Monochrome Camera Color Discrimination via Spectral Segmentation
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Solution Overview
Problem
Black and white lane departure warning systems struggle to distinguish between white and colored road markings due to susceptibility to ambient light changes and faded paint, making it difficult to differentiate between various colored lines.
Innovation Solution
A method and apparatus using a monochrome camera with different color responses in its field of view, capturing images and determining the change in intensity between areas to discriminate between road markings, employing filter means with sections of varying absorbance spectra to differentiate between colors like yellow, red, and blue, allowing the system to determine road marking colors without a color camera.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a black and white monochrome camera is used to reduce system cost, then economy is improved, but the ability to discriminate between different colored road markings deteriorates
Solution Approach 1:
The field of view of the monochrome camera is divided into multiple spectral response areas, each sensitive to different wavelength ranges. This segmentation allows the single camera to capture multiple spectral bands simultaneously, enabling color discrimination without requiring multiple cameras or a color camera.
Solution Approach 2:
Different areas of the camera's field of view are given different spectral sensitivities through the use of a dichroic beamsplitter and multiple sensors. Each sensor area is optimized to detect specific wavelength ranges, creating local quality variations that enable color differentiation while using a single monochrome camera.
2Device complexity
If absolute intensity is used to distinguish between white and other color lines, then simplicity is improved, but reliability deteriorates due to susceptibility to ambient light changes and faded paint
Solution Approach 1:
Instead of relying on absolute intensity values that vary with lighting conditions, the system changes the measurement parameter to spectral ratio or relative intensity between different wavelength bands. This ratio-based approach cancels out the effects of ambient light changes and paint fading, maintaining reliability while keeping the detection method relatively simple.
3Measurement precision
If filter means with different absorbance spectra are used to provide different color responses, then color discrimination ability is improved, but device complexity increases
Solution Approach 1:
A dichroic beamsplitter is introduced as an intermediary optical element that automatically separates incoming light into different wavelength bands and directs them to appropriate sensors. This intermediary component performs the spectral separation function that would otherwise require complex filter assemblies for each sensor, simplifying the overall device structure while maintaining high color discrimination ability.
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
Enables effective discrimination between different colored road markings, improving the accuracy of lane detection and edge recognition, especially in low-intensity differences, and can be integrated into automotive guidance systems like lane departure warning systems.
Implementation Method 1
capturing an image of a road and at least one road marking with a monochrome camera having a first colour response in a first area of a field of view of the camera and a second colour response in a second area of the field of view; and determining the change in intensity of the captured image of the road marking between the first and second areas
Implementation Method 2
The step of capturing the image may comprise viewing the image through filter means, wherein sections of the filter means of different absorbance spectra provide the different colour response of the first and second areas
Data Source
AI summary
A method of discriminating between road markings of at least two colors, comprises: capturing an image of a road and at least one road marking with a monochrome camera having a first color response in a first area of a field of view of the camera and a second color response in the second area of the field of view; and determining the change in intensity of the captured image of the road marking between the first and second areas. Apparatus for discriminating between road markings is also disclosed.