17585309
3D geometric and optical modeling of warped document images from scanners
When one scans a document page from a thick bound volume, the curvature of the page to be scanned results in two kinds of distortion in the scanned document images: i) shade along the 'spine' of the book; and ii) warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. We first build practical models namely a 3D geometric model and a 3D optical model for the practical scanning conditions to reconstruct the 3D shape of book surface. We next restore the scanned document image using this shape based on de-shading and de-warping models. Finally, we evaluate the restoration results by comparing the OCR (optical character recognition) performance on the original and restored document images. The experiments show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly.
2536406
Improving Pronoun Resolution Using Statistics-Based Semantic Compatibility Information
In this paper we focus on how to improve pronoun resolution using the statistics-based semantic compatibility information. We investigate two unexplored issues that influence the effectiveness of such information: statistics source and learning framework. Specifically, we for the first time propose to utilize the web and the twin-candidate model, in addition to the previous combination of the corpus and the single-candidate model, to compute and apply the semantic information. Our study shows that the semantic compatibility obtained from the web can be effectively incorporated in the twin-candidate learning model and significantly improve the resolution of neutral pronouns.
15710341
Motion deblurring for optical character recognition
This paper investigates the problem of blurring caused by motion during image capture of text documents. Motion blurring prevents proper optical character recognition of the document text contents. One area of such applications is to deblur name card images obtained from handheld cameras. In this paper, a complete motion deblurring procedure for document images has been proposed. The method handles both uniform linear motion blur and uniform acceleration motion blur. Experiments on synthetic and real-life blurred images prove the feasibility and reliability of this algorithm provided that the motion is not too irregular. The restoration procedure consumes only small amount of computation time.
38236882
Chart analysis and recognition in document images
Hidden Markov models are a probabilistic modeling tool for time series data. It has been successfully applied to many areas, such as speech recognition, hand-written character recognition, etc. In this paper, we present a novel statistical approach using ergodic hidden Markov models to recognize scientific charts. We also present a newly developed feature extraction method for chart images. Unlike traditional primitive-based diagram recognition method, our approach need not recognize the graphic primitives in charts thus bypassing the recognition error problem caused by the inaccurate primitive extraction that is also a major obstacle to the construction of a general chart recognition system.
14312797
Correcting document image warping based on regression of curved text lines
Image warping is a common problem when one scans or photocopies a document page from a thick bound volume, resulting in shading and curved text lines in the spine area of the bound volume. This will not only impair readability, but will also reduce the OCR accuracy. Further to our earlier attempt to correct such images, this paper proposes a simpler connected component analysis and regression technique. Compared to our earlier method, the present system is computationally less expensive and is resolution independent too. The implementation of the new system and improvement of OCR accuracy are presented in this paper.
16665932
Document Flattening through Grid Modeling and Regularization
For document images captured by a digital camera, perspective and geometric distortions make it hard to recognize the document content properly. In this paper, we propose an integrated document restoration technique, which is capable of removing perspective and geometric distortions, and producing a flattened and fronto-parallel text image that is friendly to the generic OCR systems. The proposed document restoration is accomplished through grid modeling, which divides camera images into multiple quadrilateral grids using vertical text directions and the x lines and base lines. The global distortions are then removed through grid regularization that transforms the quadrilateral grids together with the pixel contents to the regular square grids. Experimental results show the proposed method is fast and easy for implementation
15032270
Authenticated Broadcast Encryption Scheme
With the advancement of wireless networks and mobile access devices such as cell phones and PDAs, multimedia services could be offered through wireless broadcast networks to these mobile devices. Therefore, there is a need to securely deliver multimedia content/data to many users over an insecure channel. Broadcast encryption scheme could provide this solution. The first formal study of broadcast encryption scheme is by Fiat and Noar in 1993. Since then, many broadcast encryption schemes have been proposed to improve the efficiency which is measured by three parameters, that is, length of transmission messages, users' storage and computational overhead at a user device. Some broadcast encryption schemes require less users storage, but the length of transmission messages or computation overhead depends on the number of users. In this paper, we proposed an authenticated broadcast encryption scheme which has an additional property than current proposed broadcast encryption schemes, that is, all users can verify who the sender is. The proposed scheme is proved to be secure against chosen ciphertext attacks based on the decision l-bilinear Diffie-Hellman exponent assumption. Furthermore, the simulation results, transmission messages nearly independent of the number of users and reasonable user storage show that the proposed authenticated broadcast encryption scheme is efficient and suitable for mobile devices.
29726361
Key Substitution Attacks on Some Provably Secure Signature Schemes
11363576
Functional Principles of Registry-based Service Discovery
As service discovery protocols (SDP) are becoming increasingly important for ubiquitous computing, they must behave according to predefined principles. We present the functional principles of service discovery for robust, registry-based service discovery. A methodology to guarantee adherence to these principles is provided and illustrated by formal verification of the principles against FRODO, an SDP built for the home environment. We show that, to make behavioral guarantees, an SDP has to be robust against network disturbances, and cannot rely only on the network layer
42190700
Key Substitution Attacks on Provably Secure Short Signature Schemes
Recently, Boneh et al. proposed provably secure short signature schemes in the standard model and in the random oracle model respectively. In this letter, we propose strong-key substitution attacks on these signature schemes. In one of the attacks, we show that an adversary can generate a new public key satisfying all legitimate signatures created by the legitimate signer.
34324862
Signature Schemes Based on 3rd Order Shift Registers
In this paper, we propose two digital signature schemes based on a third order linear feedback shift register. One of them is a normal signature scheme for signing document and the other is with encryption for intended reciever. These two signature schemes are different from most of the signature schemes which are based on discrete logarithm problem, elliptic curves discrete logarithm problem, RSA or quadratic residues. The efficient computational algorithm for computing kth term of a sequence is also presented. The advantage of these two schemes is that the computation is carried out in the ground field and not in an extension field. We also show that the security of these two signature schemes is equivalent to that of Schnorr signature scheme and Signed-ElGamal encryption scheme respectively.