Optical Sensor With Tunable Aperture for Accurate Height Profiles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical sensors face challenges in accurately detecting 2D or 3D height profiles of object surfaces due to artifacts such as side lines or multiple reflections caused by varying surface properties, particularly on glossy surfaces.
Innovation Solution
The optical sensor incorporates a tuneable aperture in the receiving optics, controlled by an evaluation unit based on image parameters, to adapt the aperture size and shape to compensate for image artifacts and improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the aperture of the receiving optics is kept fixed, then the device complexity is reduced, but the detection precision deteriorates due to image artifacts on glossy surfaces
Solution Approach 1:
The patent applies the dynamics principle by implementing a tuneable aperture that can dynamically adjust its opening size based on detected image artifacts. The aperture transitions from a fixed state to a controllable variable state, allowing the system to adapt to different surface properties (glossy vs. diffuse) and eliminate artifacts like side lines and double lines while maintaining accurate height profile detection.
Solution Approach 2:
The patent applies parameter changes by modifying the aperture opening parameter in response to detected image quality. The evaluation unit analyzes image parameters and controls the aperture to change its opening size, thereby altering the optical parameters of the receiving optics to compensate for artifacts and improve measurement precision across varying surface conditions.
2Illumination intensity
If the aperture size is increased to capture more light, then the illumination intensity is improved, but image artifacts such as side lines and multiple reflections are enhanced
Solution Approach 1:
The system dynamically adjusts the aperture size based on the detected surface properties. For glossy surfaces that generate artifacts, the aperture is reduced to eliminate side lines and reflections. For diffuse surfaces, the aperture can be opened wider to maximize light capture. This dynamic adaptation allows the system to optimize the brightness-artifact trade-off in real-time.
Solution Approach 2:
The aperture opening parameter is changed in response to image analysis results. When artifacts are detected, the aperture parameter is reduced to decrease artifact intensity. When no artifacts are present, the aperture is opened to maximize light capture, thereby optimizing the brightness signal for accurate detection.
3Measurement precision
If the aperture is reduced to eliminate artifacts, then the image quality is improved, but the amount of captured light is reduced
Solution Approach 1:
The system dynamically adapts the aperture size to the specific measurement conditions. Rather than using a fixed small aperture that would always limit light, the system opens the aperture wide for diffuse surfaces to maximize brightness, and only reduces it when artifacts are detected from glossy surfaces. This dynamic approach ensures optimal brightness is captured whenever possible.
Solution Approach 2:
The aperture parameter is adjusted based on real-time image analysis. For diffuse surfaces, the aperture parameter is set to maximum to capture sufficient light. For glossy surfaces with artifacts, the parameter is reduced to eliminate artifacts. This conditional parameter adjustment optimizes the brightness-quality trade-off for each specific measurement scenario.
4Adaptability or versatility
If a fixed aperture is used, then the ease of operation is improved, but the adaptability to different surface properties deteriorates
Solution Approach 1:
The system applies self-service by using the evaluation unit to automatically analyze captured images for artifacts and autonomously control the aperture adjustment. The system self-regulates without requiring manual intervention or external control, adapting to different surface properties (glossy vs. diffuse) automatically. This maintains ease of operation while achieving high adaptability.
Solution Approach 2:
The system implements feedback control where the evaluation unit analyzes image parameters from captured light line images and uses this feedback to automatically adjust the aperture. The closed-loop control adapts the aperture setting based on detected surface properties, providing both adaptability to different objects and automated operation that maintains ease of use.
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 enhances detection accuracy by selectively blurring unwanted side peaks or lines, allowing for precise determination of the object's height profile even with varying surface properties.
Implementation Method 1
a receiving optics arranged upstream of the light receiver for generating an image of the at least one projected light onto the light receiver
Implementation Method 2
a light transmitter which is configured to project at least one light line onto the object surface
Implementation Method 3
a light receiver having an array of receiving elements
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to an optical sensor for the detection of at least one height profile of an object surface in accordance with the principle of light sectioning method. The optical sensor comprises a light transmitter which is configured to project at least one light line onto the object surface, a receiving unit comprising a light receiver having an array of receiving elements and a receiving optics arranged upstream of the light receiver for generating an image of the at least one projected light onto the light receiver, and an evaluation unit connected to the light receiver and configured for determining the height profile from an image of the at least one projected light line recorded by the light receiver. The receiving unit further comprises a tuneable aperture associated with the receiving optics and configured for varying the size and/or the shape of the aperture of the receiving optics, wherein the evaluation unit is configured for controlling the tuneable aperture in dependence from at least one image parameter of the image of the at least one projected light line.