Image Orientation Correction for Scanned Documents
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Solution Overview
Problem
Existing image processing systems face challenges in accurately determining the orientation of scanned documents, particularly travel documents like passports and ID cards, due to incorrect scanning directions and varied background designs, leading to errors in OCR processes.
Innovation Solution
An image processing apparatus that determines the document type and selects appropriate algorithms to correct the orientation of scanned images by searching for machine-readable zones or performing optical character recognition after rotating the image data by specific angles, ensuring accurate orientation determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single determination algorithm is used for all document types, then the device complexity is reduced, but the orientation determination accuracy deteriorates for specific document types like travel documents
Solution Approach 1:
The patent changes the parameter of determination algorithm selection based on document type. The system switches between a first determination algorithm (for travel documents with MRZ) and a second determination algorithm (for other documents), optimizing orientation accuracy for each document category without requiring a single complex algorithm to handle all cases
2Measurement precision
If the system rotates image data by multiple angles for orientation determination, then the orientation accuracy is improved, but the processing time increases
Solution Approach 1:
The patent performs preliminary document type determination before orientation determination. By first identifying whether the document is a travel document (using MRZ detection) or another type, the system can pre-select the appropriate determination algorithm, avoiding unnecessary multiple-angle rotations and reducing processing time while maintaining accuracy
3Measurement precision
If the system uses document type-specific determination algorithms, then the orientation determination accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments the orientation determination process into two distinct algorithms based on document type: a first determination algorithm for travel documents that utilizes MRZ (machine readable zone) characteristics, and a second determination algorithm for other document types. This segmentation allows each algorithm to be optimized for its specific document category, improving accuracy without requiring one overly complex universal algorithm
Data Source
AI summary
To provide an image processing apparatus capable of correcting an orientation of a scanned image, even if the orientation of a document during scanning is incorrect. An image processing apparatus includes a document type determination unit configured to determine a document type of image data obtained by optical reading, a selection unit configured to select, based on a determination result from the document type determination unit, a determination algorithm to be applied, from a plurality of determination algorithms for determining an orientation of an image, and an orientation determination unit configured to determine an orientation of an image in the image data by using the determination algorithm selected by the selection unit.