Corrugated Cardboard Edge Imaging for Warp Detection
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Solution Overview
Problem
Existing corrugated cardboard production systems face challenges in accurately and efficiently detecting deviations from flatness, or warp, in corrugated cardboard sheets, requiring high precision and additional identification steps.
Innovation Solution
A method and system using a camera positioned obliquely to capture images of overlapping sheets on a conveyor belt, analyzing the end-face edge for deviations from flatness, eliminating the need for height measurements and incorporating edge detection algorithms to identify and correct for twisting and rotation, with optional enclosure and lighting for enhanced visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If height measurement methods are used to detect warp, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical height measurement systems with a simplified optical camera-based system. Instead of using mechanical sensors to measure height at multiple points, the invention uses a camera to capture images of the end-face edge and analyzes the silhouette to detect warp, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent creates a visual copy (image) of the end-face edge using a camera, and then analyzes this copy to detect warp. This approach avoids direct physical measurement and allows for simplified processing of the copied visual information to determine flatness deviations.
2Measurement precision
If camera is positioned directly above test region, then measurement precision is improved, but ease of operation worsens due to difficulty in capturing edge profile
Solution Approach 1:
The patent changes the camera positioning from a top-down view (directly above the test region) to a side view (upstream and oblique to the test region). This dimensional change allows the camera to capture the end-face edge profile in a different orientation, making it easier to obtain clear edge images while still maintaining the ability to detect warp accurately.
3Productivity
If sheets are conveyed without overlapping, then productivity is improved, but measurement precision worsens due to inability to capture end-face edge
Solution Approach 1:
The patent arranges for sheets to overlap slightly before they reach the measurement zone, ensuring that the end-face edge is visible and accessible for imaging. This preliminary arrangement of sheets in an overlapping configuration enables the camera to capture the edge profile without requiring the sheets to be stationary or specially positioned during measurement, thus maintaining productivity while enabling accurate warp detection.
Data Source
AI summary
The invention relates to a corrugated cardboard production unit (2) and to a method for monitoring such a corrugated cardboard production unit (2), wherein the sheets (6) are placed so as to lie partially on top of one another on a conveyor belt (10) extending in a longitudinal direction (8), so that an end-face edge (26) of a leading sheet (6) rests on a trailing sheet (6). A defined region of a conveyor device (4) of the corrugated cardboard production unit (2) is specified as a test region (12), and images (I) of the test region (12) are captured by means of a camera (22). When viewed in the longitudinal direction (8), the camera (22) is oriented upstream and obliquely towards the test region (12) and thus towards the end-face edge (26) of a sheet (6) located in the test region (12). On the basis of at least one of the captured images (I), the course of the end-face edge (26) is analyzed with regard to a deviation from the flatness of the sheet (6) by means of an automatic image analysis.