Image Inspection Apparatus Pre-Printed Element Reduction
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Solution Overview
Problem
Current image inspection methods for overprinted pre-printed papers face significant errors due to the presence of pre-printed elements, which interfere with the detection of overprinted elements, especially when the pre-printed elements include patterns or backgrounds, leading to erroneous detections and incomplete inspections.
Innovation Solution
An image inspection apparatus and method that reduces the influence of pre-printed elements by preparing a new inspection object image using pre-printed element data, allowing for inspection of regions where overprinted elements exist without masking pre-printed elements, using techniques such as image subtraction or division to adjust brightness values and create an inspection object image for accurate comparison with overprinted element data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mask process is used to invalidate pre-printed elements in the captured image, then erroneous detections from pre-printed elements are reduced, but regions where overprinted elements overlap with pre-printed elements cannot be inspected
Solution Approach 1:
The patent segments the inspection process into two distinct phases: first capturing the pre-printed paper to create mask data, then capturing the overprinted paper and applying the mask to exclude only the pre-printed elements. This segmentation allows the system to separately identify and handle pre-printed regions, preventing them from causing erroneous detections while preserving the ability to inspect overprinted regions that do not overlap with pre-printed elements.
Solution Approach 2:
The patent performs preliminary capture of the pre-printed paper before overprinting to generate mask data in advance. This preliminary action creates a reference map of where pre-printed elements are located, which is then used during the inspection of the overprinted paper. By preparing the mask data beforehand, the system can efficiently exclude pre-printed regions during inspection without needing to re-capture or re-process the entire image.
2Reliability
If pre-printed element information is used as mask data to exclude pre-printed regions, then inspection errors from pre-printed elements are reduced, but all regions with pre-printed elements are excluded from inspection including regions with overprinted elements
Solution Approach 1:
The patent applies local quality by creating a spatial mask that selectively excludes only the specific regions containing pre-printed elements while leaving other regions unchanged and available for inspection. The mask data represents a spatial map where only the pre-printed regions are marked for exclusion, allowing the system to maintain full inspection coverage in non-overlapping areas while preventing erroneous detections in pre-printed areas.
3Loss of information
If the captured image includes both pre-printed and overprinted elements, then complete image data is obtained, but inspection accuracy deteriorates due to pre-printed elements causing erroneous detections
Solution Approach 1:
The patent introduces mask data as an intermediary element that mediates between the complete captured image (containing both pre-printed and overprinted elements) and the inspection process. The mask data acts as a filter that selectively removes the influence of pre-printed elements during comparison operations, allowing the system to maintain complete image data while preventing erroneous detections caused by pre-printed regions.
Data Source
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Figure 3(a)~3(e)
AI summary
An image inspection apparatus includes a pre-printed element reduction section that reduces influence of a pre-printed element on inspection and generates an inspection object image, and a comparative inspection section that compares the inspection object images with the additionally-recorded data, to inspect a performance level of a result of overprinting. Captured image data of the pre-printed paper image and the overprinted image is given to the pre-printed element reduction section. By using the captured image data of the pre-printed paper image, the pre-printed element reduction section reduces the pre-printed element included in the captured image data of the overprinted image and newly prepares the inspection object image.