Structured Light Coating Inspection Device
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Solution Overview
Problem
The thin coating on documents such as identity cards and driving licenses is difficult to test or inspect due to its thin layer thickness, which poses a challenge in ensuring its integrity and quality during the manufacturing process.
Innovation Solution
A device that captures an image of a test structure on the document using an image sensor, determines image parameters, and compares them with reference parameters to efficiently check the coating's presence, thickness, and homogeneity without physical contact, utilizing infrared light, structured light, and optical filters to enhance image quality and filter out ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact inspection methods are used to test the coating, then physical measurement can be performed, but the inspection process becomes complex and time-consuming
Solution Approach 1:
The patent replaces mechanical contact inspection methods with optical imaging and image processing. The device uses an image sensor to capture images of the coating and applies image analysis algorithms to determine coating properties, eliminating the need for physical contact and complex mechanical measurement systems.
Solution Approach 2:
The patent introduces image processing algorithms as an intermediary between the image sensor and the coating evaluation. These algorithms analyze image parameters such as edge sharpness, contrast, and texture to indirectly measure coating thickness and quality, providing a simplified path from image capture to coating assessment.
2Length of moving object
If the coating layer thickness is reduced to achieve thin coating, then document protection is improved, but the coating becomes difficult to detect and measure
Solution Approach 1:
The patent changes the measurement parameters from direct physical measurement to optical image parameter analysis. By analyzing image parameters such as edge sharpness, contrast ratio, and texture patterns, the system can detect and measure ultra-thin coatings that would be invisible to conventional measurement tools.
Solution Approach 2:
The patent transitions from one-dimensional thickness measurement to multi-dimensional image parameter analysis. Instead of measuring only thickness, the system evaluates multiple image parameters including edge sharpness, contrast, texture, and color distribution, providing comprehensive coating characterization from a two-dimensional image.
3Ease of operation
If image processing is used to analyze coating properties, then non-contact inspection is achieved, but image quality requirements increase
Solution Approach 1:
The patent applies preliminary image processing steps such as noise filtering, contrast enhancement, and edge detection before final coating analysis. These preprocessing operations improve image quality and make the subsequent coating measurement more robust to variations in imaging conditions.
Solution Approach 2:
The system uses feedback from image parameter analysis to adjust imaging parameters and processing algorithms. By continuously evaluating image quality metrics and adjusting the inspection parameters accordingly, the system maintains accurate coating measurement across varying document types and coating conditions.
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 effective and non-contact inspection of document coatings, allowing for precise detection and measurement of coating thickness and homogeneity, thereby ensuring the quality and integrity of the documents during production.
Implementation Method 1
The lighting device can be designed to illuminate the test structure, i.e. to illuminate it in such a way that the test structure is illuminated. Here, light is sent through the test structure, which structures the light. However, the lighting device can illuminate the test structure in such a way that the structured light is obtained by reflecting the incident light on the test structure.
Implementation Method 2
The image of the test structure is captured using the image sensor.
Data Source
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AI summary
The invention relates to a device (100) for testing a coating (101) of a document (103), comprising: an image sensor (105); a lighting device (107) with a test structure (109), wherein the lighting device (107) is configured to illuminate the test structure (109) in order to emit structured light towards the document (103); a holder (113) arranged in the beam path (111) of the structured light, into which the document (103) can be inserted to reflect the structured light through the document (103) towards the image sensor (105) for image acquisition of the test structure (109); and a processor (115) configured to determine an image parameter of the image acquisition of the test structure (109) and to compare the image parameter with a reference parameter in order to test the coating (101) of the document (103).