Pulsed NIR Illumination Synchronization for Interference Reduction
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Solution Overview
Problem
Existing object detection and tracking systems using Near-infrared (NIR) illumination face interference from other NIR sources, leading to reduced sensitivity and effectiveness, particularly in conditions of poor visibility like nighttime, due to the high cost and placement limitations of Far-infrared systems and the disturbance caused by continuous or pulsed NIR illumination from other vehicles.
Innovation Solution
An illumination apparatus employing small-pulse-width, high-power infrared pulses at a medium pulse rate, synchronized with a camera's shutter to minimize interference, utilizing a Near-infrared spectrum between 800-900 nm, which is less disturbing to other vehicles and allows for better visibility and object detection in low light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If continuous or pulsed NIR illumination is used for object detection, then visibility in poor light conditions is improved, but interference from other NIR sources increases reducing system sensitivity
Solution Approach 1:
The illumination source emits light in periodic pulses rather than continuously. The camera is synchronized to capture images during the illumination pulses, while the shutter blocks light during off-pulse periods. This periodic operation allows the system to tolerate higher illumination intensities while reducing cumulative interference from other NIR sources through temporal separation.
Solution Approach 2:
The system performs preliminary synchronization between the illumination source and camera shutter. The shutter is pre-configured to open during illumination pulses and close during off-pulse periods, ensuring that the camera is ready to capture images at the optimal moments before the illumination occurs, thereby maximizing signal detection while minimizing interference.
2Measurement precision
If high-power infrared pulses are used to improve detection sensitivity, then object detection capability is enhanced, but interference from spurious signals increases
Solution Approach 1:
High-power infrared pulses are emitted periodically rather than continuously. The camera shutter is synchronized to capture images only during these brief pulse periods. This temporal separation allows the use of high peak power for improved detection sensitivity while the duty cycle remains low, reducing the accumulation of spurious signals from the environment and other sources.
Solution Approach 2:
The system converts the potential harm of high-power pulses generating spurious signals into a benefit by using ultra-brief pulse durations. The high peak power provides excellent detection sensitivity, while the extremely short pulse width and low duty cycle ensure that spurious signals from reflections and other sources do not have time to accumulate to interfering levels.
3Reliability
If pulsed illumination with synchronized shutter is used to reduce interference, then system robustness in poor light conditions is improved, but device complexity increases
Solution Approach 1:
The trigger outputs from the illumination source and the shutter control inputs are merged into a single synchronization mechanism. The illumination source's internal timing signal directly triggers the shutter operation, eliminating the need for separate synchronization circuits and reducing overall system complexity while maintaining robust performance in poor light conditions.
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 solution enhances object detection and tracking by reducing spurious signal interference, achieving better visibility and robustness in poor light conditions while minimizing interference from other NIR sources, thus maintaining system sensitivity and user confidence.
Implementation Method 1
The illumination source may be at least one of: an infrared source; an infrared LED; or a near infrared source.
Implementation Method 2
The capture sensor may be at least one of: an infrared sensor; a sensor which detects energy having a wavelength longer than 800 nm; or a sensor which detects energy having a wavelength between 800 - 900 nm.
Data Source
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AI summary
One example discloses an illumination apparatus, including: a first illumination source, having a pulsed illumination output structure; and a capture sensor, having an image capture structure synchronized with and responsive to reflection signals generated by the pulsed illumination output signal structure. Another example discloses an article of manufacture including at least one non-transitory, tangible machine readable storage medium containing executable machine instructions for illumination which include: transmitting a first pulsed illumination signal from a first illumination source; capturing an image; and synchronizing the transmitting and capturing with a synchronization trigger.