Edward Delp | Purdue University (original) (raw)

Papers by Edward Delp

2004 International Conference on Image Processing, 2004. ICIP '04.

In this paper. an analysis of the efficiency o f three signal-to-noise ratio (SNR) scalablc strat... more In this paper. an analysis of the efficiency o f three signal-to-noise ratio (SNR) scalablc strategies for motion compensated video coders and their non-scalable counterpan is presented. After assuming some models and hypotheses with respect to the signals and systems involved, we have obtained the SNR of each coding strategy as a function of the decoding rate. To validate our analysis, we have compared our theoretical results with data from encodings of real video sequences. Results show that our analysis describes qualitatively the pcrformance o f each scalable stratcgy. and therefore. i t can be useful to understand main fratures of each scalable technique and what factors inHucnce their cfficiency.

Proceedings 1998 International Conference on Image Processing. ICIP98 (Cat. No.98CB36269)

The growth of networked multimedia systems has complicated copyright enforcement relative to digi... more The growth of networked multimedia systems has complicated copyright enforcement relative to digital images. One way to protect the copyright of digital images is to add an invisible structure to the image (known as a digital watermark) to identify the owner. In particular, it is important for Internet and image database applications that as much of the watermark as possible remain in the image after compression. Image adaptive watermarks are particularly resistant to removal by signal processing attacks such as filtering or compression. Common image adaptive watermarks operate in the transform domain (DCT or wavelet); the same domains are also used for popular image compression techniques (JPEG, EZW). This paper investigates whether matching the watermarking domain to the compression transform domain will make the watermark more robust to compression.

Proceedings 2001 International Conference on Image Processing (Cat. No.01CH37205)

Very Low Bitrate Video Coding, 1999

The characteristics of "non natural" images, such as predictive error frames used in vi... more The characteristics of "non natural" images, such as predictive error frames used in video compression, pre- sent a challenge for traditional compression techniques. Particularly difficult are small images, such as QCIF, where compression artifacts at low data rates are more noticeable. In this paper, we investigate techniques to improve the performance of a wavelet-based, rate scal- able video codec at

Proceedings 2000 International Conference on Image Processing (Cat. No.00CH37101)

In this paper, we develop a framework for efficiently encoding predictive error frames (PEF) as p... more In this paper, we develop a framework for efficiently encoding predictive error frames (PEF) as part of a rate scalable, wavelet-based video compression algorithm. We investigate the use of rate-distortion analysis to determine the significance of coefficients in the wavelet decomposition. Based on this analysis, we allocate the bit budget assigned to a PEF to the coefficients that yield the largest reduction in distortion, while maintaining the embedded and rate scalable properties of our video compression algorithm.

Proceedings 1999 International Conference on Image Processing (Cat. 99CH36348)

Rate scalable video compression is appealing for low bit rate applications, such as video telepho... more Rate scalable video compression is appealing for low bit rate applications, such as video telephony and wireless communication, where bandwidth available to an application cannot be guaranteed. In this paper, we investigate a set of strategies to increase the performance of SAMCo W , a rate scalable encoder [l, 21. These techniques are based on based on wavelet decomposition, spatial orientation trees, and motion compensation.

42nd Midwest Symposium on Circuits and Systems (Cat. No.99CH36356)

In this talk we will describe embedded image and video compression techniques. We describe an emb... more In this talk we will describe embedded image and video compression techniques. We describe an embedded zero tree-like approach that exploits the interdependency between color components that is known as Color Embedded Zero Tree Wavelet (CEZW). We will also present a video compression technique, Scalable Adaptive Motion Compensated Wavelet (SAMCoW) compression, that uses the CEZW data structure described above. We show that in addition to providing a wide range of rate scalability, SAMCoW achieves comparable performance to the more traditional hybrid video coders.

Protection of intellectual property is a critical issue in digital multimedia distribution system... more Protection of intellectual property is a critical issue in digital multimedia distribution systems. Cryptographic tools are commonly used for secure delivery of content and access keys to consumers via terrestrial, satellite, cable and Internet transmissions. A third requirement is the distribution of the copyright or usage rights associated with the digital content The integrity, as opposed to security, of this data is essential to prevent unauthorized modification. Two approaches have been proposed in the open literature: allocating special fields in the transport meam and embedding a watermark into multimedia content. We present two new methods, based on secret sharing, to create channels with guaranteed data integrity.

Despite the increase in email and other forms of digital communication, the use of printed docume... more Despite the increase in email and other forms of digital communication, the use of printed documents continues to increase every year. Many types of printed documents need to be "secure" or traceable to the printer that was used to print them. Examples of these include identity documents (e.g. passports) and documents used to commit a crime. Traditional protection methods such as special inks, security threads, or holograms, can be cost prohibitive. The goals of our work are to securely print and trace documents on low cost consumer printers such as inkjet and electrophotographic (laser) printers. We will accomplish this through the use of intrinsic and extrinsic features obtained from modelling the printing process. Specifically we show that the banding artifact in the EP print process can be viewed as an intrinsic feature of the printer used to identify both the model and make of the device. Methods for measuring and extracting the banding signals from documents are presented. The use of banding as an extrinsic feature is also explored.

Security, Steganography, and Watermarking of Multimedia Contents VII, 2005

Methodologies and tools for watermark evaluation and benchmarking facilitate the development of i... more Methodologies and tools for watermark evaluation and benchmarking facilitate the development of improved watermarking techniques. In this paper, we want to introduce and discuss the integration of audio watermark evaluation methods into the well-known web service Watermark Evaluation Testbed (WET) [1]. WET is enhanced by using. A special set of audio files with characterized content and a collection of single attacks as well as attack profiles [3] will help to select special audio files and attacks with their attack parameters. Motivation Digital watermarking has been proposed for a variety of applications, including content protection, authentication, and digital rights management. Many watermarking techniques have made claims regarding performance, such as invisibility, robustness, and capacity but currently it is not easy to objectively evaluate their performance claims. Watermark evaluation methodologies and tools allow an objective comparison of performance claims and facilitate the development of improved watermarking techniques. The performance of watermarking techniques may also be compared with the specific requirements of applications. It is clear that the development of digital watermarks is connected with their evaluation. The performance claimed by watermarking algorithms or their implementations should be verified using a fair and objective process. This process can be very complex and therefore the idea is to describe the evaluation process with special attacks and their specified or selected attack parameters or with a set of signal processing functions, which could be introduced to the content (for example, lossy compression). To improve the evaluation of digital watermarking algorithms the Watermark Evaluation Testbed (WET) system was developed at Purdue University [1][4] featuring a web-based user interface for the evaluation of still-image watermarks. In this paper, we will discuss and describe the procedure to integrate audio evaluation or benchmarking function into the existing WET service and the definition of complex attack scenarios, which are called profile attacks. The paper is structured as followed: Section 1 is a review of the existing WET benchmark for image watermarking. Section 2 is a review of the StirMark for audio and a description of audio benchmark profiles. The major portion of this section is a detailed description of the profiles, their parameters, and organization. Section 3 describes a proposed method for integrating the profiles into WET for Audio using an XML framework. Lastly, Section 4 has the conclusions and directions for future work.

Security, Steganography, and Watermarking of Multimedia Contents VII, 2005

While Digital Watermarking has received much attention in recent years, it is still a relatively ... more While Digital Watermarking has received much attention in recent years, it is still a relatively young technology. There are few accepted tools/metrics that can be used to evaluate the suitability of a watermarking technique for a specific application. This lack of a universally adopted set of metrics/methods has motivated us to develop a web-based digital watermark evaluation system called the Watermark Evaluation Testbed or WET. There have been more improvements over the first version of WET. We implemented batch mode with a queue that allows for user submitted jobs. In addition to StirMark 3.1 as an attack module, we added attack modules based on StirMark 4.0. For a new image fidelity measure, we evaluate conditional entropy as an image fidelity measure for different watermarking algorithms and different attacks. Also, we show the results of curve fitting the Receiver Operating Characteristic (ROC) analysis data using the Parzen window density estimation. The curve fits the data closely while having only two parameters to estimate.

Security, Steganography, and Watermarking of Multimedia Contents VI, 2004

Recently, we proposed a method for constructing a template for efficient temporal synchronization... more Recently, we proposed a method for constructing a template for efficient temporal synchronization in video watermarking. 1 Our temporal synchronization method uses a state machine key generator for producing the watermark embedded in successive frames of video. A feature extractor allows the watermark key schedule to be content dependent, increasing the difficulty of copy and ownership attacks. It was shown that efficient synchronization can be achieved by adding temporal redundancy into the key schedule. In this paper, we explore and extend the concepts of our temporal synchronization method to spatial synchronization. The key generator is used to construct the embedded watermark of non-overlapping blocks of the video, creating a tiled structure. 2-4 The autocorrelation of the tiled watermark contains local maxima or peaks with a grid-like structure, where the distance between the peaks indicates the scale of the watermark and the orientation of the peaks indicate the watermark rotation. Experimental results are obtained using digital image watermarks. Scaling and rotation attacks are investigated.

Security, Steganography, and Watermarking of Multimedia Contents VI, 2004

A robust, invisible watermarking scheme is proposed for digital images, where the watermark is em... more A robust, invisible watermarking scheme is proposed for digital images, where the watermark is embedded using the block-based Lapped Orthogonal Transform (LOT). The embedding process follows a spread spectrum watermarking approach. In contrast to the use of transforms such as DCT, our LOT watermarking scheme allows larger watermark embedding energy while maintaining the same level of subjective invisibility. In particular, the use of LOT reduces block artifacts caused by the insertion of the watermark in a block-by-block manner, hence obtaining a better balance between invisibility and robustness. Moreover, we use a human visual system (HVS) model to adaptively adjust the energy of the watermark during embedding. In our HVS model, each block is categorized into one of four classes (texture, fine-texture, edge,a n dplain-area) by using a feature known as the Texture Masking Energy (TME). Blocks with edges are also classified according to the edge direction. The block classification is used to adjust the watermark embedding parameters for each block.

SPIE Proceedings, 2004

While Digital Watermarking has received much attention within the academic community and private ... more While Digital Watermarking has received much attention within the academic community and private sector in recent years, it is still a relatively young technology. As such, there are few accepted tools and metrics that can be used to validate the performance claims asserted by members of the research community and evaluate the suitability of a watermarking technique for specific applications. This lack of a universally adopted set of metrics and methods has motivated us to develop a web-based digital watermark evaluation system known as the Watermark Evaluation Testbed or WET. This system has undergone several improvements since its inception. The ultimate goal of this work has been to develop a platform, where any watermarking researcher can test not only the performance of known techniques, but also their own techniques. This goal has been reached by the latest version of the system. New tools and concepts have been designed to achieve the desired objectives. This paper describes the new features of WET. Moreover, we also summarize the development process of the entire project as well as introduce new directions for future work.

SPIE Proceedings, 2000

Digital watermarking research has generally focused upon two classes of watermarks, fragile and r... more Digital watermarking research has generally focused upon two classes of watermarks, fragile and robust. Robust watermarks are designed to be detected even after attempts are made to remove them. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the watermarked content. Unfortunately, neither type of watermark is ideal when considering "information preserving" transformations (such as compression) which preserve the meaning or expression of the content and "information altering" transformations (such as feature replacement) which change the expression of the content. In this paper we describe a semi-fragile watermark for still images that can detect information altering transformations even after the watermarked content is subjected to information preserving alterations.

Visual Communications and Image Processing '99, 1998

Color embedded image compression is investigated by means of a set of core experiments that seek ... more Color embedded image compression is investigated by means of a set of core experiments that seek to evaluate the advantages of various color transformations, spatial orientation trees and the use of monochrome embedded coding schemes such as EZW and SPIHT. In order to take advantage of the interdependencies of the color components for a given color space, two new spatial orientation trees that relate frequency bands and color components are investigated.

Lecture Notes in Computer Science, 2000

In this paper, we study non-adaptive and adaptive steganographic techniques for images with low n... more In this paper, we study non-adaptive and adaptive steganographic techniques for images with low number of colors in palette image formats. We have introduced the concept of optimal parity assignment for the color palette and designed an efficient algorithm that finds the optimal parity assignment. The optimal parity is independent of the image histogram and depends only on the image palette. Thus, it can be used for increasing the security of steganographic techniques that embed message bits into the parity of palette colors. We have further developed two adaptive steganographic methods designed to avoid areas of uniform color and embed message bits into texturerich portions of the cover image. Both techniques were tested on computer generated images with large areas of uniform color and with fonts on uniform background. No obvious artifacts were introduced by either technique. The last, embedding-while-dithering, technique has been designed for palette images obtained from true color images using color quantization and dithering. In this technique, both the color quantization error and the error due to message embedding are diffused through the image to avoid introducing artifacts inconsistent with the dithering algorithm.

Signal Processing: Image Communication, 2001

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes... more A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, transmitted by cable operators, or made available as prepackaged media (e.g., a digital tape or a digital video disc). Before releasing their content for distribution, the content owners may require protection by specifying access conditions. Once the content is delivered to the consumer, it moves across home the network until it reaches its destination where it is stored or displayed. A copy protection system is needed to prevent unauthorized access to bit streams in transmission from one A/V device to another or while it is in storage on magnetic or optical media. Recently, two fundamental groups of technologies, encryption and watermarking, have been identified for protecting copyrighted digital multimedia content. This paper is an overview of the work done for protecting content owners' investment in intellectual property.

Signal Processing: Image Communication, 2003

With the advent of digital technologies, many new market opportunities have emerged for content o... more With the advent of digital technologies, many new market opportunities have emerged for content owners, content distributors, and consumer electronics/information technology industries. An essential requirement for developing a thriving marketplace is the protection of copyrighted content in digital form. There are four major stages in the delivery of content to the consumer: (1) capturing on digital media, (2) packaging, (3) distribution to home networks, and (4) transfer to the final audio/visual device within the home network. Entertainment content is of particular importance as it will be in high demand for many years to come. If an end-to-end security cannot be provided in a digital market, there would be no incentive for content creation. Lack of new supplies would result in detrimental effects for all the industries involved in the delivery chain. In this paper, we present the primary means of securing the entertainment content from creation to consumption in an attempt to understand the overall complexity of the problem.

Proceedings of the IEEE, 2005

The use of digital video offers immense opportunities for creators; however, the ability for anyo... more The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution ("piracy"), plagiarism, and misappropriation. Popular Internet software based on a peer-to-peer architecture has been used to share copyrighted movies, music, software, and other materials. Concerned about the consequences of illegal copying and distribution on a massive scale, content owners are interested in digital rights management (DRM) systems which can protect their rights and preserve the economic value of digital video. A DRM system protects and enforces the rights associated with the use of digital content. Unfortunately, the technical challenges for securing digital content are formidable and previous approaches have not succeeded. We overview the concepts and approaches for video DRM and describe methods for providing security, including the roles of encryption and video watermarking. Current efforts and issues are described in encryption, watermarking, and key management. Lastly, we identify challenges and directions for further investigation in video DRM.

2004 International Conference on Image Processing, 2004. ICIP '04.

In this paper. an analysis of the efficiency o f three signal-to-noise ratio (SNR) scalablc strat... more In this paper. an analysis of the efficiency o f three signal-to-noise ratio (SNR) scalablc strategies for motion compensated video coders and their non-scalable counterpan is presented. After assuming some models and hypotheses with respect to the signals and systems involved, we have obtained the SNR of each coding strategy as a function of the decoding rate. To validate our analysis, we have compared our theoretical results with data from encodings of real video sequences. Results show that our analysis describes qualitatively the pcrformance o f each scalable stratcgy. and therefore. i t can be useful to understand main fratures of each scalable technique and what factors inHucnce their cfficiency.

Proceedings 1998 International Conference on Image Processing. ICIP98 (Cat. No.98CB36269)

The growth of networked multimedia systems has complicated copyright enforcement relative to digi... more The growth of networked multimedia systems has complicated copyright enforcement relative to digital images. One way to protect the copyright of digital images is to add an invisible structure to the image (known as a digital watermark) to identify the owner. In particular, it is important for Internet and image database applications that as much of the watermark as possible remain in the image after compression. Image adaptive watermarks are particularly resistant to removal by signal processing attacks such as filtering or compression. Common image adaptive watermarks operate in the transform domain (DCT or wavelet); the same domains are also used for popular image compression techniques (JPEG, EZW). This paper investigates whether matching the watermarking domain to the compression transform domain will make the watermark more robust to compression.

Proceedings 2001 International Conference on Image Processing (Cat. No.01CH37205)

Very Low Bitrate Video Coding, 1999

The characteristics of "non natural" images, such as predictive error frames used in vi... more The characteristics of "non natural" images, such as predictive error frames used in video compression, pre- sent a challenge for traditional compression techniques. Particularly difficult are small images, such as QCIF, where compression artifacts at low data rates are more noticeable. In this paper, we investigate techniques to improve the performance of a wavelet-based, rate scal- able video codec at

Proceedings 2000 International Conference on Image Processing (Cat. No.00CH37101)

In this paper, we develop a framework for efficiently encoding predictive error frames (PEF) as p... more In this paper, we develop a framework for efficiently encoding predictive error frames (PEF) as part of a rate scalable, wavelet-based video compression algorithm. We investigate the use of rate-distortion analysis to determine the significance of coefficients in the wavelet decomposition. Based on this analysis, we allocate the bit budget assigned to a PEF to the coefficients that yield the largest reduction in distortion, while maintaining the embedded and rate scalable properties of our video compression algorithm.

Proceedings 1999 International Conference on Image Processing (Cat. 99CH36348)

Rate scalable video compression is appealing for low bit rate applications, such as video telepho... more Rate scalable video compression is appealing for low bit rate applications, such as video telephony and wireless communication, where bandwidth available to an application cannot be guaranteed. In this paper, we investigate a set of strategies to increase the performance of SAMCo W , a rate scalable encoder [l, 21. These techniques are based on based on wavelet decomposition, spatial orientation trees, and motion compensation.

42nd Midwest Symposium on Circuits and Systems (Cat. No.99CH36356)

In this talk we will describe embedded image and video compression techniques. We describe an emb... more In this talk we will describe embedded image and video compression techniques. We describe an embedded zero tree-like approach that exploits the interdependency between color components that is known as Color Embedded Zero Tree Wavelet (CEZW). We will also present a video compression technique, Scalable Adaptive Motion Compensated Wavelet (SAMCoW) compression, that uses the CEZW data structure described above. We show that in addition to providing a wide range of rate scalability, SAMCoW achieves comparable performance to the more traditional hybrid video coders.

Protection of intellectual property is a critical issue in digital multimedia distribution system... more Protection of intellectual property is a critical issue in digital multimedia distribution systems. Cryptographic tools are commonly used for secure delivery of content and access keys to consumers via terrestrial, satellite, cable and Internet transmissions. A third requirement is the distribution of the copyright or usage rights associated with the digital content The integrity, as opposed to security, of this data is essential to prevent unauthorized modification. Two approaches have been proposed in the open literature: allocating special fields in the transport meam and embedding a watermark into multimedia content. We present two new methods, based on secret sharing, to create channels with guaranteed data integrity.

Despite the increase in email and other forms of digital communication, the use of printed docume... more Despite the increase in email and other forms of digital communication, the use of printed documents continues to increase every year. Many types of printed documents need to be "secure" or traceable to the printer that was used to print them. Examples of these include identity documents (e.g. passports) and documents used to commit a crime. Traditional protection methods such as special inks, security threads, or holograms, can be cost prohibitive. The goals of our work are to securely print and trace documents on low cost consumer printers such as inkjet and electrophotographic (laser) printers. We will accomplish this through the use of intrinsic and extrinsic features obtained from modelling the printing process. Specifically we show that the banding artifact in the EP print process can be viewed as an intrinsic feature of the printer used to identify both the model and make of the device. Methods for measuring and extracting the banding signals from documents are presented. The use of banding as an extrinsic feature is also explored.

Security, Steganography, and Watermarking of Multimedia Contents VII, 2005

Methodologies and tools for watermark evaluation and benchmarking facilitate the development of i... more Methodologies and tools for watermark evaluation and benchmarking facilitate the development of improved watermarking techniques. In this paper, we want to introduce and discuss the integration of audio watermark evaluation methods into the well-known web service Watermark Evaluation Testbed (WET) [1]. WET is enhanced by using. A special set of audio files with characterized content and a collection of single attacks as well as attack profiles [3] will help to select special audio files and attacks with their attack parameters. Motivation Digital watermarking has been proposed for a variety of applications, including content protection, authentication, and digital rights management. Many watermarking techniques have made claims regarding performance, such as invisibility, robustness, and capacity but currently it is not easy to objectively evaluate their performance claims. Watermark evaluation methodologies and tools allow an objective comparison of performance claims and facilitate the development of improved watermarking techniques. The performance of watermarking techniques may also be compared with the specific requirements of applications. It is clear that the development of digital watermarks is connected with their evaluation. The performance claimed by watermarking algorithms or their implementations should be verified using a fair and objective process. This process can be very complex and therefore the idea is to describe the evaluation process with special attacks and their specified or selected attack parameters or with a set of signal processing functions, which could be introduced to the content (for example, lossy compression). To improve the evaluation of digital watermarking algorithms the Watermark Evaluation Testbed (WET) system was developed at Purdue University [1][4] featuring a web-based user interface for the evaluation of still-image watermarks. In this paper, we will discuss and describe the procedure to integrate audio evaluation or benchmarking function into the existing WET service and the definition of complex attack scenarios, which are called profile attacks. The paper is structured as followed: Section 1 is a review of the existing WET benchmark for image watermarking. Section 2 is a review of the StirMark for audio and a description of audio benchmark profiles. The major portion of this section is a detailed description of the profiles, their parameters, and organization. Section 3 describes a proposed method for integrating the profiles into WET for Audio using an XML framework. Lastly, Section 4 has the conclusions and directions for future work.

Security, Steganography, and Watermarking of Multimedia Contents VII, 2005

While Digital Watermarking has received much attention in recent years, it is still a relatively ... more While Digital Watermarking has received much attention in recent years, it is still a relatively young technology. There are few accepted tools/metrics that can be used to evaluate the suitability of a watermarking technique for a specific application. This lack of a universally adopted set of metrics/methods has motivated us to develop a web-based digital watermark evaluation system called the Watermark Evaluation Testbed or WET. There have been more improvements over the first version of WET. We implemented batch mode with a queue that allows for user submitted jobs. In addition to StirMark 3.1 as an attack module, we added attack modules based on StirMark 4.0. For a new image fidelity measure, we evaluate conditional entropy as an image fidelity measure for different watermarking algorithms and different attacks. Also, we show the results of curve fitting the Receiver Operating Characteristic (ROC) analysis data using the Parzen window density estimation. The curve fits the data closely while having only two parameters to estimate.

Security, Steganography, and Watermarking of Multimedia Contents VI, 2004

Recently, we proposed a method for constructing a template for efficient temporal synchronization... more Recently, we proposed a method for constructing a template for efficient temporal synchronization in video watermarking. 1 Our temporal synchronization method uses a state machine key generator for producing the watermark embedded in successive frames of video. A feature extractor allows the watermark key schedule to be content dependent, increasing the difficulty of copy and ownership attacks. It was shown that efficient synchronization can be achieved by adding temporal redundancy into the key schedule. In this paper, we explore and extend the concepts of our temporal synchronization method to spatial synchronization. The key generator is used to construct the embedded watermark of non-overlapping blocks of the video, creating a tiled structure. 2-4 The autocorrelation of the tiled watermark contains local maxima or peaks with a grid-like structure, where the distance between the peaks indicates the scale of the watermark and the orientation of the peaks indicate the watermark rotation. Experimental results are obtained using digital image watermarks. Scaling and rotation attacks are investigated.

Security, Steganography, and Watermarking of Multimedia Contents VI, 2004

A robust, invisible watermarking scheme is proposed for digital images, where the watermark is em... more A robust, invisible watermarking scheme is proposed for digital images, where the watermark is embedded using the block-based Lapped Orthogonal Transform (LOT). The embedding process follows a spread spectrum watermarking approach. In contrast to the use of transforms such as DCT, our LOT watermarking scheme allows larger watermark embedding energy while maintaining the same level of subjective invisibility. In particular, the use of LOT reduces block artifacts caused by the insertion of the watermark in a block-by-block manner, hence obtaining a better balance between invisibility and robustness. Moreover, we use a human visual system (HVS) model to adaptively adjust the energy of the watermark during embedding. In our HVS model, each block is categorized into one of four classes (texture, fine-texture, edge,a n dplain-area) by using a feature known as the Texture Masking Energy (TME). Blocks with edges are also classified according to the edge direction. The block classification is used to adjust the watermark embedding parameters for each block.

SPIE Proceedings, 2004

While Digital Watermarking has received much attention within the academic community and private ... more While Digital Watermarking has received much attention within the academic community and private sector in recent years, it is still a relatively young technology. As such, there are few accepted tools and metrics that can be used to validate the performance claims asserted by members of the research community and evaluate the suitability of a watermarking technique for specific applications. This lack of a universally adopted set of metrics and methods has motivated us to develop a web-based digital watermark evaluation system known as the Watermark Evaluation Testbed or WET. This system has undergone several improvements since its inception. The ultimate goal of this work has been to develop a platform, where any watermarking researcher can test not only the performance of known techniques, but also their own techniques. This goal has been reached by the latest version of the system. New tools and concepts have been designed to achieve the desired objectives. This paper describes the new features of WET. Moreover, we also summarize the development process of the entire project as well as introduce new directions for future work.

SPIE Proceedings, 2000

Digital watermarking research has generally focused upon two classes of watermarks, fragile and r... more Digital watermarking research has generally focused upon two classes of watermarks, fragile and robust. Robust watermarks are designed to be detected even after attempts are made to remove them. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the watermarked content. Unfortunately, neither type of watermark is ideal when considering "information preserving" transformations (such as compression) which preserve the meaning or expression of the content and "information altering" transformations (such as feature replacement) which change the expression of the content. In this paper we describe a semi-fragile watermark for still images that can detect information altering transformations even after the watermarked content is subjected to information preserving alterations.

Visual Communications and Image Processing '99, 1998

Color embedded image compression is investigated by means of a set of core experiments that seek ... more Color embedded image compression is investigated by means of a set of core experiments that seek to evaluate the advantages of various color transformations, spatial orientation trees and the use of monochrome embedded coding schemes such as EZW and SPIHT. In order to take advantage of the interdependencies of the color components for a given color space, two new spatial orientation trees that relate frequency bands and color components are investigated.

Lecture Notes in Computer Science, 2000

In this paper, we study non-adaptive and adaptive steganographic techniques for images with low n... more In this paper, we study non-adaptive and adaptive steganographic techniques for images with low number of colors in palette image formats. We have introduced the concept of optimal parity assignment for the color palette and designed an efficient algorithm that finds the optimal parity assignment. The optimal parity is independent of the image histogram and depends only on the image palette. Thus, it can be used for increasing the security of steganographic techniques that embed message bits into the parity of palette colors. We have further developed two adaptive steganographic methods designed to avoid areas of uniform color and embed message bits into texturerich portions of the cover image. Both techniques were tested on computer generated images with large areas of uniform color and with fonts on uniform background. No obvious artifacts were introduced by either technique. The last, embedding-while-dithering, technique has been designed for palette images obtained from true color images using color quantization and dithering. In this technique, both the color quantization error and the error due to message embedding are diffused through the image to avoid introducing artifacts inconsistent with the dithering algorithm.

Signal Processing: Image Communication, 2001

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes... more A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, transmitted by cable operators, or made available as prepackaged media (e.g., a digital tape or a digital video disc). Before releasing their content for distribution, the content owners may require protection by specifying access conditions. Once the content is delivered to the consumer, it moves across home the network until it reaches its destination where it is stored or displayed. A copy protection system is needed to prevent unauthorized access to bit streams in transmission from one A/V device to another or while it is in storage on magnetic or optical media. Recently, two fundamental groups of technologies, encryption and watermarking, have been identified for protecting copyrighted digital multimedia content. This paper is an overview of the work done for protecting content owners' investment in intellectual property.

Signal Processing: Image Communication, 2003

With the advent of digital technologies, many new market opportunities have emerged for content o... more With the advent of digital technologies, many new market opportunities have emerged for content owners, content distributors, and consumer electronics/information technology industries. An essential requirement for developing a thriving marketplace is the protection of copyrighted content in digital form. There are four major stages in the delivery of content to the consumer: (1) capturing on digital media, (2) packaging, (3) distribution to home networks, and (4) transfer to the final audio/visual device within the home network. Entertainment content is of particular importance as it will be in high demand for many years to come. If an end-to-end security cannot be provided in a digital market, there would be no incentive for content creation. Lack of new supplies would result in detrimental effects for all the industries involved in the delivery chain. In this paper, we present the primary means of securing the entertainment content from creation to consumption in an attempt to understand the overall complexity of the problem.

Proceedings of the IEEE, 2005

The use of digital video offers immense opportunities for creators; however, the ability for anyo... more The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution ("piracy"), plagiarism, and misappropriation. Popular Internet software based on a peer-to-peer architecture has been used to share copyrighted movies, music, software, and other materials. Concerned about the consequences of illegal copying and distribution on a massive scale, content owners are interested in digital rights management (DRM) systems which can protect their rights and preserve the economic value of digital video. A DRM system protects and enforces the rights associated with the use of digital content. Unfortunately, the technical challenges for securing digital content are formidable and previous approaches have not succeeded. We overview the concepts and approaches for video DRM and describe methods for providing security, including the roles of encryption and video watermarking. Current efforts and issues are described in encryption, watermarking, and key management. Lastly, we identify challenges and directions for further investigation in video DRM.