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511
The JPEG still picture compression standard
 Communications of the ACM
, 1991
"... This paper is a revised version of an article by the same title and author which appeared in the April 1991 issue of Communications of the ACM. For the past few years, a joint ISO/CCITT committee known as JPEG (Joint Photographic Experts Group) has been working to establish the first international c ..."
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This paper is a revised version of an article by the same title and author which appeared in the April 1991 issue of Communications of the ACM. For the past few years, a joint ISO/CCITT committee known as JPEG (Joint Photographic Experts Group) has been working to establish the first international compression standard for continuoustone still images, both grayscale and color. JPEG’s proposed standard aims to be generic, to support a wide variety of applications for continuoustone images. To meet the differing needs of many applications, the JPEG standard includes two basic compression methods, each with various modes of operation. A DCTbased method is specified for “lossy’ ’ compression, and a predictive method for “lossless’ ’ compression. JPEG features a simple lossy technique known as the Baseline method, a subset of the other DCTbased modes of operation. The Baseline method has been by far the most widely implemented JPEG method to date, and is sufficient in its own right for a large number of applications. This article provides an overview of the JPEG standard, and focuses in detail on the Baseline method. 1
The design and implementation of FFTW3
 PROCEEDINGS OF THE IEEE
, 2005
"... FFTW is an implementation of the discrete Fourier transform (DFT) that adapts to the hardware in order to maximize performance. This paper shows that such an approach can yield an implementation that is competitive with handoptimized libraries, and describes the software structure that makes our cu ..."
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Cited by 726 (3 self)
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FFTW is an implementation of the discrete Fourier transform (DFT) that adapts to the hardware in order to maximize performance. This paper shows that such an approach can yield an implementation that is competitive with handoptimized libraries, and describes the software structure that makes our current FFTW3 version flexible and adaptive. We further discuss a new algorithm for realdata DFTs of prime size, a new way of implementing DFTs by means of machinespecific singleinstruction, multipledata (SIMD) instructions, and how a specialpurpose compiler can derive optimized implementations of the discrete cosine and sine transforms automatically from a DFT algorithm.
Uncertainty principles and ideal atomic decomposition
 IEEE Transactions on Information Theory
, 2001
"... Suppose a discretetime signal S(t), 0 t<N, is a superposition of atoms taken from a combined time/frequency dictionary made of spike sequences 1ft = g and sinusoids expf2 iwt=N) = p N. Can one recover, from knowledge of S alone, the precise collection of atoms going to make up S? Because every d ..."
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Cited by 583 (20 self)
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Suppose a discretetime signal S(t), 0 t<N, is a superposition of atoms taken from a combined time/frequency dictionary made of spike sequences 1ft = g and sinusoids expf2 iwt=N) = p N. Can one recover, from knowledge of S alone, the precise collection of atoms going to make up S? Because every discretetime signal can be represented as a superposition of spikes alone, or as a superposition of sinusoids alone, there is no unique way of writing S as a sum of spikes and sinusoids in general. We prove that if S is representable as a highly sparse superposition of atoms from this time/frequency dictionary, then there is only one such highly sparse representation of S, and it can be obtained by solving the convex optimization problem of minimizing the `1 norm of the coe cients among all decompositions. Here \highly sparse " means that Nt + Nw < p N=2 where Nt is the number of time atoms, Nw is the number of frequency atoms, and N is the length of the discretetime signal.
Videoconferencing on the Internet
 IEEE/ACM Trans. on Networking
, 1996
"... This paper describes the INRIA Videoconferencing System (IVS), a low bandwidth tool for realtime video between workstations on the Internet using UDP datagrams and the IP multicast extension. The video coderdecoder (codec) is a software implementation of the UITT recommendation H.261 originally d ..."
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Cited by 337 (2 self)
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This paper describes the INRIA Videoconferencing System (IVS), a low bandwidth tool for realtime video between workstations on the Internet using UDP datagrams and the IP multicast extension. The video coderdecoder (codec) is a software implementation of the UITT recommendation H.261 originally developed for the Integrated Services Digital Network (ISDN). Our focus in this paper is on adapting this codec for the Internet environment. We propose a packetization scheme, an error control scheme and an output rate control scheme that adapts the image coding process based on network conditions. This work shows that it is possible to maintain videoconferences with reasonable quality across packetswitched networks without requiring special support from the network such as resource reservation or admission control.
Random projection in dimensionality reduction: applications to image and text data,”
 in Proceedings of the 7th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD ’01),
, 2001
"... ABSTRACT Random projections have recently emerged as a powerful method for dimensionality reduction. Theoretical results indicate that the method preserves distances quite nicely; however, empirical results are sparse. We present experimental results on using random projection as a dimensionality r ..."
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Cited by 245 (0 self)
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ABSTRACT Random projections have recently emerged as a powerful method for dimensionality reduction. Theoretical results indicate that the method preserves distances quite nicely; however, empirical results are sparse. We present experimental results on using random projection as a dimensionality reduction tool in a number of cases, where the high dimensionality of the data would otherwise lead to burdensome computations. Our application areas are the processing of both noisy and noiseless images, and information retrieval in text documents. We show that projecting the data onto a random lowerdimensional subspace yields results comparable to conventional dimensionality reduction methods such as principal component analysis: the similarity of data vectors is preserved well under random projection. However, using random projections is computationally significantly less expensive than using, e.g., principal component analysis. We also show experimentally that using a sparse random matrix gives additional computational savings in random projection.
An Application Level Video Gateway
, 1995
"... The current model for multicast transmission of video over the Internet assumes that a fixed average bandwidth is uniformly present throughout the network. Consequently, sources limit their transmission rates to accommodate the lowest bandwidth links, even though highbandwidth connectivity might be ..."
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Cited by 175 (4 self)
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The current model for multicast transmission of video over the Internet assumes that a fixed average bandwidth is uniformly present throughout the network. Consequently, sources limit their transmission rates to accommodate the lowest bandwidth links, even though highbandwidth connectivity might be available to many of the participants. We propose an architecture where a video transmission can be decomposed into multiple sessions with different bandwidth requirements using an applicationlevel gateway. Our video gateway transparently connects pairs of sessions into a single logical conference by manipulating the data and control information of the video streams. In particular, the gateway performs bandwidth adaptation through transcoding and ratecontrol. We describe an efficient algorithm for transcoding MotionJPEG to H.261 that runs in realtime on standard workstations. By making the Realtime Transport Protocol (RTP) an integral component of our architecture, the video gateway in...
Towards Robust and Hidden Image Copyright Labeling
, 1995
"... This paper first presents a "hidden label" approach for identifying the ownership and distribution of multimedia information (image or video data) in digital networked environment. Then it discusses criteria and difficulties in implementing the approach. Finally a method using a JPEG model ..."
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Cited by 145 (1 self)
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This paper first presents a "hidden label" approach for identifying the ownership and distribution of multimedia information (image or video data) in digital networked environment. Then it discusses criteria and difficulties in implementing the approach. Finally a method using a JPEG model based, frequency hopped, randomly sequenced pulse position modulated code (RSPPMC) is described. This method supports robustness of embedded labels against several damaging possibilities such as lossy data compression, low pass filtering and/or color space conversion. 1 Introduction The electronic representation and transfer of digitized multimedia information (text, video, and audio) have increased the potential for misuse and theft of such information, and significantly increases the problems associated with enforcing copyrights on multimedia information [1,2]. These problems are rooted from the intrinsic features of the digitally formated information: (1) making copies is easy and inexpensive; (...
Embedding Robust Labels into Images for Copyright Protection
 Proc. Int. Congr. Intellectural Property Rights for Specicalized Information, Knowledge and New Technologies
, 1995
"... This paper describes a set of novel steganographic methods to secretly embed robust labels into image data for identifying image copyright holder and original distributor in digital networked environment. The embedded label is undetectable, unremovable and unalterable. Furthermore it can survive pro ..."
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Cited by 112 (5 self)
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This paper describes a set of novel steganographic methods to secretly embed robust labels into image data for identifying image copyright holder and original distributor in digital networked environment. The embedded label is undetectable, unremovable and unalterable. Furthermore it can survive processing which does not seriously reduce the quality of the image, such as lossy image compression, low pass filtering and image format conversions. 1
H.263+: Video coding at low bit rates
 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY
, 1998
"... In this tutorial paper, we discuss the ITUT H.263+ (or H.263 Version 2) lowbitrate video coding standard. We first describe, briefly, the H.263 standard including its optional modes. We then address the 12 new negotiable modes of H.263+. Next, we present experimental results for these modes, bas ..."
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Cited by 111 (4 self)
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In this tutorial paper, we discuss the ITUT H.263+ (or H.263 Version 2) lowbitrate video coding standard. We first describe, briefly, the H.263 standard including its optional modes. We then address the 12 new negotiable modes of H.263+. Next, we present experimental results for these modes, based on our publicdomain implementation (see our Web site at
A Fast Algorithm for Deblurring Models with Neumann Boundary Conditions
, 1999
"... Blur removal is an important problem in signal and image processing. The blurring matrices obtained by using the zero boundary condition (corresponding to assuming dark background outside the scene) are Toeplitz matrices for 1dimensional problems and blockToeplitz Toeplitzblock matrices for 2dim ..."
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Cited by 107 (25 self)
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Blur removal is an important problem in signal and image processing. The blurring matrices obtained by using the zero boundary condition (corresponding to assuming dark background outside the scene) are Toeplitz matrices for 1dimensional problems and blockToeplitz Toeplitzblock matrices for 2dimensional cases. They are computationally intensive to invert especially in the block case. If the periodic boundary condition is used, the matrices become (block) circulant and can be diagonalized by discrete Fourier transform matrices. In this paper, we consider the use of the Neumann boundary condition (corresponding to a reflection of the original scene at the boundary). The resulting matrices are (block) Toeplitzplus Hankel matrices. We show that for symmetric blurring functions, these blurring matrices can always be diagonalized by discrete cosine transform matrices. Thus the cost of inversion is significantly lower than that of using the zero or periodic boundary conditions. We also s...