Multi-angle Lighting for Curved Surface Defect Detection
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Solution Overview
Problem
Conventional machine vision detection systems struggle with detecting surface defects on complex curved surfaces, such as steel rails and smoke collecting hoods, due to limited illumination modes and inability to obtain dense three-dimensional surface information, leading to high omission rates and low accuracy.
Innovation Solution
An automatic machine vision detection device with a camera and multiple light sources arranged on a detection unit bracket, where light sources are sequentially activated to illuminate the workpiece from different angles, allowing for non-overlapping strongest illumination areas and enabling the capture of multiple images for fusion into a normal map to reconstruct the surface texture, thereby enhancing defect detection and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lighting solution is used for machine vision detection, then the device complexity is reduced, but the detection accuracy and defect presentation are insufficient for complex curved surfaces
Solution Approach 1:
The lighting device is segmented into multiple independent light sources (first light source, second light source, third light source) positioned at different locations and angles. Each light source independently illuminates the workpiece from a specific direction, allowing the system to capture different defect types that would be invisible under a single lighting condition.
Solution Approach 2:
Different regions of the workpiece surface receive different lighting conditions tailored to reveal specific defect types. The first light source illuminates for general surface defects, the second light source targets inclined surface defects, and the third light source highlights curved surface defects, creating locally optimized illumination quality for each detection zone.
2Measurement precision
If multiple light sources are used to illuminate from different angles, then the defect detection accuracy is improved, but the device complexity increases
Solution Approach 1:
Multiple light sources and the camera are merged into an integrated detection device structure. The first light source, second light source, and third light source are combined with the camera in a coordinated arrangement, allowing simultaneous multi-angle illumination and image capture without requiring separate complex systems.
Solution Approach 2:
The detection device is designed with multi-functionality to handle various workpiece types (flat surfaces, inclined surfaces, curved surfaces) and defect types using a single integrated system. The multiple light sources provide universal coverage for different inspection scenarios, eliminating the need for multiple specialized devices.
3Illumination intensity
If light sources are positioned close to the workpiece, then the illumination intensity is increased, but the illumination areas overlap and reduce detection effectiveness
Solution Approach 1:
The light sources are positioned asymmetrically at different distances and angles from the workpiece. The first light source is positioned at a standard distance for general illumination, while the second and third light sources are positioned at inclined angles and different distances to create non-overlapping illumination zones that target specific surface regions and defect types.
Solution Approach 2:
The lighting configuration transitions from one-dimensional (single direction) to three-dimensional multi-angle illumination. The light sources are arranged in different spatial dimensions (horizontal angles and vertical angles), creating illumination areas that complement rather than overlap, thereby enhancing defect detection across different surface orientations.
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 presents various surface defect types and achieves high detection accuracy by fusing spatial and inter-frame information, reducing interference from highlights and improving defect detection rates, enabling full-automatic qualitative and quantitative surface quality inspection of complex curved surfaces.
Implementation Method 1
the strongest illumination areas of the light sources in the same detection unit on the to-be-inspected object are not overlapped with one another
Data Source
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AI summary
The present invention discloses an automatic machine of vision detection device for a workpiece with a complex curved surface, wherein the system is provided with at least one defect detection unit, the defect detection unit comprises a camera, light sources and an detection unit bracket; the camera and the light sources are arranged on the detection unit bracket; one camera and a plurality of light sources configured for the camera are used as one detection unit, the distance between the light source and a to-be-inspected workpiece is five times greater than the shooting field of view of the camera, when the same detection unit performs a shooting task, the light sources are sequentially lightened, when the light sources are lightened once, the camera shoots an image of the to-be-inspected object once, only one light source is lightened when the camera shoots each time, and the strongest illumination areas of the light sources in the same detection unit on the to-be-inspected object are not overlapped with one another.