Gated Camera Ambient Light Subtraction for Daylight Detection
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Solution Overview
Problem
Existing methods for operating illumination devices and optical sensors in gated camera systems are inadequate for situations with daylight and strong sunlight, as they often rely on a single illumination source and are limited in range, with previous methods only effective up to 80 meters and not suitable for varying ambient lighting conditions.
Innovation Solution
A method involving the coordinated control of two illumination devices and an optical sensor to capture multiple images, with one image taken during illumination by each device and a third image in the absence of illumination, allowing for the formation of a difference image that accounts for ambient light, enabling robust and reliable object detection and distance measurement across a wider visible range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single illumination device is used in gated camera systems, then the device complexity is reduced, but the measurement precision and detection reliability deteriorate in daylight and strong sunlight conditions
Solution Approach 1:
The illumination function is segmented into multiple independent illumination devices (first illumination device and second illumination device) that operate in coordination. Each illumination device emits light pulses independently, allowing the system to capture multiple images with different illumination conditions, thereby improving measurement precision in daylight environments while maintaining manageable device complexity through modular architecture.
2Length of moving object
If the illumination duration is extended to improve visible range, then the detection range increases, but the temporal resolution and ability to distinguish distant objects deteriorates
Solution Approach 1:
The illumination devices emit light in periodic pulse sequences rather than continuous illumination. Each pulse is synchronized with the gated camera's exposure window, creating a periodic illumination pattern that extends the visible distance range through multiple pulses while maintaining temporal resolution by keeping each individual pulse duration short and precisely timed.
3Illumination intensity
If ambient light is included in captured images to improve image quality, then the image brightness increases, but the object detection reliability deteriorates in high ambient light conditions
Solution Approach 1:
The system extracts and separates the ambient light component from the total captured signal. By capturing images with and without illumination device activation, the system can isolate the ambient light contribution and subtract it from the illuminated images, thereby removing the harmful ambient light interference while preserving the useful reflected light from objects, improving object detection reliability.
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 reliable object detection and distance measurement beyond previous limitations, with improved robustness and accuracy in daylight conditions by subtracting ambient light influence and utilizing image registration to compensate for vehicle motion, achieving accurate distance estimation with minimal error.
Implementation Method 1
the optical sensor captures a first image, during an illumination by means of the first illumination device
Implementation Method 2
the first illumination device, the second illumination device emit a predefined number of light pulses
Data Source
AI summary
A method for operating a first illumination device, a second illumination device, and an optical sensor includes controlling the first illumination device, the second illumination device, and the optical sensor in a temporally coordinated manner and assigning a visible distance range to the coordinated control. During an illumination by the first illumination device, the optical sensor captures a first image by the coordinated control. During an illumination by the second illumination device, the optical sensor captures a second image by the coordinated control. During a time of an absence of an illumination by the first illumination device and the second illumination device, the optical sensor captures a third image. A difference captured image is formed from the first captured image, the second captured image, and the third captured image.