Dual-Camera Inspection for Cylindrical Surface Defect Detection
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Solution Overview
Problem
Existing methods for inspecting and printing on cylindrical objects lack precision and efficiency in ensuring complete coverage and quality of the surface, particularly in inkjet printing, where defects and errors can go undetected.
Innovation Solution
A dual-camera system with a line camera for linear scanning and a matrix camera for two-dimensional scanning, synchronized with the rotational speed of the cylindrical object, to ensure complete surface coverage and detect defects, coupled with an inkjet printing device that adjusts ink delivery based on inspection results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single camera with line scanning is used, then the scanning speed is high, but the measurement precision and defect detection capability are insufficient
Solution Approach 1:
The inspection system is segmented into two functional parts: a line camera for high-speed scanning and a matrix camera for high-precision inspection. Each camera operates independently on different surface areas, allowing the system to maintain high productivity through the line camera while achieving high measurement precision through the matrix camera's 2D scanning capability.
Solution Approach 2:
The system transitions from single-dimensional line scanning to two-dimensional planar scanning by introducing the matrix camera. This dimensional enhancement allows simultaneous capture of multiple scan lines, improving both defect detection precision and coverage area without sacrificing the speed advantage of line scanning.
2Area of stationary object
If the cylindrical object rotates during inspection, then the scanning coverage is complete, but the synchronization complexity increases
Solution Approach 1:
The system performs preliminary positioning by detecting reference marks on the cylindrical object before inspection. This preliminary action establishes the rotational position and speed, allowing the cameras to synchronize their scanning with the object's rotation without requiring complex real-time coordination during the actual inspection process.
Solution Approach 2:
A sensor device continuously monitors the rotational position of the cylindrical object and provides feedback signals to the control unit. The control unit uses this feedback to adjust the scanning parameters of both cameras, ensuring they remain synchronized with the rotating object and achieve complete surface coverage.
3Measurement precision
If high-resolution scanning is performed, then the defect detection accuracy is high, but the inspection time increases
Solution Approach 1:
The inspection task is segmented between two cameras with different resolutions and scanning geometries. The line camera performs rapid preliminary scanning to identify areas of interest, while the matrix camera performs high-resolution inspection only on those specific areas, reducing total inspection time while maintaining high defect detection accuracy where needed.
Solution Approach 2:
Instead of applying high-resolution scanning uniformly across the entire surface, the system applies high-resolution scanning only partially to critical areas identified by the line camera. This partial action approach maintains high defect detection accuracy for important defects while minimizing the time penalty associated with high-resolution scanning.
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
Enables precise and quick assessment of surface processing quality, detects defects and errors, and compensates for printing issues in real-time, ensuring high-quality prints on cylindrical objects.
Implementation Method 1
a first camera (21) for scanning a first surface area (701) of a cylindrical object (6) with a first scanning section (30) having a first, line-like scanning geometry
Implementation Method 2
a second camera (22) for scanning a second surface area (702) of the same cylindrical object (6) with a second scanning section (31) having a second, planar scanning geometry
Data Source
Figure 1~5
Figure 2
Figure 6~10
AI summary
The invention relates to an inspection device for optical inspection of a surface of an at least substantially cylindrical object (6), comprising a first camera (21) for scanning a first surface area of a cylindrical object (6) with a first scanning section having a first, line-like scanning geometry (30) and a second camera (22) for scanning a second surface area (51) of the same cylindrical object (6) with a second scanning section having a second, planar scanning geometry (31), and a processing device (41) which is electrically connected to the first and second cameras (21, 22) and which is designed for processing scanning signals from the first and second cameras (21, 22).