Optical Module Rain Detection via Dual-Path Sensor
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Solution Overview
Problem
Existing optical modules for vehicle assistance systems struggle to accurately determine rain intensity due to the inability to focus on both distant vehicle surroundings and the windshield area simultaneously, leading to potential false detection and inefficient windshield wiper operation.
Innovation Solution
An optical module with a camera and lens system that focuses on both far-range vehicle surroundings and a close-up area of the windshield using a single camera, incorporating an optical arrangement with a mirror and light source to isolate the windshield area for precise rain detection, and an image evaluation unit to control the windshield wiper interval based on detected objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used to observe both far area and pane area, then device complexity is reduced, but the ability to simultaneously focus on both areas is compromised
Solution Approach 1:
The optical arrangement includes a mirror that redirects light from the pane detection area to the camera, effectively adding a spatial dimension to the optical path. This allows the single camera to receive light from two different focal planes (far area and pane area) simultaneously by utilizing different spatial paths, thereby maintaining simultaneous focusing capability while using only one camera.
2Measurement precision
If the optical arrangement focuses on objects a few centimeters in front of or behind the pane, then raindrop detection precision is improved, but the depth of field becomes very shallow
Solution Approach 1:
The optical arrangement is designed to create a localized shallow depth of field specifically for the pane detection area, while the main lens maintains its deep depth of field for the far area. By directing light from the pane area through a separate optical path with its own focusing characteristics, the system achieves high local quality (sharp focus) for raindrop detection without compromising the overall system's ability to handle various depth ranges.
3Adaptability or versatility
If the second section of the sensor surface is used for rain detection, then core functionality (lane recognition, traffic sign recognition) is maintained, but the area available for rain detection is limited
Solution Approach 1:
The camera system is designed with multi-functionality, where the same camera and sensor surface serve multiple purposes: the first section of the sensor surface handles core functionality (lane recognition, traffic sign recognition, night vision), while the second section simultaneously handles rain intensity determination. This universal design allows the system to perform multiple functions with a single device, maximizing the utility of the limited sensor area.
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 precise and reliable rain intensity determination, optimizing windshield wiper operation by distinguishing raindrops from other objects and reducing false triggering, while maintaining a compact design and core functionality integrity.
Implementation Method 1
an optical arrangement which is arranged in the field of view of the camera and through which a close-up area comprising a detection area of the pane can be sharply imaged on a second section of the sensor surface of the camera
Implementation Method 2
the optical arrangement comprises a mirror, which directs light emerging from the detection area of the pane through the lens and into the camera
Implementation Method 3
a light source is provided for illuminating the detection area of the pane in order to enable objects located on the pane to be detected even at night
Data Source
Figure 1~2
AI summary
The module has a camera (10) e.g. greyscale camera, arranged at an inner side (14) of a windshield (16) having a field of vision directed through the windshield towards an ambient region about a motor vehicle. The camera comprises a flat-panel sensor with a sensor surface (13), and an objective (12) arranged with the sensor surface for focusing a distant region on a main section to create a sharp image. An optical assembly is arranged in a field of vision and provided for focusing a detection region (20) on an auxiliary section to create the sharp image. An independent claim is also included for a method for controlling a wiping interval of a windshield wiper of a motor vehicle.