3D Camera Dirt Detection Using Time-of-Flight Sensor Reflections
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Solution Overview
Problem
Camera devices with 3D-Time-of-Flight sensors face issues with dirt accumulation on the transparent cover of the light guide, leading to impaired image quality and costly service interruptions, as existing dirt detection systems are complex, costly, or designed for specific environments like headlamps or windshields.
Innovation Solution
A 3D-camera device with a Time-of-Flight sensor and a dirt detection unit that emits light at a predetermined angle to reflect dirt back through the transparent cover, allowing the Time-of-Flight sensor to accurately detect dirt by distinguishing it from background light, using a control unit to synchronize light pulses and exposures for precise dirt detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed housing is used to protect the camera device in dirty environments, then the device reliability is improved, but dirt accumulates on the transparent cover and impairs image quality
Solution Approach 1:
The patent applies preliminary action by implementing a dirt detection unit that proactively monitors the transparent cover for dirt accumulation before it significantly degrades image quality. The system detects dirt particles, rain drops, or other contaminants on the cover surface and triggers a cleaning operation in advance, preventing the harmful effect of dirt accumulation while maintaining the sealed housing protection.
2Measurement precision
If existing dirt detection systems are used (designed for headlamps or windshields), then dirt detection capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies universality by adapting the Time-of-Flight sensor, originally designed for 3D imaging, to perform dual functions: both capturing depth information and detecting dirt on the transparent cover. The same sensor array and processing unit are used for both primary imaging and contaminant detection, eliminating the need for separate dedicated detection hardware and reducing overall system complexity.
Solution Approach 2:
The patent applies copying by using the existing Time-of-Flight sensor infrastructure to create a virtual representation of the transparent cover surface. The sensor captures light reflections from the cover, and the processing unit generates an image or data representation that replicates the cover surface state, allowing dirt detection without additional physical sensors.
3Measurement precision
If the Time-of-Flight sensor is used for dirt detection by emitting light at a predetermined angle, then dirt detection accuracy is improved, but the system must distinguish dirt reflections from background light
Solution Approach 1:
The patent applies local quality by directing light at a specific predetermined angle that creates a localized reflection pattern characteristic of dirt particles on the transparent cover. This angled illumination causes dirt to reflect light in a distinct direction different from the surrounding background, creating a spatially differentiated signal that the sensor can identify and isolate from general background light.
Solution Approach 2:
The patent applies periodic action by emitting light pulses in a periodic manner and synchronizing the sensor activation with these pulses. The control unit coordinates the light emission and sensor measurement cycles, allowing the system to distinguish between light reflected from dirt (occurring at specific pulse intervals) and continuous background light, thereby improving detection accuracy through temporal discrimination.
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
The solution provides a reliable, cost-effective, and accurate dirt detection system that increases operational reliability and reduces service interruptions by isolating light reflections from dirt, ensuring continuous camera functionality in dirty environments.
Implementation Method 1
the emitted light is directed in a predetermined angle (A) such that at least a portion of the emitted light is reflected out through a second portion of the transparent cover by dirt present on the outer surface of the transparent cover
Data Source
AI summary
A 3D-camera device (1) comprising a Time-Of-Flight sensor (5) and a light guide (4) with a light transparent cover (3). A light source (6) is arranged to emit light (7) into the transparent cover (3), whereby at least a portion (10) of the emitted light (7) is reflected out through a second portion (3.1) of the transparent cover (3) by dirt (100) present on the outer surface (3.20) of the transparent cover (3). The Time-Of-Flight sensor (5) is arranged to receive light (10) reflected by dirt (100) on the outer surface (3.20) of the transparent cover (3) and to output a signal (L) relative the amount of received reflected light (10). A control unit (20) configured to determine the presence of dirt (100) on the outer surface (3.20) of the transparent cover (3) from the magnitude of the signal (L) from the Time-Of-Flight sensor (5).