Computer graphics
Isothetic polygon representation for contours
CVGIP: Image Understanding
An improved document skew angle estimation technique
Pattern Recognition Letters
A fast approach to the detection and correction of skew documents
Pattern Recognition Letters
The Document Spectrum for Page Layout Analysis
IEEE Transactions on Pattern Analysis and Machine Intelligence
Skew Detection via Principal Components Analysis
ICDAR '99 Proceedings of the Fifth International Conference on Document Analysis and Recognition
An Enhanced Skew Angle Estimation Technique for Binary Document Images
ICDAR '99 Proceedings of the Fifth International Conference on Document Analysis and Recognition
A novel boundary growing approach for accurate skew estimation of binary document images
Pattern Recognition Letters
Skew Detection in Binary Image Documents Based on Image Dilation and Region labeling Approach
ICPR '06 Proceedings of the 18th International Conference on Pattern Recognition - Volume 02
A fast skew detection and correction algorithm for machine printed words in Gurmukhi script
Proceedings of the International Workshop on Multilingual OCR
e-PCP: A robust skew detection method for scanned document images
Pattern Recognition
A novel Hough transform algorithm for multi-objective detection
IITA'09 Proceedings of the 3rd international conference on Intelligent information technology application
An adaptive technique for global and local skew correction in color documents
Expert Systems with Applications: An International Journal
Fast and robust skew estimation of scanned documents through background area information
Pattern Recognition Letters
Skew estimation of document images using bagging
IEEE Transactions on Image Processing
Document image analysis: issues, comparison of methods and remaining problems
Artificial Intelligence Review
A statistical global feature extraction method for optical font recognition
ACIIDS'11 Proceedings of the Third international conference on Intelligent information and database systems - Volume Part I
A template-based method for identifying input regions in survey forms
Pattern Recognition and Image Analysis
A novel statistical feature extraction method for textual images: Optical font recognition
Expert Systems with Applications: An International Journal
Transform invariant text extraction
The Visual Computer: International Journal of Computer Graphics
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The Hough transform provides a robust technique for skew detection in document images, but suffers from high time complexity which becomes prohibitive for detecting skew in large documents. Analysis of time complexity on various stages of skew detection process is carried out in this paper. A complete skew detection and correction process is divided into three parts: a preprocessing stage using a simplified form of block adjacency graph (BAG), voting process using the Hough transform and de-skewing the image using rotation. Skew correction phase, which is hitherto a neglected area, is analysed for the quality of de-skewed images with respect to the type of rotation. Fast algorithms for all the three stages are presented and exhaustive analysis on time complexity is conducted. It is shown that the overall time taken for the whole process is less than one second even for very large documents. It is also observed that time taken in rotation is as significant as in skew detection which is reduced with the help of fast algorithms using integer operations. While the BAG algorithm is found to be effective for documents with Roman script, it does not provide satisfactory results for Indian scripts where headline is a part of a script.