Optical Object Coordinate Determination via Dynamic Focus Scanning
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Solution Overview
Problem
Existing optical object measurement techniques, such as laser triangulation, are susceptible to disturbances, inaccurate, and time-consuming due to the need for precise compliance with the Scheimpflug condition, especially when measuring uneven surfaces or large workpieces.
Innovation Solution
The method involves capturing a focus scanning image with varying focus settings during a single exposure, allowing for the generation of an image with an enhanced depth of field, which enables precise measurement without mandatory adherence to the Scheimpflug condition, using a system with a radiation generating device and an image sensor that varies focus settings during exposure, and employing image processing algorithms to determine object coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise compliance with the Scheimpflug condition is required for accurate measurement, then measurement precision is improved, but device complexity and susceptibility to disturbances increase
Solution Approach 1:
The patent changes the focus parameter dynamically during exposure to create a focus scanning image. By varying the focus setting across multiple depths, the system captures information from different focal planes simultaneously, eliminating the need for precise Scheimpflug condition compliance while maintaining measurement accuracy through computational processing of the focus scanning data.
2Measurement precision
If the Scheimpflug condition must be precisely met for accurate measurements, then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent implements continuous focus scanning during a single exposure period, maintaining uninterrupted data capture across multiple focal depths. This continuous action allows the system to gather sufficient measurement information without requiring multiple separate adjustments or repositioning operations, thereby reducing total measurement time while preserving accuracy.
3Device complexity
If fixed focus settings are used to simplify the system, then device complexity is reduced, but measurement precision deteriorates on uneven surfaces
Solution Approach 1:
The patent introduces dynamic focus scanning that continuously varies the focus setting during exposure, transforming a static fixed-focus system into a dynamic multi-focus system. This dynamic approach allows the system to adapt to varying depths and surface irregularities automatically, maintaining measurement precision on uneven surfaces while keeping the physical system simple without requiring mechanical adjustments.
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 simplifies system setup, reduces susceptibility to disturbances, and achieves high measurement accuracy and speed, enabling uninterrupted scanning of workpiece surfaces with improved robustness against noise, even when the Scheimpflug condition is not met.
Implementation Method 1
Laser sensors emit electromagnetic radiation in the form of laser radiation having typically just a single defined wavelength or a single defined wavelength range. The incident radiation forms on the object surface a measurement region... The incident laser radiation is reflected and/or scattered by the object surface (or by the measurement points) and captured by a suitable capturing device of the sensor
Implementation Method 2
Next, a distance (or Z-value) between the capturing device and the object surface can be determined as distance information in a manner which is known per se. This can be accomplished using triangulation principles.
Implementation Method 3
The method involves capturing a focus scanning image with varying focus settings during a single exposure, allowing for the generation of an image with an enhanced depth of field
Data Source
AI summary
A system for optical measurement of an object includes a radiation generating device, a capturing device, and an evaluation device. The radiation generating device is configured to emit electromagnetic radiation onto the object. The capturing device includes an image sensor. The capturing device is configured to capture a measurement image as a result of an exposure of the image sensor with radiation returned from the object. The capturing device is configured to vary a focus setting (D) during the exposure. The evaluation device is configured to determine coordinates of at least one location on the object based on the captured measurement image.