04-10-2012, 11:17 AM
Digital Watermarking
Digital Watermarking.doc (Size: 738.5 KB / Downloads: 47)
Introduction
The popularity of World Wide Web demonstrated the commercial potential of offering multimedia resources through the digital networks. Since commercial interests seek to use the digital network to offer digital media for profit, they have a strong interest in protecting their ownership rights. The digital data can be processed, accessed, and it can be transmitted very quickly using networks. There are numerous technical, legal, and organizational problems which arise when there is wide scale use of digital documents.
Digital information can be copied any number of times from one medium to another; they can be transmitted through networks, etc., all without compromising the quality of the data. There is no way to distinguish between an original electronic documents and its copy. It is easy to change any part of an un protected electronic document. One possibility here is to replace original signatures with cryptographic methods .Digital signature is data items formed by the signatory and created from the document that is to be signed.
It relates the documents to the signatory in a secure and reliable way. The signature of one document cannot be used to sign another, even if the two documents in question differ by just a single character. Digital watermarking has been proposed as one way to accomplish this.
Also advanced Internet services enabled the users to create copy and distribute multimedia products such as audio, video, and still images with much ease and less effort, minimum or no cost, and in less time.
Though it encouraged trading on the Internet, but on the other hand it has created the problem of illegal copying or copyright infringement. E-commerce has become a significant business with well-established online shopping services, and online delivery of digital media such as audio and video. Thus, protection of digit alrights assumed a primary importance in the digital age.
History of Watermarking
Although paper was invented in China over a thousand years ago, the Europeans only began to manufacture it in the 11th and 12th centuries, after Muslims had established the first paper mills in Spain. Soon after its invention, Chinese merchants and missionaries transmitted paper, and knowledge of papermaking, to neighboring lands such as Japan, Korea, and Central Asia. It was there that Muslims first encountered it in the 8th century. Islamic civilization spread knowledge of paper and papermaking to Iraq, Syria, Egypt, North Africa and
finally, Spain .Most accounts of the history of paper focus either on its Origins in China or its development in Europe, and simply disregard the centuries when knowledge of paper and papermaking spread throughout the Islamic lands. Some of this neglect is due to the difficulty of studying Islamic paper, since Islamic papers, unlike later European papers, do not have watermarks and are consequently very difficult to localize and date .This explains why the oldest watermarked paper found in archives dates back to 1292, in Fabriano, Italy. The marks were made by adding thin wire patterns to the paper molds. The paper would be slightly thinner where the wire was and hence more transparent. At the end of 13th century about 40 paper mills were sharing the paper market in Fabriano and producing paper with different format, quality and price. Competition was very high and it was difficult for any party to keep track of paper provenance and thus format and quality identification. The introduction of watermarks was the best method to eliminate any possibility of confusion. The digitization of today’s world has expanded the watermarking concept to include digital approaches for use in authenticating
ownership claims and protecting proprietary interests .
Overview of Digital Watermarking
Information hiding (or data hiding) is a general term encircling a wide range of problems beyond the embedding messages in content. The term hiding can refer to either for information imperceptibility (watermarking) or information secrecy (steganography). Watermarking and steganography are two important sub disciplines of information hiding that are closely related to each other and may be coincide but with different underlying properties, requirements and designs, thus result in different technical solutions .Steganography is a term derived from the Greek words steganos, which means “covered,” and graphia, which means “writing.” It is the art of concealed communication. The existence of a message is secret.
Examples include invisible ink which would glow over a flame used by both the British and Americans to communicate secretly during the American Revolution and hidden text using invisible ink to print small dots above or below letters and by changing the heights of letter-strokes in texts used by German spies in World Wars. Watermarking which a term used back from paper watermarking, on the other hand has the additional concept of resilience against attempts to remove the hidden data. This is because the information hidden by watermarking systems is
always associated to the digital object to be protected or its owner while stenographic systems just hide any information. Robustness criteria are also different since steganography mainly concerns with detection of hidden message while watermarking concerns potential removal by a pirate. Besides, steganography typically relates to covert point-to-point communication while watermarking is usually one-to-many
Definition of Digital Watermarking
Digital watermarking can be defined as the process of embedding embedding a certain piece of information (technically known as watermark) into multimedia content including text documents, images, audio or video streams, such that the watermark can be detected or extracted later to make an assertion about the data. A generalized watermark model consists of watermark encoding and detection processes as shown in Fig. 1 and Fig. 2 .The inputs to the embedding process are the watermark, the cover object and a secret key. The key is used to enforce security and to protect the watermark. The output of the watermarking scheme is the watermarked data. The channel for the watermarked data could be a lossy, noisy, unreliable channel. Thus the received data may be different from the original watermarked data. The inputs for extraction are the received watermarked data and the key corresponding to the embedding key. The output of the watermark recovery process is the recovered watermark
Digital Watermarking.doc (Size: 738.5 KB / Downloads: 47)
Introduction
The popularity of World Wide Web demonstrated the commercial potential of offering multimedia resources through the digital networks. Since commercial interests seek to use the digital network to offer digital media for profit, they have a strong interest in protecting their ownership rights. The digital data can be processed, accessed, and it can be transmitted very quickly using networks. There are numerous technical, legal, and organizational problems which arise when there is wide scale use of digital documents.
Digital information can be copied any number of times from one medium to another; they can be transmitted through networks, etc., all without compromising the quality of the data. There is no way to distinguish between an original electronic documents and its copy. It is easy to change any part of an un protected electronic document. One possibility here is to replace original signatures with cryptographic methods .Digital signature is data items formed by the signatory and created from the document that is to be signed.
It relates the documents to the signatory in a secure and reliable way. The signature of one document cannot be used to sign another, even if the two documents in question differ by just a single character. Digital watermarking has been proposed as one way to accomplish this.
Also advanced Internet services enabled the users to create copy and distribute multimedia products such as audio, video, and still images with much ease and less effort, minimum or no cost, and in less time.
Though it encouraged trading on the Internet, but on the other hand it has created the problem of illegal copying or copyright infringement. E-commerce has become a significant business with well-established online shopping services, and online delivery of digital media such as audio and video. Thus, protection of digit alrights assumed a primary importance in the digital age.
History of Watermarking
Although paper was invented in China over a thousand years ago, the Europeans only began to manufacture it in the 11th and 12th centuries, after Muslims had established the first paper mills in Spain. Soon after its invention, Chinese merchants and missionaries transmitted paper, and knowledge of papermaking, to neighboring lands such as Japan, Korea, and Central Asia. It was there that Muslims first encountered it in the 8th century. Islamic civilization spread knowledge of paper and papermaking to Iraq, Syria, Egypt, North Africa and
finally, Spain .Most accounts of the history of paper focus either on its Origins in China or its development in Europe, and simply disregard the centuries when knowledge of paper and papermaking spread throughout the Islamic lands. Some of this neglect is due to the difficulty of studying Islamic paper, since Islamic papers, unlike later European papers, do not have watermarks and are consequently very difficult to localize and date .This explains why the oldest watermarked paper found in archives dates back to 1292, in Fabriano, Italy. The marks were made by adding thin wire patterns to the paper molds. The paper would be slightly thinner where the wire was and hence more transparent. At the end of 13th century about 40 paper mills were sharing the paper market in Fabriano and producing paper with different format, quality and price. Competition was very high and it was difficult for any party to keep track of paper provenance and thus format and quality identification. The introduction of watermarks was the best method to eliminate any possibility of confusion. The digitization of today’s world has expanded the watermarking concept to include digital approaches for use in authenticating
ownership claims and protecting proprietary interests .
Overview of Digital Watermarking
Information hiding (or data hiding) is a general term encircling a wide range of problems beyond the embedding messages in content. The term hiding can refer to either for information imperceptibility (watermarking) or information secrecy (steganography). Watermarking and steganography are two important sub disciplines of information hiding that are closely related to each other and may be coincide but with different underlying properties, requirements and designs, thus result in different technical solutions .Steganography is a term derived from the Greek words steganos, which means “covered,” and graphia, which means “writing.” It is the art of concealed communication. The existence of a message is secret.
Examples include invisible ink which would glow over a flame used by both the British and Americans to communicate secretly during the American Revolution and hidden text using invisible ink to print small dots above or below letters and by changing the heights of letter-strokes in texts used by German spies in World Wars. Watermarking which a term used back from paper watermarking, on the other hand has the additional concept of resilience against attempts to remove the hidden data. This is because the information hidden by watermarking systems is
always associated to the digital object to be protected or its owner while stenographic systems just hide any information. Robustness criteria are also different since steganography mainly concerns with detection of hidden message while watermarking concerns potential removal by a pirate. Besides, steganography typically relates to covert point-to-point communication while watermarking is usually one-to-many
Definition of Digital Watermarking
Digital watermarking can be defined as the process of embedding embedding a certain piece of information (technically known as watermark) into multimedia content including text documents, images, audio or video streams, such that the watermark can be detected or extracted later to make an assertion about the data. A generalized watermark model consists of watermark encoding and detection processes as shown in Fig. 1 and Fig. 2 .The inputs to the embedding process are the watermark, the cover object and a secret key. The key is used to enforce security and to protect the watermark. The output of the watermarking scheme is the watermarked data. The channel for the watermarked data could be a lossy, noisy, unreliable channel. Thus the received data may be different from the original watermarked data. The inputs for extraction are the received watermarked data and the key corresponding to the embedding key. The output of the watermark recovery process is the recovered watermark