Optical Imaging Device Wavelength Sensitivity for Short-Range Detection
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Solution Overview
Problem
Existing driver assistance systems face challenges in efficiently detecting objects at short distances without wasting processing resources or causing erroneous decisions due to false detections at longer distances, particularly in daylight conditions.
Innovation Solution
Pre-setting the maximum sensitivity of the optical imaging device to a wavelength range where transmittance in air is significantly lower, such as between 5 µm and 8 µm, reduces the detection of objects at larger distances, allowing image processing algorithms to focus on closer objects with enhanced reliability and efficiency without additional processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the camera detects objects at larger distances, then the detection range is extended, but processing power is wasted and false detections increase
Solution Approach 1:
The patent applies local quality by making different parts of the optical spectrum serve different functions. Specifically, it uses a first spectral range (e.g., visible light) for long-range detection and a second spectral range (e.g., infrared) for short-range detection. This allows the system to process images at different wavelengths separately, enabling efficient filtering of distant objects using the visible range while focusing processing resources on nearby objects using the infrared range, thereby reducing wasted processing power.
2Measurement precision
If the camera focus is adjusted to short distance, then near-sighted detection is achieved, but processing power is still wasted on distant objects
Solution Approach 1:
The patent applies parameter changes by switching between different spectral parameters. Instead of adjusting mechanical focus, it changes the wavelength parameter of the detected light. By capturing images in both visible and infrared spectral ranges and comparing them, the system can identify distant objects that appear in the visible range but not in the infrared range, then exclude these from further processing, thereby reducing processing power consumption while maintaining high short-range detection accuracy.
3Measurement precision
If computational photography techniques are used to estimate distance, then object distance assessment is improved, but hardware cost and complexity increase
Solution Approach 1:
The patent uses the atmospheric medium itself as an intermediary to provide distance information. By exploiting the fact that atmospheric scattering and absorption affect visible and infrared light differently with distance, the system lets the atmosphere naturally encode range information in the image data. Comparing images from the two spectral ranges allows the system to infer distance without requiring active illumination or complex depth-sensing hardware, thus avoiding increased device complexity while maintaining distance estimation accuracy.
4Illumination intensity
If active illumination systems are used, then short-range object contrast is enhanced, but ambient light interference occurs in daylight
Solution Approach 1:
The patent applies another dimension by transitioning from the visible light dimension to the infrared dimension for detection. Since ambient daylight primarily affects the visible spectrum, using infrared imaging provides a separate dimensional channel that is largely immune to sunlight interference. The system captures infrared images where thermal radiation from objects provides contrast independent of visible light conditions, thereby enhancing short-range object detection without suffering from ambient light interference.
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 enables reliable short-range object detection with reduced processing resources, improving image quality and detection speed for critical proximity scenarios like pedestrian detection, while being cost-effective by minimizing hardware changes to the optical imaging device.
Implementation Method 1
an optical imaging device (12) having a sensitivity in the wavelength range between 5 µm and 8 µm, wherein the transmittance in air at a wavelength between 5 µm and 8 µm is significantly lower than at a maximum transmittance in the same order of magnitude wavelength range
Implementation Method 2
By pre-setting the maximum sensivity of the optical imaging device (12) to a wavelength where the transmittance in air is significantly lower than at a maximum transmission wavelength in the same order of magnitude wavelength range, objects at larger distances get a low contrast and therefore become unlikely to be detected by the image processing algorithms
Data Source
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AI summary
A driver assistance system (10) for a motor vehicle comprises at least one optical imaging device (12) adapted to take images from a surrounding of a motor vehicle, a processing means (14) adapted to perform image processing of images taken by said imaging device (12), and a driver assistance and/or safety means (18) controlled by said processing means (14) depending on said image processing. The maximum sensivity of said optical imaging device (12) is pre-set to a wavelength where the transmittance in air is significantly lower than at a maximum transmission wavelength in the same order of magnitude wavelength range.