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This paper reports the effect of printing and scanning on digital watermarks for a hard copy image and investigates the necessary conditions for the watermark to be robust against the printing and scanning process. The effect of the printing and scanning process on the image content is presented first, and that on the Discrete Cosine Transform (DCT) domain is discussed next. Thus, we have necessary conditions for the watermark to be robust and present a sufficient condition to construct robust watermarking. It is realized by decreasing mutual interference between the embedded elements. This will enable us to make image content common to both the electrical nets and the physical nets. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 11–19, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10059 [ABSTRACT FROM AUTHOR]

This paper proposes a digital signature scheme for a facsimile document which embeds a signature directly onto the document. The scheme modifies each run of white or black pixels with a single bit of the signature data. It is designed to be compatible with CCITT G3 facsimile standards and to protect the document from the insertion, modification, replacement, overwriting or deletion of characters. Furthermore, the total amount of data to be transmitted is about the same as that of the original facsimile document. In this paper, the authentication scheme is shown with a prototype model under a one-key encryption system. [ABSTRACT FROM AUTHOR]

This paper introduces a unified coding algorithm for dithered image and text data. When a gray scale image is represented by binary pseudo-half-tone, various binary patterns representing the same gray scale are generated based on the degree of freedom in the dither matrix. Then one of the binary patterns is selected to represent the corresponding text data. The proposed algorithm permits approximately 70k bytes of text data to be embedded into a 257 x 256-pixel image. It enables the transmission and handling of the mixture of image and text data without processing the two types of data separately. [ABSTRACT FROM AUTHOR]

This paper presents a data compression scheme which uses the statistical properties of ordered dither image by vector reputation. When a part of the dither image corresponding to n × n dithering matrix is described as a vector, it is observed that there is high correlation ratio between neighbor blocks for level information (the number of black pixels in the vector), the resolution information (the number of kinds of vectors) is a few, and their frequency distribution is very biased. Thus, if these two kinds of information on vector are coded separately by the variable length coding scheme, then high compression ratio can be attained for transmission and storage of dither image. [ABSTRACT FROM AUTHOR]

In the wake of the development of computer-aided facsimile equipment, office documents may be digitized, circulated on a network, and in the near future stored into files as soft copy. In this paper, we call this type of service facsimile-mail, and we discuss a multisignature method which is applied to facsimile documents. This method makes it possible to sign digital documents multiplexively and simplify the document exchange process. Document management is simplified and the reliability of the network is improved. [ABSTRACT FROM AUTHOR]

This paper proposes a new duplex modified-READ (KR) coding scheme for transmitting a facsimile picture on which other information can be embedded. When the vertical mode on the coding-scanning line is coded, the MR coding is carried out by moving the run-length of a black or white pel using the bit-series of an information source to be duplexed. This method offers a facsimile picture which has almost the same quality as its original without increasing the quantity of the MR-coding, and can transmit the second information without notice by a third person. For example, the second information with 2 k to 14 kbytes can be transmitted with one of the CCIfl test documents. This is an answer to conventional facsimile systems which have a lack of secrecy. This method also contributes to double the transmission rate so that transmission lines can be used more efficiently. [ABSTRACT FROM AUTHOR]

This study aims at emotional information processing and extracts the functions which generate several specified human facial expressions from a portrait. No satisfactory answer has been given to the problem as to how humans obtain information from facial expressions to identify another individual or to analyze an emotion. The major issue in studying the identification of an individual or the recognition of a facial expression is how and by what method the facial features should be described. This paper presents an approach to this problem by tracing the change of the facial expression on a planar portrait using the metamorphosis by a thin-plate spline and extracts the change quantitatively by the form of the facial function. Using the facial function, six kinds of facial images representing typical human emotions are generated from a portrait. The facial function will be used for the security check system. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(1): 36–46, 1997 [ABSTRACT FROM AUTHOR]