Ryu Ebisawa

Information Embedding Method for Home Printing of Certifications

In this paper, we describe our dot-pattern code, which can embed information onto the paper. Its main features are 1) no need to reserve a special room for the code, 2) obscure and unnoticeable, 3) comparatively large information capacity, 4) the absolute coordinates in the paper is measurable. We describe how to embed and detect the information onto / from the paper, and we estimate it by examination. From the examination, we found that our dot-pattern code is applicable to various kinds of papers, printers including ink-jet and scanners. We also found that even when the density of the black dot is greater than 6 %, over 8,000 bits could be safely embedded with error rate less than 10-6 . We also found that the embedded information could be detected correctly after the paper had been damaged.

Use of Gap-Filling Operation to Enhance Image Quality of Binary Image Watermarking

A method for enhancing the image quality of watermarked binary images containing text, drawings, graphs and tables is described. Using the proposed method, we can construct binary watermarking methods that do not perceptually degrade image quality and are robust against image deformation. The method can enhance image quality by accurately detecting the gaps created by the conventional watermarking method and by restoring them at little cost of watermark survivability. Testing of a prototype application demonstrated the validity of the method and revealed that it can widely be used in various binary image watermarking schemes.

Maintaining image quality when watermarking grayscale comic images for electronic books

Digital watermarking of comic images effectively protects the copyright of the content in electronic book applications. The characteristics of comic images were analyzed to determine the effect of digital watermarking on the line shapes. Modification of the shape edges by conventional watermarking methods can degrade image quality because the human eye is sensitive to the edges. The analysis revealed that slight changes in the black pixels in a comic image are barely perceived by the human eye when the image is displayed on a tablet PC. A method was then developed for embedding watermarks that minimizes modification of the white pixels compared to modification of the black ones. Experimental evaluation showed that this method improves the quality of watermarked grayscale comic images. Watermark robustness was almost the same as that with the conventional method in an assumed use case.

Third-party approach to controlling digital copiers

Information leakage through paper documents is not to be overlooked because it accounts for 43.8% of all the leakage in Japan. Most vendors of digital copiers are therefore offering new models equipped with additional security functions. Third-parties wanting to add security functions to copiers already used in their offices, however, need to know the copier specifications that the copier manufactures want to keep secret. In this paper we introduce our idea that enables a third party to control digital copiers. An application that enables us to monitor copying is also described.

Experiment on video watermark detection system using degraded original images

Watermarks often have to be detected from videos that have experienced such severe image processing as combinations of re-encoding and resizing in real applications. To improve watermark detection performance, this paper proposes a new method consisting of the following four steps: (a) estimate the image processing the watermarked images experienced, (b) apply the estimated image processing to the original images, (c) subtract the degraded original images from the watermarked images, and (d) detect watermarks from the difference images. Under the redistributing threat model, experimental evaluations show that the proposed method yields a detection ratio 34.4-percentage points higher than that yielded by the conventional method M1, which does not use original images.

Development of digital watermarking application technologies for newspapers

Newspapers, no different from other copyrighted works, are protected by the copyright laws. However, as the duplication itself is technically executable without any license agreement, in cases where users are ignorant of the copyright laws or have no intent to honor them, copies of newspapers end up to be illegally produced. In this paper, we report experiments for applying digital watermarking to newspapers. Digital watermarking is utilized to realize copyright management system that prevents illegal duplications while offering great convenience. Watermarking application is achieved in which the embedding artifacts are hardly noticeable and the embedded information extraction is stable.

Evaluation of Audio Watermark System Using Short Detection Time Frame

Assumed applications of copyright protection for music and synthesized voice are discussed. We developed a prototype audio watermark system combining the results of previous studies based on the patchwork algorithm, modifying the amplitude in the time-domain of voiced audio data, and using a reference signal. The results of experimental evaluation show that this our system can detect watermarks in a time frame as short as 2 s.

High-accuracy text search of hardcopy logs

Information leakage by way of paper documents has become such a serious matter that manufacturers of multifunction printers are providing a log capture device that captures document images whenever those printers are used. They are also offering a text search engine based on OCR text extraction from captured images. Since the accuracy rate of OCR is limited, this paper proposes a system increasing the accuracy of text searches in logs acquired in multifunction printers by numbering each page of paper documents and linking those ID numbers to the text data extracted from the original digital files. Experimental results show that this increases the accuracy rate of text searches from 52.4% to 98.0%.

Integrity verification method for video content using robust watermarking

A method is described for verifying video content integrity by checking the continuity of timecodes embedded as digital watermarks. Conventional verification methods using digital signatures and fragile watermarking are unable to distinguish between attacks and regular modifications and thus are unable to protect against threats to content. The proposed verification method distinguishes attacks against video content from regular modifications by detecting timecodes embedded in consecutive frames of the content and then checking their continuity. A prototype implementation showed that the method is more effective than conventional ones and that it can be used by a variety of applications using video content.

Evaluation of Integrity Verification System for Video Content Using Digital Watermarking

The effectiveness of a previously proposed system for verifying video content integrity was investigated using a prototype system. Unlike conventional verification systems using digital signatures and fragile watermarking, the proposed verification system embeds timecodes in consecutive frames of the content, extracts them some time later, and checks their continuity to distinguish attacks from regular modifications. Testing demonstrated that the system maintained picture quality, that the watermarks were robust against regular modifications, and that attacks could be detected reliably and be distinguished from regular modifications. This integrity verification system is thus well suited for a variety of applications using video content.