Print Image Inspection Using Global and Local Distortion Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image inspection systems struggle to accurately detect and correct partial positional misalignments and distortions in print sheets due to varying toner density, which can lead to inconsistent image quality and mixing of abnormal sheets with normal ones.
Innovation Solution
An image inspection apparatus and method that includes a scanning unit to compare overall and partial images with reference images, aligning them based on misalignment and distortion, and determining normality by quantifying these deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only overall image comparison is performed, then the inspection process is simple, but partial positional misalignment and distortion cannot be detected
Solution Approach 1:
The patent divides the inspection process into two distinct stages: overall alignment inspection and local distortion inspection. The image processing is segmented into comparing the entire image first, then dividing the image into multiple regions for detailed distortion analysis. This segmentation allows the system to maintain simplicity in the overall workflow while achieving high precision in detecting partial misalignments and distortions.
2Measurement precision
If local distortion detection is added to overall image comparison, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the image into multiple local regions after performing overall alignment, and applies distortion detection specifically to each region. This regional segmentation enables precise detection of local distortions without requiring complex processing of the entire image at once, thus improving detection precision while managing system complexity.
Solution Approach 2:
The patent performs overall alignment as a preliminary action before conducting local distortion detection. By first aligning the entire image and correcting gross misalignments, the system prepares the image data in advance, making the subsequent local distortion detection more efficient and accurate without requiring overly complex processing algorithms.
3Manufacturing precision
If registration alignment adjustment is used, then overall misalignment is corrected, but partial misalignment due to toner density variation cannot be addressed
Solution Approach 1:
The patent applies segmentation by dividing the aligned image into multiple local regions and performing distortion detection independently on each region. This allows the system to adapt to local variations in toner density and paper deformation that affect different parts of the image differently, while maintaining the overall alignment achieved by registration adjustment.
Solution Approach 2:
The patent implements local quality by applying different inspection criteria and processing methods to different regions of the image. Specifically, it detects and measures distortion in each local region separately, allowing the system to adapt to local characteristics such as varying toner density and paper deformation patterns, rather than applying a uniform inspection approach across the entire image.
Data Source
AI summary
An image inspection apparatus includes a scanning unit that scans a sheet conveyed from an image forming unit. The apparatus compares a scanned overall image of the sheet with a reference image to detect misalignment in image formation. Based on the misalignment, it aligns the scanned image with the reference image to generate a first image. The first image is then compared with the reference image to detect local distortions in different parts of the image. Based on the detected distortions, the apparatus performs local alignment to generate a second image. It then calculates distortion amounts for each part and determines whether the image is normal based on these values. This enables determination of image normality based on both misalignment and distortion.