Night Fog Detection via Halo and Backscattering Analysis
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Solution Overview
Problem
Existing devices for detecting fog and other visibility-disturbing elements at night are either too expensive, require specific targets, or are not reliable across various atmospheric conditions, limiting their effectiveness.
Innovation Solution
A method that combines halo detection around light sources and analysis of backscattered light from stationary or swivel-mounted light sources to determine the presence of fog, smoke, rain, or snow, using a single image or a few successive images, without the need for specific elements in the scene, and weighting the results for accurate visibility indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LIDAR is used to evaluate transmission through the atmosphere for fog detection, then detection reliability is improved, but device cost increases significantly
Solution Approach 1:
The patent uses a camera to capture optical images of the scene, which serves as a copy or representation of the physical environment. This replaces the expensive LIDAR system with a much cheaper camera-based approach, achieving fog detection through image analysis rather than direct atmospheric transmission measurement
Solution Approach 2:
The patent replaces the active LIDAR mechanical system with a passive optical imaging system using a camera. The detection is performed through software-based image processing algorithms that analyze optical patterns, substituting mechanical/active sensing with optical/passive sensing combined with computational analysis
2Measurement precision
If targets are arranged in the scene for fog detection, then detection precision is improved, but ease of operation deteriorates due to installation constraints
Solution Approach 1:
The patent enables the camera system to detect fog using naturally occurring light sources in the scene (streetlights, vehicle lights, etc.) without requiring any additional targets or markers to be installed. The system serves itself by utilizing existing environmental elements for detection
Solution Approach 2:
The patent makes the fog detection system universal by not requiring scene-specific targets. The same camera system can detect fog in any environment with appropriate lighting, making the solution applicable to various locations without customization or installation of additional components
3Reliability
If halo detection around taillights is used for fog detection, then detection reliability is improved in certain conditions, but adaptability deteriorates when no vehicle lights are present
Solution Approach 1:
The patent enhances universality by detecting halos around any light source in the scene, not just vehicle taillights. This includes streetlights, building lights, and other illuminated objects, allowing the system to function reliably in diverse scenarios such as empty roads, different times of night, and various urban environments
Solution Approach 2:
The patent adapts to different operating conditions by adjusting detection parameters based on the scene. The system can switch between detecting halos around distant light sources (when no vehicles are present) and around vehicle lights (when vehicles are present), maintaining reliability across varying conditions through parameter adaptation
4Speed
If backscattering analysis of headlights is used for fog detection, then detection speed is improved, but reliability deteriorates in well-lit environments
Solution Approach 1:
The patent adapts the detection approach based on environmental lighting conditions. In well-lit environments, the system relies more on halo detection around visible light sources, while in darker environments with less ambient light, it can utilize backscattering analysis. The weighting parameters are adjusted dynamically based on scene illumination levels
Solution Approach 2:
The patent introduces an intermediary approach by combining multiple detection methods (halo detection and backscattering analysis) with a weighting mechanism. The system uses ambient light level analysis as an intermediary to determine the appropriate weighting between different detection techniques, ensuring reliability across various lighting 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
This approach provides a reliable and cost-effective method for detecting visibility disturbances under most circumstances, improving driving safety by quickly identifying fog and other elements, even in well-lit environments, using either monochrome or color cameras.
Implementation Method 1
at least one image of the scene is acquired with the help of a camera
Implementation Method 2
detecting the presence of a disturbing element in said at least one image or in a portion thereof as a function of the backscattering of light emitted by said stationary or swivel-mounted light source(s)
Implementation Method 3
detecting the presence of a disturbing element as a function of the halo appearing in said at least one image in the vicinity of said light source(s)
Data Source
AI summary
A method of detecting the presence of an element (fog, rain, etc. . . . ) disturbing the visibility of a scene illuminated by a headlight (105, 107) at night. The method comprises:a) acquiring an image of the scene with the help of a camera (120);b1) detecting the light sources in the image;b2) detecting the presence of the disturbing element as a function of the halo (H) appearing in the image in the vicinity of the light sources;c) detecting the presence of the disturbing element in the image as a function of the backscattering of the light emitted by the light sources; andd) weighting the results of the detections performed in steps b2) and c) in such a manner as to output an indication concerning the presence of the element disturbing the visibility of the scene.The method provides satisfactory results in an environment with or without lighting. The invention also provides a computer program and a device for implementing the method.