This paper presents a document retrieval technique that is capable of searching document images without OCR (optical character recognition). The proposed technique retrieves document images by a new word shape coding scheme, which captures the document content through annotating each word image by a word shape code. In particular, we annotate word images by… (More)
This paper introduces a binarization method based on edge for video text images, especially for images with complex background or low contrast. The binarization method first detects the contour of the text, and utilizes a local thresholding method to decide the inner side of the contour, and then fills up the contour to form characters that are recognizable… (More)
A common problem encountered in signboard recognition is the perspective distortion of characters. In this paper, we propose a method which is able to directly recognize characters under severe perspective distortion without perspective rectification. In this method, a character is represented by a sequence of cross ratio spectra, in which the perspective… (More)
This paper reports a statistical script identification technique that determines the script of document images, especially camera-based images which suffer from perspective distortion. The identification technique represents a document image by a frequency vector of affine invariant signatures of characters, and identifies the script by comparing the vector… (More)
With large databases of document images available, a method for users to find keywords in documents will be useful. One approach is to perform Optical Character Recognition (OCR) on each document followed by indexing of the resulting text. However, if the quality of the document is poor or time is critical, complete OCR of all images is infeasible. This… (More)
A common problem encountered in recognizing real-scene symbols is the perspective deformation. In this paper, a recognition method resistant to perspective deformation is proposed, based on Cross-Ratio Spectrum descriptor. This method shows good resistance to severe perspective deformation and good discriminating power to similar symbols.
Document scripts and document orientations are important information for the document digitalization. Prior work has been reported to identify document scripts and document orientations, whereas most reported methods are very sensitive to document skew and low image resolution. This paper reports a document script and document orientation identification… (More)
Patent document images maintained by the U.S. patent database have a specific format, in which figures and text descriptions are separated into different sections. This makes it difficult for users to refer to a figure while reading the description or vice versa. The system introduced in this paper is to prepare these patent images for a friendly user… (More)