nils-herrmann/clean_scirepeval huggingface dataset:
Providing multimedia services to a diverse set of consumer devices

This paper describes an assortment of techniques and a system to adapt multimedia content. The ability to do so allows service providers to offer a wide range of multimedia services to users with various client capabilities. We present a system that is capable of serving a variety of client devices. To do so, we propose novel transcoding and video summarization algorithms. Additionally, we describe a system that invokes these algorithms dynamically as a function of the network, terminal and user information. The impact on the consumer is the added functionality that can be realized and the quality of their service.
Data hiding in hard-copy text documents robust to print, scan and photocopy operations

This paper describes a method for hiding data inside printed text documents that is resilient to print/scan and photocopying operations. Using the principle of channel coding with side information, the embedder inserts a message into a text document while treating the content of the document as known interference. The data is embedded by making small changes to text characters before the document is printed. Using a simple correlation-based detector in conjunction with an error correction code, the hidden data can be extracted from a photocopy of the printed document. By enhancing the detector with an optical character recognition algorithm, the embedded data can be extracted even after multiple rounds of photocopying. Results from subjective tests show that the changes made by the embedding algorithm, while perceptible, are not obtrusive to a lay reader.
Video querying via compact descriptors of visually salient objects

We consider the problem of extracting descriptors that represent visually salient portions of a video sequence. Most state-of-the-art schemes generate video descriptors by extracting features, e.g., SIFT or SURF or other keypoint-based features, from individual video frames. This approach is wasteful in scenarios that impose constraints on storage, communication overhead and on the allowable computational complexity for video querying. More importantly, the descriptors obtained by this approach generally do not provide semantic clues about the video content. In this paper, we investigate new feature-agnostic approaches for efficient retrieval of similar video content. We evaluate the efficiency and accuracy of retrieval when k-means clustering is applied to image features extracted from video frames. We also propose a new approach in which the extraction of compact video descriptors is cast as a Non-negative Matrix Factorization (NMF) problem. Initial experiments on video-based matching suggest that compact descriptors obtained via low-rank matrix factorization improve discriminability and robustness to parameter selection compared to k-means clustering.
A Multi-Standards HDTV Video Decoder for Blu-Ray Disc Standard

This paper presents an HDTV video decoder core that is is able to decode MPEG-2, MPEG-4 AVC and VC-1 formats and is fully compatible with the Blu-ray Disc standard. A novel re-configurable architecture is adopted to achieve reduced hardware, and a data compression method suitable for all video decoding standards is applied to reduce memory data usage and access bandwidth. The circuit volume of the core is 1.5 Mgates with 90 nm CMOS technology and operation clock frequency is 162 MHz for 1080 i at 30 fr/s.
Feature transformation of biometric templates for secure biometric systems based on error correcting codes

Secure storage of biometric templates is extremely important because a compromised biometric cannot be revoked and replaced an unlimited number of times. In many approaches proposed for secure biometric storage, an error correcting code (ECC) is applied to the enrollment biometric and the resulting parity or syndrome symbols are stored on the access control device, instead of the original biometric. The principal challenge here is that most standard ECCs are designed for memoryless channel statistics, whereas the variations between enrollment and probe biometrics have significant spatial correlation. To address this challenge, we propose to transform the original biometric into a feature vector that is explicitly matched to standard ECCs, thereby improving the security-robustness tradeoff of the overall biometric system. As a concrete example, we transform fingerprint minutiae maps into feature vectors compatible with ECCs designed for a binary symmetric channel. We conduct a statistical analysis of these feature vectors and show how our feature transformation algorithm may be combined with Low-Density Parity Check (LDPC) codes to obtain a secure fingerprint biometric system.
Joint rate control for coding multiple video objects

This paper describes an algorithm which achieves a constant bit rate when coding multiple video objects. This implementation is based on the current MPEG-4 video verification model. Each object maintains its own set of parameters. With these parameters an initial target estimate is made for each object. Based on the buffer fullness, the total target is adjusted and then distributed proportional to the size, motion, and variance of each object. Appropriate quantization parameters can be calculated for each video object based on the new individual targets and second order model parameters. This algorithm assures that the target bit rate is achieved for low latency video coding.
Resource adaptation based on MPEG-21 usage environment descriptions

This paper addresses several aspects related to the distribution of content. The first aim is to provide an overview of the Universal Multimedia Access (UMA) concept. The primary function of UMA services is to provide the best Quality of Service (QoS) or User experience by either selecting/adapting the content format to meet the playback environment, or adapting the content playback environment to accommodate the content. The second purpose of this paper is to describe how the concept of UMA relates to the emerging MPEG standard, Digital Item Adaptation (DIA), which will become Part 7 of the MPEG-21 standard. An update on the standards activity in this area is presented. Finally, the third purpose of this paper is to describe the impact that DIA will have on transcoding strategies, where we describe topics that we are currently working on and analyze some areas of future research.
Video background subtraction using semi-supervised robust matrix completion

We propose a factorized robust matrix completion (FRMC) algorithm with global motion compensation to solve the video background subtraction problem. The algorithm decomposes a sequence of video frames into the sum of a low rank background component and a sparse motion component. The algorithm alternates between the solution of each component following a Pareto curve trajectory for each subproblem. For videos with moving background, we utilize the motion vectors extracted from the coded video bitstream to compensate for the change in the camera perspective. Performance evaluations show that our approach is faster than state-of-the-art solvers and results in highly accurate motion segmentation.
HEVC-Compatible Extensions for Advanced Coding of 3D and Multiview Video

This article provides an overview of standardized extensions of HEVC for the advanced coding of 3D and multiview video. In those extensions, new coding tools that better exploit the inter-view redundancy of the multiview texture videos have been developed. Additionally, dedicated tools for the improved coding of depth have been extensively studied and incorporated into the standard. In this paper, the performance of these extensions is assessed, and experimental results demonstrate notable gains in coding efficiency.
Rate allocation for FGS coded video using composite R-D analysis

In this paper, we propose a constant quality rate allocation algorithm for MPEG-4 FGS (fine granularity scalability) coded video sequences. The rate allocation problem is formulated as a constrained minimization of quality fluctuation. The minimization is solved using a novel composite rate distortion analysis. For a set of video frames, a composite rate distortion curve is first computed and then used for computing the optimal rate allocation. The proposed algorithm is very efficient because it is neither iterative nor recursive. In addition, after the composite rate distortion curve is computed, it can be used to calculate optimal rate allocation for any rate budget. Therefore, it is suitable for FGS coded bitstreams, which need to be transmitted and decoded many times at many different rates. Moreover, the composite rate distortion curve can be updated efficiently over sliding windows. This further reduces the computational complexity. Experiments using both synthetic and real FGS coded videos have shown the effectiveness and the efficiency of the proposed algorithm.
Video browsing system based on compressed domain feature extraction

We present a video browsing system that dynamically extracts features and other content-description (meta-data) from compressed video. We devise a description scheme for a video browsing system that combines color and motion descriptors extracted in the compressed domain. The extraction is fast and enables our proposed dynamic feature extraction based video browsing system. We examine the tradeoff between fast feature extraction and accuracy of matching to arrive at a combination of color and motion descriptors that is easy to extract and provides accurate matching.
Multi-layered coding of depth for virtual view synthesis

It is well-known that large depth-coding errors typically occurring around depth edge areas lead to distorted object boundaries in the synthesized texture images. This paper proposes a multi-layered coding approach for depth images as a complement to the popular edge-aware approaches such as those based on platelets. It is shown that guaranteeing a near-lossless bound on the depth values around the edges by adding extra enhancement layers is an effective way to improve the visual quality of the synthesized images.
Reduced spatio-temporal transcoding using an intra refresh technique

This paper addresses the problem of transcoding compressed video bitstreams to reduced spatio-temporal resolutions. We propose a new technique to compensate drift error based on the principle of intra-block refresh. We also investigate other important issues related to the transcoding, such as the re-estimation of motion vectors and DCT coefficients. The rate control related to intra-refresh is also addressed. Our experimental results show that the intrarefresh method offers a good trade-off between quality and complexity in comparison to the reference method.
Hiding information inside structured shapes

This paper describes a new technique for embedding a message within structured shapes. It is desired that any changes in the shape owing to the embedded message are invisible to a casual observer but detectable by a specialized decoder. The message embedding algorithm represents shape outlines as a set of cubic Bezier curves and straight line segments. By slightly perturbing the Bezier curves, a single shape can spawn a library of similar-looking shapes each corresponding to a unique message. This library is efficiently stored using Adaptively Sampled Distance Fields (ADFs) which also facilitate rendering of the modified shapes at the desired resolution and fidelity. Given any modified shape, a forensic detector applies Procrustes analysis to determine the embedded message. Results of an extensive subjective test confirm that the shape modifications are indeed unobtrusive. Further, to test the recovery of the message bits in noisy physical environments, a text document is put through a print-photocopy-scan process. Message recovery is found to be stable even after multiple rounds of photocopying.
Robust decoding for reduced error propagation of DC/AC prediction errors

This paper investigates the problem of error propagation in MPEG-4 video decoding when the DCT coefficients have been damaged. The problem is unique since the Intra DC/AC prediction tool adopted by the standard allows for coefficients to be predicted from both the horizontal and vertical directions. Although the standard offers a variety of error resilience techniques to prevent such errors from propagating, they are encoder dependent and one cannot guarantee that suitable encoding parameters have been chosen. Therefore, we propose a robust decoding method that reduces the propagation of such errors.
Motion and Mode Mapping for MPEG-2 to H.264/AVC Transcoding

This paper describes novel low-complexity transcoding techniques for an efficient MPEG-2 to H.264/AVC transcoder. We present a motion and mode mapping algorithm that directly maps incoming MPEG-2 motion information to H.264/AVC motion vectors as well as coding modes. Refinement strategies are also presented to improve performance. Experiment results demonstrate the effectiveness of the proposed low-complexity transcoder
Digital item adaptation: overview of standardization and research activities

MPEG-21 Digital Item Adaptation (DIA) has recently been finalized as part of the MPEG-21 Multimedia Framework. DIA specifies metadata for assisting the adaptation of Digital Items according to constraints on the storage, transmission and consumption, thereby enabling various types of quality of service management. This paper provides an overview of DIA, describes its use in multimedia applications, and reports on some of the ongoing activities in MPEG on extending DIA for use in rights governed environments.
Complexity-quality analysis of transcoding architectures for reduced spatial resolution

This paper presents a detailed complexity-quality analysis of various video transcoding architectures that perform spatial resolution reduction. In addition to a reference architecture, two additional architectures are considered. The reference architecture is a cascaded approach that decodes, down-samples and re-encodes the video. The first additional proposal, intra refresh architecture, compensates for various errors by converting select macroblocks to intra-coded blocks. The second proposal, partial encoder architecture, is similar to the reference, but simplifies the re-encoding process by not compensating for re-quantization errors. The optimization of several processing components, including the down-sampling operation, is presented. We have found that the two additional architectures provide a good trade-off in terms of complexity and quality compared to the reference.
Optimal 2-D interleaving for robust multimedia transmission

Interleaving is a process to rearrange code symbols so as to spread bursts of errors over multiple codewords that can be corrected by random error correction codes (ECCs). By converting bursts of errors into random-like errors, interleaving thus becomes an effective means to combat error bursts. We focus on how to obtain effective interleaving schemes for 2-dimensional (2D) arrays, namely, how to spread the arbitrary error burst such that they are separated as far as possible. To achieve this, the theoretical bound for optimal 2D interleaving on arbitrary sized 2D array is analyzed. Based on it, a novel sphere tiling based method is proposed to achieve this bound. We first present this method for set of specified square array, then we extend it to arbitrary sized 2D array. The validity of the proposed method is proved. By using the proposed method, the multimedia transmission will be more robust against 2D burst error.
Using Distributed Source Coding to Secure Fingerprint Biometrics

We describe a method to encode fingerprint biometrics securely for use, e.g., in encryption or access control. The system is secure because the stored data does not suffice to recreate the original fingerprint biometric. Therefore, a breach in database security does not lead to the loss of biometric data. At the same time the stored data suffices to validate a probe fingerprint. Our approach is based on the use of distributed source coding techniques implemented with graph-based codes. We present a statistical model of the relationship between the enrollment biometric and the (noisy) biometric measurement taking during authentication. We describe how to validate or reject a candidate biometric probe given the probe and the stored encoded data. We report the effectiveness of our method as tested on a database consisting of 579 data sets, each containing roughly 15 measurements of a single finger. We thereby demonstrate a working secure biometric system for fingerprints.
3D-TV Content Storage and Transmission

There exist a variety of ways to represent 3D content, including stereo and multiview video, as well as frame-compatible and depth-based video formats. There are also a number of compression architectures and techniques that have been introduced in recent years. This paper provides an overview of relevant 3D representation and compression formats. It also analyzes some of the merits and drawbacks of these formats considering the application requirements and constraints imposed by different storage and transmission systems.
Independent uniform prediction mode for screen content video coding

Many of the existing video coding standards in use today were developed primarily using camera-captured content as test material. Today, with the more widespread use of connected devices, there is an increased interest in developing video coding tools that target screen content video. Screen content video is often characterized by having sharp edges, noiseless graphics-generated region, repeated patterns, limited sets of colors, etc. This paper presents an independent uniform prediction (IUP) mode for improving the coding efficiency of screen content video. IUP chooses one color out of a small set of global colors to form a uniform prediction block. Unlike existing palette-based modes, IUP does not have to construct and signal a color index map for every block that is coded. Experimental results using IUP in the HEVC Range Extensions 6.0 framework are presented, along with results using techniques that reduce complexity so that the IUP-based encoder is faster than the reference encoder.
Secure function evaluation based on secret sharing and homomorphic encryption

Consider the following problem in secure multiparty computation: Alice and Bob possess integers x and y respectively. Charlie is a researcher who would like to compute the value of some function f(x, y). The requirement is that Charlie should not gain any knowledge about x and y other than that which can be obtained from the function itself. Moreover, Alice and Bob do not trust each other and should not gain knowledge about each other's data. This paper contains initial work on a methodology to enable such secure function evaluation using additive and multiplicative homomorphisms as cryptographic primitives instead of oblivious transfer. It is shown that Charlie can compute the encrypted value of any polynomial in x and y. We present two secure function evaluation protocols for semi-honest participants that can be extended to polynomial functions of an arbitrary number of variables.
Constant quality constrained rate allocation for FGS-coded video

This paper proposes an optimal rate-allocation scheme for fine-granular scalability (FGS) coded bitstreams that can achieve constant quality reconstruction of frames under a dynamic rate budget constraint. In doing so, we also aim to minimize the overall distortion at the same time. To achieve this, we propose a novel rate-distortion (R-D) labeling scheme to characterize the R-D relationship of the source coding process. Specifically, sets of R-D points are extracted during the encoding process and linear interpolation is used to estimate the actual R-D curve of the enhancement-layer signal. The extracted R-D information is then used by an enhancement-layer transcoder to determine the bits that should be allocated per frame. A sliding-window-based rate-allocation method is proposed to realize constant quality among frames. This scheme is first considered for a single FGS-coded source, then extended to operate on multiple sources. With the proposed scheme, the rate allocation can be performed in a single pass; hence, the complexity is quite low. Experimental results confirm the effectiveness of the proposed scheme under static and dynamic bandwidth conditions.
Efficient MPEG-2 to H.264/AVC intra transcoding in transform-domain

In this paper, we propose a transform-domain MPEG-2 to H.264/AVC intra video transcoder. In the transcoder, the input DCT coefficients are first converted to H.264 transform (HT) coefficients entirely in the transform-domain. A rate-distortion optimized macroblock mode decision is then performed, based on the HT coefficients. Finally, the HT coefficients are coded using the selected modes to generate the output H.264 bitstream. The proposed transcoder is equivalent to the conventional pixel-domain implementation in terms of functionality, but its complexity is significantly lower (on average over 20%). To further reduce its computational complexity, we propose a fast mode decision algorithm based on a simple cost function calculated in the HT-domain. This fast algorithm reduces the complexity requirement about 50%, while maintaining virtually the same coding efficiency.
Combined rate control and mode decision optimization for MPEG-2 transcoding with spatial resolution reduction

This paper presents a new algorithm for MPEG-2 transcoding with spatial resolution reduction. The proposed method combines rate control and mode decision to achieve optimal transcoding performance using Lagrange multiplier algorithm. Since the proposed method incorporates motion vector mapping and mode decision into a single Lagrange multiplier formula, by minimizing the Lagrangian cost function, the optimal solution for mode decision can be obtained. The proposed transcoding scheme has demonstrated better subjective and objective results compared with other methods.
Frame-rate up-conversion using transmitted true motion vectors

In this paper, we present a video frame-rate up-conversion scheme that uses transmitted true motion vectors for motion-compensated interpolation. In a past work, we demonstrated that a neighborhood-relaxation motion tracker can provide more accurate true motion information than a conventional minimal-residue block-matching algorithm. Although the technique to estimate the true motion vectors is a novelty in its own right, the strength of this technique can be further demonstrated through various spatio-temporal interpolation applications. In this work, we focus on the particular problem of frame-rate up-conversion. In the proposed scheme, the true motion field is derived by the encoder and transmitted by normal means (e.g., MPEG or H.263 encoding). Then, it is recovered by the decoder and is used not only for motion compensated predictions but also used to reconstruct missing data. It is shown that the use of our neighborhood-relaxation motion estimation provides a method of constructing high quality image sequences in a practical manner.
Standardized Extensions of High Efficiency Video Coding (HEVC)

This paper describes extensions to the High Efficiency Video Coding (HEVC) standard that are active areas of current development in the relevant international standardization committees. While the first version of HEVC is sufficient to cover a wide range of applications, needs for enhancing the standard in several ways have been identified, including work on range extensions for color format and bit depth enhancement, embedded-bitstream scalability, and 3D video. The standardization of extensions in each of these areas will be completed in 2014, and further work is also planned. The design for these extensions represents the latest state of the art for video coding and its applications.