The Experts below are selected from a list of 54648 Experts worldwide ranked by ideXlab platform
Jiwhan Noh - One of the best experts on this subject based on the ideXlab platform.
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Fast and direct engraving of iridescent lettering on original product surface using laser interference to prevent counterfeiting
Optics and Lasers in Engineering, 2018Co-Authors: Sanghoon Ahn, Han-sung Bae, Hee Shin Kang, Jeng-o Kim, Jiwhan NohAbstract:Abstract We propose the engraving of a unique interference pattern on metal with the use of high-energy 1064 nm laser pulses fired through a Fresnel biprism (FB). The grating is patterned with 500 patterns for 5 ns, and the spacing of patterns can be adjusted according to the physical value of FB. By rotating the FB, the interference pattern is machined into metal to produce an encrypted iridescent character. Encrypted letters are engraved via assigning a Serial Number and corporate logos to a product (on which the metal is affixed) according to the viewing angle of the interference fringe. The resulting iridescently colored letters or Numbers are visible according to their viewing direction. By superimposing letters and Numbers, it is possible to store complex passwords, and forgery/counterfeiting can be easily detected by merely using the naked eye and an angle meter.
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Serial Number coding and decoding by laser interference direct patterning on the original product surface for anti-counterfeiting
Optics Express, 2017Co-Authors: In-yong Park, Youngduk Kim, Han-sung Bae, Jason Yoo, Sanghoon Ahn, Hee Shin Kang, Jiwhan NohAbstract:Here, we investigate a method to distinguish the counterfeits by patterning multiple reflective type grating directly on the surface of the original product and analyze the Serial Number from its rotation angles of diffracted fringes. The micro-sized gratings were fabricated on the surface of the material at high speeds by illuminating the interference fringe generated by passing a high-energy pulse laser through the Fresnel biprism. In addition, analysis of the grating’s diffraction fringes was performed using a continuous wave laser.
Markus G Kuhn - One of the best experts on this subject based on the ideXlab platform.
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information hiding a survey
Proceedings of the IEEE, 1999Co-Authors: Fabien A P Petitcolas, Ross Anderson, Markus G KuhnAbstract:Information-hiding techniques have recently become important in a Number of application areas. Digital audio, video, and pictures are increasingly furnished with distinguishing but imperceptible marks, which may contain a hidden copyright notice or Serial Number or even help to prevent unauthorized copying directly. Military communications systems make increasing use of traffic security techniques which, rather than merely concealing the content of a message using encryption, seek to conceal its sender, its receiver, or its very existence. Similar techniques are used in some mobile phone systems and schemes proposed for digital elections. Criminals try to use whatever traffic security properties are provided intentionally or otherwise in the available communications systems, and police forces try to restrict their use. However, many of the techniques proposed in this young and rapidly evolving field can trace their history back to antiquity, and many of them are surprisingly easy to circumvent. In this article, we try to give an overview of the field, of what we know, what works, what does not, and what are the interesting topics for research.
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information hiding a survey identification and protection of multimedia information
Proceedings of the IEEE, 1999Co-Authors: Fabien A P Petitcolas, R J Anderson, Markus G KuhnAbstract:Information-hiding techniques have recently become important in a Number of application areas. Digital audio, video, and pictures are increasingly furnished with distinguishing but imperceptible marks, which may contain a hidden copyright notice or Serial Number or even help to prevent unauthorized copying directly. Military communications systems make increasing use of traffic security techniques which, rather than merely concealing the content of a message using encryption, seek to conceal its sender, its receiver, or its very existence. Similar techniques are used in some mobile phone systems and schemes proposed for digital elections. Criminals try to use whatever traffic security properties are provided intentionally or otherwise in the available communications systems, and police forces try to restrict their use. However, many of the techniques proposed in this young and rapidly evolving field can trace their history back to antiquity, and many of them are surprisingly easy to circumvent. In this article, we try to give an overview of the field, of what we know, what works, what does not, and what are the interesting topics for research.
Shermeen Sayeda - One of the best experts on this subject based on the ideXlab platform.
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origin and destination estimation in new york city with automated fare system data
Transportation Research Record, 2002Co-Authors: James J Barry, Robert Newhouser, Adam Rahbee, Shermeen SayedaAbstract:New York City Transit's automated fare collection system, known as MetroCard, is an entry-only system that records the Serial Number of the MetroCard and the time and location (subway turnstile or bus Number) of each use. A methodology that estimates station-to-station origin and destination (O-D) trip tables by using this MetroCard information is described. The key is to determine the sequence of trips made throughout a day on each MetroCard. This is accomplished by sorting the MetroCard information by Serial Number and time and then extracting, for each MetroCard, the sequence of the trips and the station used at the origin of each trip. A set of straightforward algorithms is applied to each set of MetroCard trips to infer a destination station for each origin station. The algorithms are based on two primary assumptions. First, a high percentage of riders return to the destination station of their previous trip to begin their next trip. Second, a high percentage of riders end their last trip of the day ...
Yu Xie - One of the best experts on this subject based on the ideXlab platform.
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Serial Number extracting and recognizing applied in paper currency sorting system based on rbf network
Computational Intelligence, 2010Co-Authors: Li Liu, Yu XieAbstract:In view of the increasing demand of recognition system for paper currency Number, to develop a type of Number recognition system based on CIS and DSP. The hardware is composed of CIS and DSP which control image acquisition and process. The software is composed of image acquisition, character correction and recognition. To recognize character with noise pollution rapidly and accurately, a novel approach for character feature extraction based on statistics and fuzzy membership is proposed, and applied in RBF neural network. The experiment shows that the recognition system runs stably and accurately, the collected image shows clearly. The system runs with highly exact rate on Number recognition.
Sanghoon Ahn - One of the best experts on this subject based on the ideXlab platform.
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Fast and direct engraving of iridescent lettering on original product surface using laser interference to prevent counterfeiting
Optics and Lasers in Engineering, 2018Co-Authors: Sanghoon Ahn, Han-sung Bae, Hee Shin Kang, Jeng-o Kim, Jiwhan NohAbstract:Abstract We propose the engraving of a unique interference pattern on metal with the use of high-energy 1064 nm laser pulses fired through a Fresnel biprism (FB). The grating is patterned with 500 patterns for 5 ns, and the spacing of patterns can be adjusted according to the physical value of FB. By rotating the FB, the interference pattern is machined into metal to produce an encrypted iridescent character. Encrypted letters are engraved via assigning a Serial Number and corporate logos to a product (on which the metal is affixed) according to the viewing angle of the interference fringe. The resulting iridescently colored letters or Numbers are visible according to their viewing direction. By superimposing letters and Numbers, it is possible to store complex passwords, and forgery/counterfeiting can be easily detected by merely using the naked eye and an angle meter.
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Serial Number coding and decoding by laser interference direct patterning on the original product surface for anti-counterfeiting
Optics Express, 2017Co-Authors: In-yong Park, Youngduk Kim, Han-sung Bae, Jason Yoo, Sanghoon Ahn, Hee Shin Kang, Jiwhan NohAbstract:Here, we investigate a method to distinguish the counterfeits by patterning multiple reflective type grating directly on the surface of the original product and analyze the Serial Number from its rotation angles of diffracted fringes. The micro-sized gratings were fabricated on the surface of the material at high speeds by illuminating the interference fringe generated by passing a high-energy pulse laser through the Fresnel biprism. In addition, analysis of the grating’s diffraction fringes was performed using a continuous wave laser.
