Dual-Camera LED Flicker Mitigation via Temporal Offset Triggering
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Solution Overview
Problem
Vehicle imaging systems often produce LED flicker artifacts when capturing images of light sources with LEDs, leading to incorrect interpretations by vehicle controllers, such as mistaking a red traffic light as off, which can be annoying and potentially hazardous.
Innovation Solution
The implementation of a dual-camera system with a temporal offset in their pulse trigger sequences to capture images of light sources, allowing the controller to compare images and accurately determine the status of LEDs, thereby mitigating flicker artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera captures images of LED light sources, then the imaging system is simple, but LED flicker artifacts appear in the captured images
Solution Approach 1:
The imaging system is segmented into multiple cameras (first camera and second camera) that operate independently but capture the same scene. Each camera has its own pulse trigger sequence with temporal offset, allowing independent control of their image capture timing relative to LED flicker cycles.
Solution Approach 2:
The solution introduces a temporal dimension by applying temporal offset between the pulse trigger sequences of multiple cameras. This temporal staggering ensures that different cameras capture LED light sources at different phases of the flicker cycle, enabling the system to overcome the limitations of single-camera timing.
2Object-affected harmful factors
If the pulse repetition frequency is increased to reduce visible flicker, then human eyes do not notice flickering, but imaging artifacts still occur due to camera capture timing
Solution Approach 1:
The system performs preliminary timing adjustment by applying temporal offset to the pulse trigger sequences before image capture occurs. This preliminary action ensures that images are captured at optimal moments relative to the LED flicker cycle, preventing artifacts before they can be recorded.
Solution Approach 2:
The controller receives images from multiple cameras and uses feedback to determine the actual state of LED light sources. By comparing images captured at different temporal phases, the system can identify and correct flicker-induced measurement errors, ensuring accurate detection of light source states.
3Reliability
If hardware solutions like LOFIC or image processing solutions are used, then LED flicker can be mitigated, but the device complexity and processing requirements increase
Solution Approach 1:
The solution merges the functionality of multiple cameras into a unified imaging system where the controller coordinates pulse trigger sequences and integrates images from multiple sources. This combining approach achieves flicker mitigation through coordinated multi-camera capture rather than complex single-camera hardware modifications.
Data Source
AI summary
This disclosure is generally directed to mitigating light-emitting diode (LED) imaging artifacts in an imaging system of a vehicle. In an example embodiment, the imaging system includes a first camera that operates under control of a first pulse trigger sequence, and a second camera that operates under control of a second pulse trigger sequence. The second pulse trigger sequence has a temporal offset with respect to the first pulse trigger sequence. The first camera captures an image of a light source, such as a traffic light containing LEDs. This image may contain an LED imaging artifact indicating that the traffic light is off. The second camera also captures an image of the light source. The temporal offset of the second pulse trigger sequence may eliminate the LED imaging artifact in the second image. A controller may compare the two images and determine that the traffic light is actually on.