Showing papers on "Watermark published in 1994"

A digital watermark

Abstract: The paper discusses the feasibility of coding an "undetectable" digital water mark on a standard 512/spl times/512 intensity image with an 8 bit gray scale. The watermark is capable of carrying such information as authentication or authorisation codes, or a legend essential for image interpretation. This capability is envisaged to find application in image tagging, copyright enforcement, counterfeit protection, and controlled access. Two methods of implementation are discussed. The first is based on bit plane manipulation of the LSB, which offers easy and rapid decoding. The second method utilises linear addition of the water mark to the image data, and is more difficult to decode, offering inherent security. This linearity property also allows some image processing, such as averaging, to take place on the image, without corrupting the water mark beyond recovery. Either method is potentially compatible with JPEG and MPEG processing. >

Method and apparatus for reducing quantization artifacts in a hierarchical image storage and retrieval system

Abstract: The system and method reduces the quantization artifacts in the addition and removal of a digital watermark to and from a selected resolution image of a hierarchical image storage system where the watermark removal record is placed in a higher resolution image component. For those applications where preserving the image quality of a higher resolution image component is more critical than preserving the image quality of a lower resolution image component, the low-resolution image is modified according to the teachings of the present invention to minimize and in many cases eliminate the quantization artifacts at the higher resolution component.

Method and apparatus for protecting visual information with printed cryptographic watermarks

Abstract: A method and device for protecting visual information against unauthorized access and modification using a printed cryptographic watermark includes printing a first array of shapes on a first sheet of material to be protected and printing a second array of shapes on a second sheet of material, which is transparent so as to form a developer for developing a watermark encoded in a combination of the first and second arrays of shapes. The watermark is encoded by preparing each array using black and white pixels. Each pixel, which may be a square, rectangle, circle, hexagon or other shape, is split into first and second collections of subpixels, the first collection of subpixels appearing in the first array of shapes and the second collection of subpixels appearing in the second array of shapes. When the transparent second sheet of material is positioned directly on top of the first sheet of material with the second array of shapes aligned with the first array of shapes, the first sheet of material may be viewed through the transparent second sheet of material. In this manner, the encoded watermark, which was not visible in either one the two individually, becomes visible. Additionally, a first image may be encoded in the first sheet, a second image may be encoded in the second sheet, and the watermark may be viewed as a third image that is visible in the combination of the first and second sheets.

Watermarked paper and its production

Abstract: PURPOSE:To provide a watermarked paper and its production method capable of giving a false watermark of a desired picture, a symbol such as a logograph or a character, etc., to a paper by applying a simple treatment thereto. CONSTITUTION:There are provided a watermarked paper characteristically having a watermark 4 of a desired pattern formed by printing it on light- transmitting paper 1 such as Japanese paper using a transparent ink 2. The production method features printing a watermark 4 of a desired pattern on light-transmitting paper 1 such as Japanese paper using a transparent ink 2 according to intaglio printing method.

Copy impossible system for copying machine

Abstract: PURPOSE:To accomplish a copy impossible system by a copying machine for preventing securities such as a stock and a bond, etc., important documents such as a contract and a letter of attorney, etc., and confidential documents from being forged by use of a copying machine. CONSTITUTION:The pattern constituted of the design of a prescribed motif, or characters, etc., is printed on the suitable position of a sheet as a copying original 31 by treatment liquid, a watermark having enhanced light transmittivity is formed, and at the time of copying, the difference of the transmitted light quantity between the watermark part and the part other than the watermark part is read by an optical sensor 22 incorporated with the copying machine, and when the prescribed difference is detected, the function of the copying machine is stopped. Thus, the sheet as the copying original 31 is surely detected by the optical sensor 22, and also an inconspicuous watermark is formed, and the copying machine is set so that a copying operation may be stopped when the watermark is detected by the copying machine, then, copied sheets other than the necessary sheets cannot be obtained by forming the watermarks on necessary sheets such as the confidential documents and the important documents.

Justification judgement device for water-mark of securities

Abstract: PURPOSE:To provide a device for automatically judging the justification of a watermark inputted to securities CONSTITUTION:A bond 10 is irradiated with the light of a light source 32 The place of the watermark showing the identity of a watermark character group inputted to the bond being a reference is previously selected, and the presence or absence of passing light from the intersection point of lines which pass through the place of the selected watermark of the bond to be inspected and which are orthogonal to each other, is detected in a light-receiving unit 34 by shifting a mounting stand 28 by a motor 30 Then, a detection bit pattern is sent to CPU 22 CPU 22 reads the bit pattern of the bond being the reference which is previously stored in RAM 26 and judges whether it coincides with the detection bit pattern and displays that they coincide in a display 40

A digital watermark

Abstract: This paper discusses the feasibility of coding an "undetectable" digital water mark on a standard 512*512 intensity image with an 8 bit gray scale. The watermark is capable of carrying such information as authentication or authorisation codes, or a legend essential for image interpretation. This capability is envisaged to fmd application in image tagging, copyright enforcement, counterfeit protection, and controlled access. Two methods of implementation are discussed. The first is based on bit plane manipulation of the LSB, which offers easy and rapid decoding. The second method utilises linear addition of the water mark to the image data, and is more difficult to decode, offering inherent security. This linearity property also allows some image processing, such as averaging, to take place on the image, without corrupting the water mark beyond recovery. Either method is potentially compatible with JPEG and MPEG processing.

Water mark detection

Abstract: PURPOSE: To correctly detect a position of a watermark, and conduct high precision control by detecting the watermark on a paper web by a camera, by providing a means for detecting difference between a measured position of it and a reference position, and adjusting a pitch between watermarks. CONSTITUTION: A web 10 taken from a reel of paper having watermarks is fed to a sheeter 20 in a direction of an arrow A. A stack 22 of cut sheets respectively having watermarks is manufactured by the sheeter 20. The web 10 is guided along a freely running encoder roller 30, and output pulses are generated by an encoder 32 which rotates with the roller 30. A processing system 100 processes the output pulses from the encoder 32 and video information from a camera 40, and inputs periodic pulses to an input 24 of the sheeter 20. A pitch between the watermarks is thus adjusted based on difference between a measured position of the watermark and a reference position.