Particle-Blasted Surface Coverage Assessment by 3D Optical Thresholding
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Solution Overview
Problem
Existing methods for assessing the degree of coverage on particle-blasted surfaces, such as in the aviation industry, suffer from low accuracy, flexibility, robustness, and repeatability, particularly when determining the portion of the surface covered by the particle beam, leading to significant measurement errors.
Innovation Solution
A method using optical measurement techniques, such as white light interferometry, to record the surface in a spatially resolved manner, determine local gradients, and compare these with predetermined threshold values to identify areas not hit by the particle beam, thereby calculating the uncovered surface portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection by magnifying glass or pocket microscope is used, then the method is simple and low-cost, but the measurement precision and repeatability are low
Solution Approach 1:
The patent replaces manual visual inspection with optical measurement methods. Specifically, it uses white light interferometry to capture surface topography and automatically identifies impact craters through image processing algorithms, eliminating the need for manual magnification and visual assessment while dramatically improving measurement precision and repeatability.
Solution Approach 2:
The patent creates a digital 3D copy of the surface topography through optical scanning. By generating a precise digital model of the surface including all impact craters, the system enables repeated, consistent measurements without physical contact or manual intervention, thereby improving both accuracy and repeatability.
2Measurement precision
If fluorescent paint is applied before blasting, then the degree of coverage can be determined under UV light, but the method lacks accuracy and introduces additional processing steps
Solution Approach 1:
The patent extracts the measurement function from the surface treatment process itself. Instead of using fluorescent paint as a marker, the method directly measures the surface topography changes caused by particle impact, separating the blasting operation from the measurement operation and eliminating unnecessary chemical additives.
Solution Approach 2:
The surface itself serves as the measurement indicator. The impact craters created by particle blasting naturally alter the surface topography, which the optical system detects directly. The surface provides its own measurement signal through the physical deformation it undergoes during blasting, eliminating the need for external markers or coatings.
3Adaptability or versatility
If tactile measurement methods are used to create surface maps, then the degree of coverage can be determined, but the measurement precision and flexibility are limited
Solution Approach 1:
The patent replaces tactile mechanical measurement with optical measurement. Instead of physically touching the surface with a probe, the system uses white light interferometry to capture surface topography optically, providing non-contact measurement that is both more precise and more flexible for different surface geometries and accessibility requirements.
Solution Approach 2:
The patent transitions from 2D tactile line scanning to 3D optical surface mapping. By capturing the complete surface topography in three dimensions, the system provides comprehensive coverage assessment that is both more accurate and more versatile for complex surface geometries compared to linear tactile measurement.
4Measurement precision
If 3D surface recording by white light interferometer is used, then high measurement precision is achieved, but the device complexity and measurement time increase
Solution Approach 1:
The patent uses automated image processing algorithms that efficiently analyze the interferometric data to identify impact craters. The algorithm processes the surface map automatically, applying thresholding and morphological operations to distinguish craters from other surface features, thereby reducing manual analysis time while maintaining high measurement precision.
Solution Approach 2:
The system incorporates automated feedback through image processing algorithms that continuously refine the identification of impact craters. The algorithm analyzes the surface topography data, identifies characteristic crater patterns, and automatically calculates coverage metrics, providing rapid feedback that reduces overall measurement time while maintaining accuracy.
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 significantly reduces measurement errors, ensuring precise and repeatable determination of surface coverage, even near complete coverage levels, with an error margin of 0.02% for 98% coverage, and allows for automated, high-resolution 3D surface mapping.
Implementation Method 1
by means of an optical measuring method, in particular by means of white light interferometry, the surface machined by means of particle blasting is recorded in a spatially resolved manner
Data Source
AI summary
Methods for assessing the result of a surface treatment carried out on a workpiece by particle blasting are disclosed. It is generally common to known automatic methods that they directly determine the covered portion of the surface. Proceeding from the usual definition of the usual 98% degree of coverage as “completely blasted” results in an error in the determination of the corresponding area of 1% to a distortion of the measurement result by 0.98%. In the disclosed method measuring points are identified as not hit by a particle of the particle beam when both a detected surface level is above a level located about a predetermined height threshold value lower than a target level, and a detected gradient falls below a predetermined gradient threshold value.