White Balance Correction for Road Surface Recognition
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Solution Overview
Problem
Existing environment recognition systems face challenges in performing accurate white balance correction without response delay, particularly when dealing with roads that are not gray and under changing environmental light conditions, which can affect the detection of road surfaces and lead to inappropriate control responses.
Innovation Solution
An environment recognition device and method that include a data retaining unit, luminance obtaining unit, luminance specifying unit, white balance deriving unit, and white balance performing unit, which derive and maintain white balance correction values based on the luminance of a road surface and a reference portion, ensuring accurate recognition of the road surface color and maintaining previous correction values when the road surface changes, preventing response delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If white balance correction is performed to make the road surface gray, then the white balance accuracy is improved, but the response delay occurs when the road surface color changes
Solution Approach 1:
The patent applies dynamics by making the white balance correction value adaptive rather than static. The system dynamically adjusts the white balance correction based on detected road surface color changes. When a color change is detected (when the difference between current and previous road surface colors exceeds a threshold), the system updates the white balance correction value accordingly, allowing the system to respond to environmental changes without unnecessary delay while maintaining accuracy.
2Stability of the object's composition
If a low-pass filter is used to exclude roads with colors different from gray, then the white balance correction stability is improved, but the responsiveness to environmental light changes deteriorates
Solution Approach 1:
The patent replaces the static low-pass filter approach with a dynamic detection mechanism. Instead of continuously filtering out color variations, the system detects when road surface color changes exceed a predetermined threshold and only then updates the white balance correction. This dynamic approach maintains stability by ignoring minor fluctuations while responding to significant environmental changes, eliminating the trade-off between stability and responsiveness.
Solution Approach 2:
The patent changes the parameter used for white balance correction from a fixed filter-based approach to a variable approach based on detected color changes. The system monitors the difference between current and previous road surface colors and adjusts the white balance correction parameter accordingly. When the color difference exceeds a threshold, the parameter is updated; otherwise, it is maintained, allowing the system to adapt to environmental changes while maintaining stability.
3Measurement precision
If white balance correction is applied to colored road surfaces, then the color accuracy is improved, but the loss of white balance information in the detection area occurs
Solution Approach 1:
The patent extracts the road surface color information from the detection area to perform white balance correction separately. By identifying and extracting the road surface region, the system can determine its color characteristics and apply correction values without affecting the overall white balance information in the entire detection area. This allows accurate road surface color recognition while preserving the ability to detect other objects and their colors in the scene.
Data Source
AI summary
A environment recognition device obtains luminances of a target portion existing in an area specifies a road surface luminance and a reference portion luminance; when the road surface luminance changes by a predetermined value or more, the reference portion luminance does not change by another predetermined value or more, and the changed road surface luminance is not a predetermined color, maintains a white balance correction value prior to the change until the road surface luminance returns to the predetermined color, and, in other cases, derives a white balance correction value to recognize the road surface luminance as the predetermined color; derives a corrected luminance by performing a white balance correction using the white balance correction value on the obtained luminance; and provisionally determines a object corresponding to the target portion from a corrected luminance of the target portion based on an association of a luminance range and the specific object.