Document Image Inclination Correction Using Circumscribed Rectangle Shape
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Solution Overview
Problem
Existing image reading apparatuses face challenges in accurately determining when to perform inclination correction of document images, leading to unreliable results due to differences in side inclinations and document handling variations.
Innovation Solution
The apparatus includes a determination unit that assesses the shape of the circumscribed rectangle of the document image to decide on inclination correction, using thresholds based on the document length-to-width ratio and inclination differences, ensuring accurate correction only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inclination correction is performed based on side inclination differences, then correction accuracy is improved, but false corrections are caused when documents are read in different orientations
Solution Approach 1:
The patent changes the determination parameter from side inclination angles to the shape characteristics of the circumscribed rectangle (aspect ratio). By using the ratio of the longer side length to the shorter side length of the circumscribed rectangle, the system can reliably distinguish between documents read in different orientations without performing false inclination corrections, thus resolving the contradiction between correction accuracy and reliability
Solution Approach 2:
The patent creates a standardized reference model of document orientation by reading a document in a predetermined orientation and storing its circumscribed rectangle shape characteristics. This reference copy is then used for comparison to determine if subsequent documents require inclination correction, eliminating the need for complex angle measurements and improving reliability
2Shape
If inclination correction is performed for all documents, then document alignment is improved, but processing time increases and unnecessary corrections occur
Solution Approach 1:
The patent applies partial action by performing inclination correction only for documents whose circumscribed rectangle shape characteristics differ from the reference model. By determining whether correction is necessary based on shape comparison before executing the correction, the system avoids unnecessary processing time while ensuring alignment is improved only when needed
Data Source
AI summary
A reading apparatus includes: a reading unit reading a document; a determination unit determining whether or not inclination correction of a document image is performed based on a shape of a circumscription image which is a circumscribed rectangle of the document image read from the document; and an output unit outputting an image according to a determination result.