Optical Measuring Apparatus with Diffuser Plates for Glossy Defect Detection
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Solution Overview
Problem
Existing inspection devices for car paint surfaces struggle with accurately detecting defects on glossy, curved surfaces using three-dimensional shape measurement methods, particularly due to uneven illumination patterns and interference from multiple frequency and color components.
Innovation Solution
A measuring apparatus with a specific optical configuration including an illuminator, diffuser plates, and a light shield, which forms a uniform sinusoidal illumination pattern to enhance specular reflection for accurate defect detection on glossy, curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple frequency and color components are combined to create pattern light for three-dimensional shape measurement, then the measurement capability is enhanced, but illumination uniformity deteriorates and interference increases
Solution Approach 1:
The patent segments the illumination system into multiple independent light sources (blue, green, red LEDs) arranged in arrays, with separate control for each color and frequency component. This allows individual optimization of each component while maintaining overall uniformity, resolving the contradiction between measurement capability and illumination uniformity.
Solution Approach 2:
The patent applies local quality by positioning light sources at specific locations and angles to illuminate different regions of the object surface uniformly. Each light source is strategically placed to contribute to uniform illumination in its local area, while the combined effect achieves overall uniformity across the entire measurement area.
2Adaptability or versatility
If pattern light with multiple frequency and color components is projected onto the object, then three-dimensional shape measurement is enabled, but defect detection precision deteriorates due to interference
Solution Approach 1:
The patent segments the optical measurement into separate channels for different color and frequency components, allowing independent processing and analysis. This segmentation enables the system to distinguish between surface geometry information and defect characteristics, improving defect detection precision while maintaining three-dimensional shape measurement capability.
Solution Approach 2:
The patent utilizes color changes by employing multiple LED light sources with different wavelengths (blue, green, red) to illuminate the object. Different colors enhance different surface properties and defect characteristics, allowing the system to optimize detection for specific defect types while maintaining comprehensive shape measurement.
3Device complexity
If conventional illumination is used for glossy, curved surfaces, then the setup is simple, but specular reflection interference causes inaccurate defect detection
Solution Approach 1:
The patent segments the illumination into multiple directional components with different angles and colors, allowing control over the specular reflection patterns. This segmented approach enables the system to minimize harmful reflections while maintaining simple overall setup, improving defect detection accuracy on glossy surfaces.
Solution Approach 2:
The patent applies parameter changes by adjusting the angles, colors, and intensities of individual light sources to optimize illumination conditions for glossy, curved surfaces. By dynamically controlling these parameters, the system minimizes specular reflection interference and maximizes defect visibility, maintaining simple setup while improving measurement precision.
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 apparatus achieves highly accurate measurement and detection of defects such as scratches, cracks, and unevenness on painted vehicle surfaces by minimizing illumination pattern irregularities and improving specular reflection, thereby enhancing defect detection precision.
Implementation Method 1
a first diffuser plate, a second diffuser plate between the first diffuser plate and the object
Implementation Method 2
a light shield portion between the second diffuser plate and the object and having an opening
Implementation Method 3
a light receiver to receive light specularly reflected from the object illuminated by the illuminator
Data Source
AI summary
A measuring apparatus includes an illuminator including a light source to emit light onto an object being conveyed in a conveyance direction; a first diffuser plate; a second diffuser plate between the first diffuser plate and the object; a light shield portion between the second diffuser plate and the object; and a light receiver to receive light specularly reflected from the object illuminated by the illuminator. The light shield portion has an opening that includes an optical axis of light emitted from the light source and reaching the second diffuser plate.