Show-through Detection Using Pixel Expansion for Misaligned Documents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image processing systems face challenges in accurately detecting show-through positions between front and back sides of documents due to misalignment and manufacturing errors in optical systems, leading to incorrect identification of image data.
Innovation Solution
An image processing apparatus and method that acquires and binarizes input images from both sides of a document, generates an expanded image by expanding valid pixels, and identifies show-through positions using the binarized and expanded images to correct for positional discrepancies and improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image data from front and back sides are directly compared without expansion, then processing speed is maintained, but detection accuracy of show-through positions deteriorates due to positional displacement
Solution Approach 1:
The patent applies preliminary action by expanding valid pixels from the front-side image before comparing with the back-side image. This expansion process creates a buffer zone that anticipates and compensates for potential positional displacements, allowing the system to accurately identify show-through positions even when the images are not perfectly aligned. The expansion is performed in advance, so when the actual comparison occurs, the positional variations are already accounted for.
2Adaptability or versatility
If image sensors are positioned to read both sides of a document, then document processing capability is improved, but positional alignment between front and back images deteriorates due to manufacturing errors
Solution Approach 1:
The patent applies parameter changes by modifying the spatial distribution of valid pixels through the expansion process. Instead of attempting to physically realign the images or adjust sensor positions, the system changes the parameter of pixel coverage by expanding each valid pixel to cover a larger area. This parameter change compensates for the misalignment caused by manufacturing errors in the optical reading system, allowing accurate show-through detection despite the fixed sensor positions.
3Productivity
If binarization is applied to both images before comparison, then processing efficiency is improved, but detection reliability deteriorates when positional displacement occurs
Solution Approach 1:
The patent maintains processing efficiency while improving reliability by performing the pixel expansion operation on the binarized images before comparison. The preliminary binarization step converts the images to binary format for efficient processing, and then the expansion step creates the necessary buffer zones. This sequence of preliminary actions ensures that the system benefits from both the efficiency of binarization and the reliability of expansion-based displacement compensation.
Data Source
AI summary
An image processing apparatus includes an input image acquiring module for acquiring a first input image generated by reading one side of a document and a second input image generated by reading the other side of the document, a binarized image generator for generating a first binarized image by binarizing the first input image and a second binarized image by binarizing the second input image, an expanded image generator for generating an expanded image containing an expanded pixel obtained by expanding a valid pixel contained in the first binarized image, and a show-through position identifying module for identifying a show-through position in the second input image, based on the second binarized image and the expanded image.