by switching it on for a duration longer than the inverse frame rate of the camera. This ensures the light is continuously present throughout the entire scanning process, eliminating measurement errors caused by increasing light intensity during the switching-on phase.
2Ease of manufacture
If ambient light is present during measurement, then the measurement setup is simpler, but ambient light influences the measurement results
Solution Approach 1:
The patent extracts the harmful ambient light from the measurement system by introducing a light shield between the camera and the environment. This isolation measures only the light from the controlled light source, eliminating ambient light interference while maintaining measurement simplicity.
Solution Approach 2:
The light shield acts as an intermediary element that selectively blocks ambient light while allowing the measurement light to pass through. This mediator creates a controlled optical environment without complicating the overall measurement setup.
3Use of energy by moving object
If the light source is switched on for a short duration, then energy consumption is reduced, but the light signal cannot be detected due to camera scanning characteristics
Solution Approach 1:
The patent applies partial action by switching the light source on for a duration that exceeds the minimum required (inverse frame rate). This excessive duration ensures the light is present throughout the entire scanning process, guaranteeing reliable detection while minimizing energy consumption.
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 allows for precise and reliable measurement of transmission time by eliminating the influence of increasing light intensity and ambient light, providing accurate latency measurements that are independent of camera scanning positions.
Implementation Method 1
a light sensor, in particular a phototransistor... the light sensor being positioned in front of the screen... the light source can be positioned directly in front of the light sensor
Data Source
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Figure 5~6
AI summary
Method for measuring a transmission time between the generation of an image signal in front of a camera sensor of a camera (2) and the display of the image signal on a screen (6), wherein an image signal is transmitted between the camera (2) and the screen (6), wherein a light source (1) is arranged in front of the camera sensor to generate an image signal and the light source (1) is switched on at a switching time for a switching duration and/or an object is arranged in front of the camera sensor to generate an image signal at an arrangement time for a positioning duration, wherein the switching duration or the positioning duration is greater than or equal to the frame rate of the camera, and a display time at which the image signal is displayed on the screen (6) is detected by means of a light sensor.