Vessel Bottom Inspection Using Structured Illumination Scanning
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Solution Overview
Problem
Existing methods for inspecting the bottoms of translucent or transparent containers, such as glass vessels, suffer from measurement errors due to relative rotation between the vessel and camera, particularly with non-circular shapes, leading to difficulties in detecting small defects like shards.
Innovation Solution
A method using a matrix camera with structured illumination, where the illumination structure is shifted relative to the vessel's bottom between individual images, maintaining rotational invariance between the camera and vessel, and employing software to assemble a digital image from these images, optionally with AI assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the vessel rotates during inspection to capture multiple images, then the coverage area increases, but measurement precision deteriorates due to centrifugal forces displacing small defects
Solution Approach 1:
The inspection process is segmented into multiple stationary captures instead of one rotating capture. The vessel remains stationary while the illumination structure rotates in discrete steps, capturing different sectors sequentially. This eliminates centrifugal forces during capture while achieving complete coverage through segmented, sequential imaging.
Solution Approach 2:
Instead of rotating the vessel to achieve coverage, the illumination structure is rotated while the vessel remains stationary. This inverted approach maintains defect position stability during capture while still achieving comprehensive inspection coverage through the rotating illumination pattern.
2Adaptability or versatility
If the vessel rotates during inspection, then all areas can be inspected, but reliability decreases due to measurement errors from non-circular shapes
Solution Approach 1:
The rotation is applied to the illumination structure rather than the vessel. This inversion allows complete area coverage while maintaining the vessel in a stable, non-rotating position, eliminating measurement errors caused by centrifugal forces on non-circular shapes.
Solution Approach 2:
The system transitions from a static illumination structure to a dynamically rotating one. The illumination structure rotates during inspection to cover all vessel areas, while the vessel itself remains stationary, combining dynamic illumination with static object positioning for both completeness and accuracy.
3Measurement precision
If the vessel is stationary during inspection, then measurement precision improves, but productivity decreases due to longer inspection time
Solution Approach 1:
The illumination structure performs periodic rotation in discrete steps during inspection. It rotates to a new angular position, captures an image, then rotates to the next position. This periodic action enables complete coverage through multiple captures while maintaining the vessel stationary throughout, preserving both precision and throughput.
Solution Approach 2:
The illumination structure is made dynamic and rotatable while the vessel remains static. This allows the system to achieve complete inspection coverage through the moving illumination pattern without compromising measurement precision, thereby maintaining productivity despite the stationary vessel requirement.
4Reliability
If multiple individual images are captured and assembled, then defect detection reliability improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical rotation of the vessel with a simpler rotating illumination structure. Multiple individual images are captured by rotating the light source and assembling them computationally, substituting mechanical complexity with optical and software solutions to achieve high reliability.
Solution Approach 2:
The inspection is segmented into multiple individual image captures taken at different illumination angles. These segmented captures are then assembled into a complete inspection result. This segmentation approach improves reliability by capturing defects from multiple perspectives while using modular, manageable image processing steps.
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 reduces measurement errors, enhances defect detection accuracy, and allows inspection of non-circular vessels by eliminating centrifugal forces that displace small defects, thereby improving the reliability and range of applications.
Implementation Method 1
the base of the vessel is capable, in the broadest sense, of transmitting electromagnetic waves (especially in the visible spectral range) completely or at least partially
Implementation Method 2
the illumination structure is shifted relative to the bottom of the vessel between two individual images, and that the vessel and the matrix camera remain rotationally invariant relative to each other
Implementation Method 3
a series of individual images of areas of the bottom of the vessel are taken... A digital image of the bottom of the vessel is assembled from the series of individual images
Data Source
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AI summary
A method for generating an image (A) of a translucent or transparent bottom (5) of a vessel (3) uses a matrix camera (39) with pixels (40) arranged in a plurality of rows (Z) and a plurality of columns (S). The matrix camera (39) takes a series of individual images (E) of sections B) of the bottom (5) of the vessel (3), which overlap section by section, while the bottom (5) of the vessel (3) is illuminated by a light source (37) located on the side opposite the matrix camera (39). A digital image (A) of the bottom (5) of the vessel (3) is assembled from the individual images (E).The invention is characterized in that the area (B) of the bottom (5) of the vessel (3) recorded in a single image (E) is defined by an illumination structure (50), that the illumination structure (50) is shifted relative to the bottom (5) of the vessel (3) between two single images (E), and that the vessel (3) and the matrix camera (39) remain rotationally invariant relative to each other during the recording of the series of single images (E). The invention also relates to a device (24) for carrying out the method.