Annular Surface Inspection Using Directional Line Illumination
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Solution Overview
Problem
Conventional visual inspection systems fail to detect shallow dents or scratches on the mirror-like surface of annular products due to the lack of significant light reflection differences between normal and defective portions, as they use non-directional uniform diffused illumination light.
Innovation Solution
A visual inspection system employing a holding unit, a rotation drive unit, a first illumination unit with a line-shaped light projector, a line sensor camera, and a judgment device to capture and process images of annular products, utilizing filmy illumination light with directional properties to highlight defects like dents or scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If non-directional uniform diffused illumination light is used, then the illumination covers the entire surface uniformly, but the light reflection difference between normal and defective portions is not significant, making defect detection difficult
Solution Approach 1:
The patent applies local quality by using a line-shaped light projector that radiates filmy illumination light in a specific direction rather than uniform diffused light. This directional illumination creates localized reflection patterns that differ significantly between normal and defective portions of the mirror-like surface, enabling defect detection while maintaining adequate illumination coverage.
Solution Approach 2:
The patent changes the illumination parameters from non-directional uniform diffused light to directional filmy illumination light. This parameter change in light direction and distribution creates significant light reflection differences between normal and defective areas, solving the contradiction between illumination uniformity and defect detection capability.
2Shape
If the product has a mirror-like surface with fine surface roughness, then the aesthetic quality is improved, but shallow dents or scratches are difficult to detect due to lack of light reflection differences
Solution Approach 1:
The line-shaped light projector creates localized directional illumination that interacts differently with normal versus defective portions of the mirror-like surface. This local quality approach to illumination reveals shallow dents and scratches that would be invisible under uniform diffused light, while the product maintains its aesthetic mirror-like finish.
Solution Approach 2:
By changing the illumination parameters to directional filmy light instead of uniform diffused light, the system creates detectable light reflection differences on mirror-like surfaces without altering the product's surface finish quality. This parameter change enables detection of shallow defects while preserving aesthetic appearance.
3Adaptability or versatility
If multiple illumination units with different colors are used, then the inspection coverage is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple illumination functions into a single line-shaped light projector that radiates filmy illumination light. This unified approach provides comprehensive inspection coverage with directional light that highlights defects, avoiding the need for multiple separate illumination units and reducing overall system complexity.
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 system effectively detects shallow dents or scratches on mirror-like surfaces by producing a significant difference in light reflection between normal and defective areas, enabling reliable defect detection.
Implementation Method 1
the first illumination unit has a line-shaped light projector disposed along a radial direction of the annular product, and radiates a filmy illumination light radiated from the light projector to an outside surface of the annular product to illuminate the outside surface of the annular product
Data Source
AI summary
The present invention includes a holding unit holding an annular product, a rotation drive unit causing the holding unit holding the annular product to rotate about a center axis of the annular product, a first illumination unit having a line-shaped light projector along a radial direction of the annular product and radiating a filmy illumination light from the light projector to an outside surface of the annular product, a line sensor camera having a line-shaped light receiving unit and arranged such that the light receiving unit is parallel to the light projector and imaging, from a direction identical to the radiating direction of the first illumination unit, the outside surface of the annular product illuminated by the first illumination unit as a region to be imaged, and a judgment device processing an image captured by the line sensor camera to judge whether the annular product is defective in appearance.