nils-herrmann/clean_scirepeval huggingface dataset:
Techniques for flexible image/video resolution conversion with heterogeneous terminals

Multimedia capturing and display devices of different resolutions and aspect ratios can be easily connected by networks and, thus, there is a great need to develop techniques that facilitate flexible image/video format conversion and content adaptation among these heterogeneous terminals. Quality degradation due to downsampling, up-sampling, coding/decoding, and some content adaptation mechanism (say, image mosaicking) in the transmission process is inevitable. It is desirable that multimedia contents can be easily captured, displayed, and seamlessly composed. Challenges and techniques to achieve this goal are reviewed first. Then, two specific topics, i.e., image/video mosaicking and super resolution (SR) conversion, are highlighted. As compared with previous work developed for these problems, the challenge under the current context is to strike a balance between low computational complexity and high quality of resultant image/video. Several new developments along this line are discussed
WLC22-2: Delay Analysis and Comparison of OFDM-TDMA and OFDMA under IEEE 802.16 QoS Framework

The delay analysis and comparison of OFDM- TDMA and OFDMA using a flow control scheme under the QoS framework of IEEE 802.16 are conducted in this work. We investigate the maximum packet delay performance by deriving delay bounds for several multiaccess modes with different subcarrier/time-slot assignment and bit allocation schemes. The analytical delay bounds provide insights into the performance difference among different multiaccess schemes, and demonstrate each scheme's capability of supporting real-time, delay-sensitive multimedia applications. The derived analytical results are verified by computer simulation.
Robust coding of images using EBCOT and RVLC

EBCOT (embedded block coding with optimized truncation) is an efficient image coding technique adopted by JPEG-2000 VM. EBCOT divides each subband into independently coded 64/spl times/64 blocks, and is therefore inherently more robust to errors than many other wavelet-based schemes. However, loss of data in any lower frequency subband block in EBCOT can still damage the image beyond repair. This work discusses the use of reversible variable length codes (RVLC) for the coding of lower frequency subbands in EBCOT, instead of arithmetic codes. It is demonstrated that RVLCs demand a very low bit-rate overhead.
Coexistence Wi-Fi MAC Design for Mitigating Interference Caused by Collocated Bluetooth

A non-collaborative coexistence mechanism for wireless-fidelity (Wi-Fi) and bluetooth (BT) systems based on dynamic packet fragmentation is proposed in this work. The basic idea is to adapt the packet length of Wi-Fi in the MAC layer such that the fragmented packet has a better chance to survive the interference from the nearby BT devices. We first develop an analytical model that specifies the information required by the Wi-Fi MAC layer to decide the best fragmentation strategy. Then, this model is extended to analyze the throughput and transmission delay of the Wi-Fi device. The analytical model is validated by computer simulation. Furthermore, it is demonstrated by simulation results that the proposed coexistence mechanism improves the performance of Wi-Fi in throughput and transmission delay significantly while relatively smaller performance improvement is observed for BT.
Constant quality rate control for streaming MPEG-4 FGS video

This paper presents a constant quality video rate control (CQVRC) scheme for MPEG-4 FGS (fine-grain scalability) video. The proposed scheme can mitigate quality variations among consecutive frames during the period when there is significant change in the video source or the transmission bandwidth. CQVRC utilizes both non-scalable base layer (BL) and scalable enhancement layer (EL) of MPEG-4 for smoother video quality. To take advantage of the relaxed delay requirement of streaming video, CQVRC for BL exploits a larger decoder buffer, future frame information, and temporal scene segmentation. CQVRC for EL is achieved by embedding one rate-distortion (R-D) pair in each bitplane to construct a piecewise linear R-D model. Experiment results show higher than 1 dB PSNR gain and smaller PSNR variation by comparing the proposed CQVRC with current MPEG-4 FGS VM approach, where BL is encoded with MPEG-4 VM rate control and uniform bit allocation is applied to EL.
Blind delay and DOA estimation in correlated multipath DS-CDMA systems

A joint delay and DOA (direction of arrival) es- timation algorithm in the frequency-selective fading channel with correlated multipaths is proposed for short code DS- CDMA systems in this work. The received 2-D space-time data is first decomposed by a beamforming filterbank. Then, we develop a technique based on zero-forcing equalization (ZFE) to remove the correlated multipaths effect and apply the minimum output energy (MOE) criterion at each beam- forming filter output. The cascaded ZFE/MOE method can estimate multipaths effectively. Finally, the soft-output, which is the estimated power from each beamforming filter output, provides the information for DOA estimation.
Joint quality-temporal (Q-T) bit allocation for H.264/SVC

A joint quality-temporal (Q-T) bit allocation scheme is proposed for H.264/SVC in this work. First, rate and distortion (R-D) models for dependent quality layers are derived, where the complex inter-layer dependency is considered. Then, the joint Q-T bit allocation problem is formulated as an optimization problem using the Lagrange method and solved numerically with the derived R-D models. As a result, we develop a low-complexity bit allocation scheme for the joint Q-T scalability of H.264/SVC. It is demonstrated by experimental results that the new R-D models results in a highly efficient bit allocation scheme, which outperforms the JSVM benchmark by a significant margin.
Perceptual Quality Driven Frame-Rate Selection (PQD-FRS) for High-Frame-Rate Video

Video of higher frame rates (HFR) reduces the visual artifact in large screen display at the cost of a higher coding bit rate (or transmission bandwidth). In this work, we propose a perceptual quality driven frame rate selection (PQD-FRS) method that assigns a time-varying frame rate to a sequence so as to reduce its transmission cost. The objective of the PQD-FRS method is to offer perceptually indistinguishable experience for a certain percentage of viewers. We first conduct a subjective test to characterize the relationship between human perceived quality and video contents, and build a frame-rate-dependent video quality assessment dataset to serve as the ground truth. Then, we use a machine learning approach for the design of the key module of the PQD-FRS method, called the “satisfied user ratio (SUR) prediction.” The SUR prediction module predicts the percentage of satisfied viewers, who cannot differentiate video quality of a lower and HFR, using the support vector regression. It is confirmed by experimental results that the proposed SUR module can offer a so highly accurate prediction that the PQD-FRS system can dynamically assign a proper frame rate to video without any perceptual quality degradation for a majority of viewers.
Progressive geometry encoder using octree-based space partitioning

A progressive 3D geometry coding scheme using octree-based space partitioning is proposed in this work, which achieves better coding efficiency than the state-of-the-art geometric codec known as the kd-tree-based codec. Given a 3D mesh, the quantized 3D vertices are first partitioned into an octree structure. The octree is then traversed from the root and gradually to the leaves and, during the traversal, each 3D cell in the tree front is subdivided along three orthogonal directions. For each cell subdivision, an 8-bit bitpattern is generated, reordered, and entropy encoded. Furthermore, selective cell subdivision is performed to provide better rate-distortion performance, especially at low bitrates. It is shown in experimental results that the coding cost is around 5.5 bits per vertex (bpv) for 8-bit coordinate quantization and 16.6 bpv for 12-bit coordinate quantization on the average. The rate-distortion performance of the proposed algorithm is significantly better than that of the kd-tree-based codec, especially at low bitrates.
Sparse/DCT (S/DCT) Two-Layered Representation of Prediction Residuals for Video Coding

In this paper, we propose a cascaded sparse/DCT (S/DCT) two-layer representation of prediction residuals, and implement this idea on top of the state-of-the-art high efficiency video coding (HEVC) standard. First, a dictionary is adaptively trained to contain featured patterns of residual signals so that a high portion of energy in a structured residual can be efficiently coded via sparse coding. It is observed that the sparse representation alone is less effective in the R-D performance due to the side information overhead at higher bit rates. To overcome this problem, the DCT representation is cascaded at the second stage. It is applied to the remaining signal to improve coding efficiency. The two representations successfully complement each other. It is demonstrated by experimental results that the proposed algorithm outperforms the HEVC reference codec HM5.0 in the Common Test Condition.
Rate control for an embedded wavelet video coder

Embedded coders provide a better rate-distortion tradeoff while the coded bit stream can be truncated at any point without a significant perceptible distortion. We investigate rate control for an embedded wavelet video coder by converting the rate control problem to a bit allocation problem for each frame. Then, a computationally efficient rate control algorithm is derived by exploiting the rate-distortion performance of the embedded wavelet coder and the frame dependency between the reference frame and the predictive frame. Experiments are performed to demonstrate the superior performance of the embedded wavelet video coder with the proposed rate control scheme. It is shown that the proposed rate control strategy outperforms the fixed allocation rate control by 0.1-0.4 dB for a variety of sequences, and the performance gain can be as large as 1.3-2.7 dB around scene changes.
Layered DCT still image compression

Motivated by Shapiro's (1993) embedded zerotree wavelet (EZW) coding and Taubman and Zakhor's (1994) layered zero coding (LZC), we propose a layered discrete cosine transform (DCT) image compression scheme, which generates an embedded bit stream for DCT coefficients according to their importance. The new method allows progressive image transmission and simplifies the rate-control problem. In addition to these functionalities, it provides a substantial rate-distortion improvement over the JPEG standard when the bit rates become low. For example, we observe a bit rate reduction with respect to the JPEG Huffman and arithmetic coders by about 60% and 20%, respectively, for a bit rate around 0.1 b/p.
Decode-and-Forward Cooperative Relay with Multi-User Detection in Uplink CDMA Networks

The use of multi-user detection (MUD) in a cooperative CDMA network is investigated for the uplink in synchronous CDMA systems. Suppose that, at any instant in time, part of the users serve as sources while the others serve as relays. The proposed MUD scheme decorrelates the sources' messages at the destination with the help of precoding at the relays. Three cooperation methods are considered: (1) transmit beamforming, (2) selective relaying and (3) distributed space- time coding. The optimal weighting factors of each method are determined by taking the quality of the source-to-relay and/or the relay-to-destination links into account. We show that significant improvements in terms of the spatial diversity and multiple-access interference (MAI) mitigation can be attained when precoding is employed at the relays to aid the decorrelation at the destination. The advantages are even more pronounced when selective relaying is combined with the other two schemes.
Image segmentation using contour, surface, and depth cues

We target at solving the problem of automatic image segmentation. Although 1D contour and 2D surface cues have been widely utilized in existing work, 3D depth information of an image, a necessary cue according to human visual perception, is however overlooked in automatic image segmentation. In this paper, we study how to fully utilize 1D contour, 2D surface, and 3D depth cues for image segmentation. First, three elementary segmentation modules are developed for these cues respectively. The proposed 3D depth cue is able to segment different textured regions even with similar color, and also merge similar textured areas, which cannot be achieved using state-of-the-art approaches. Then, a content-dependent spectral (CDS) graph is proposed for layered affinity models to produce the final segmentation. CDS is designed to build a more reliable relationship between neighboring surface nodes based on the three elementary cues in the spectral graph. Extensive experiments not only show the superior performance of the proposed algorithm over state-of-the-art approaches, but also verify the necessities of these three cues in image segmentation.
Efficient segmentation-aided text detection for intelligent robots

Scene text detection is a critical prerequisite for many fascinating applications for vision-based intelligent robots. Existing methods detect texts either using the local information only or casting it as a semantic segmentation problem. They tend to produce a large number of false alarms or cannot separate individual words accurately. In this work, we present an elegant segmentation-aided text detection solution that predicts the word-level bounding boxes using an end-to-end trainable deep convolutional neural network. It exploits the holistic view of a segmentation network in generating the text attention map (TAM) and uses the TAM to refine the convolutional features for the MultiBox detector through a multiplicative gating process. We conduct experiments on the large-scale and challenging COCO-Text dataset and demonstrate that the proposed method outperforms state-of-the-art methods significantly.
An iterative approach to frequency offset estimation for multicarrier communication systems

An iterative approach to estimate the carrier frequency offset in multicarrier communication systems is proposed in this work. Based on the previous estimated channel coefficients and provided a sufficiently large number of subcarriers, an approximate maximum likelihood (ML) estimate of the normalized frequency offset, which in turn can be used to refine the previous obtained estimation of channel coefficients. Simulation results show that the proposed algorithm requires a reliable estimation of the channel fading coefficients. Through a fast acquisition of the frequency offset at the beginning symbol block of each frame, the proposed iterative process can be better initiated, and the possible drift of the carrier frequency offset can therefore be tracked accurately.
A spatial-domain error concealment method with edge recovery and selective directional interpolation

A low complexity spatial-domain error concealment method is proposed to reconstruct still images and intra-coded (I) frames in video when they are transmitted through unreliable channels in this work. The proposed concealment algorithm works with the following steps. First, missing edges in a lost macroblock (MB) are detected and recovered using gradient data. Then, the lost MB is implicitly divided into several segments along the recovered edges. Finally, each pixel in a segment is directionally interpolated from boundary pixels adjacent to the segment. Experimental results show that the proposed algorithm can recover high as well as low frequency information in lost MBs and provide better visual quality in comparison with the conventional spatial domain interpolation.
Fundamental frequency estimation for music signals with modified Hilbert-Huang transform (HHT)

In this work, we propose a modified Hilbert-Huang transform (HHT) method to detect low pitch musical signals within a short analysis temporal window for real-time fundamental frequency estimation. HHT is a non-linear method which is suitable for the analysis of non-stationary AM/FM like data. However, to apply HHT directly to music signals encounters several problems. Here, we modify HHT so that it can be tailored to the short-window pitch analysis. It is shown by experimental results that the proposed HHT method performs significantly better than several benchmark schemes.
Fractal wavelet coding using a rate-distortion constraint

We propose a hybrid fractal wavelet coder (FWC) which adopts adaptive fractal prediction in the wavelet domain and wavelet coding in this research. This new compression scheme uses wavelet coding as the core component, and applies contractive mapping (or the so-called fractal prediction) whenever it offers additional rate savings. A model based rate-distortion (R-D) criterion of low complexity is used to evaluate the fractal prediction efficiency and search for the best domain-range match. The superior R-D performance of FWC is demonstrated with extensive experimental results.
Multiscale video compression using wavelet transform and motion compensation

A new framework for multiscale video coding is proposed in this research with the objective to achieve efficient video coding with spatial scalability. In this framework, multiscale motion compensation is performed to remove temporal redundancy, and both the motion field and the displacement frame difference (DFD) are compressed via wavelet transform, successive embedded quantization and entropy coding for multiscale representation and decoding. The proposed new method does not only secure the prediction loop of lower resolution video but also provides an efficient prediction from coarser to finer resolutions.
Low complexity binary description wavelet codec

This paper presents a new coding algorithm, called the low complexity binary description (LCBiD) wavelet coder, which has an extremely low implementation complexity yet very rich features. LCBiD encodes wavelet coefficients in blocks of fixed size (16,16). Wavelet coefficients of a block are only taken from a single subband. No inter-subband correlation is exploited so that no specific requirement is imposed on how wavelet coefficients are generated. Each block is encoded using binary context-based bitplane coding. A (16,16) block is usually much smaller than a subband, and a block can become significant much later than a subband. A block skipping technique is employed to bypass one layer of zeros if a block is insignificant at the current quantization threshold. In other words, a separate bitstream is generated to describe the significance of blocks. Because much less zeros are encoded, both the coding speed and efficiency are increased greatly. A separate arithmetic coder set is used for each bitplane, and all coders are reset at the beginning of each subband. Thus, each bitplane of every subband in the compressed file can be directly accessed, and decoded almost independently. The only constraint is that all bitplanes of one subband must be decoded in the correct order. In order to reduce the overall number of arithmetic coders, very simple coding contexts are defined. The image codec has a very good coding performance, and the compressed file is quality and resolution scalable, and resilient to transmission errors.
Distortion-Aware Multimedia Authentication using an Enhanced Hash Function

A new type of hash function called the distance preserving (DP) hash function is proposed to tackle the shortcoming of the traditional bit-wise multimedia authentication scheme. A DP hash function accepts two inputs: the message and a security key. It is indistinguishable from a conventional hash function under different security keys. However, if the same security key is applied, the DP hash function yields the distance information between the original and the distorted inputs. In other words, the distortion is only accessible to legitimate users knowing the correct key and will not be revealed to any unauthorized party. We study the properties of the DP hash function and provide an example for its construction. A generalized framework for distortion-aware multimedia authentication using the DP hash function is proposed where users can evaluate the content distortion and render the authenticity degree. Experiments are conducted to demonstrate the effectiveness of the DP hash function for multimedia authentication
Progressive coding of 3D textured graphic model via joint mesh-texture optimization

Progressive coding of 3D textured graphic models using a joint mesh-texture optimization technique is investigated in this work. The mesh and texture data of a model are first fed into their respective compression modules to result in a series of levels of details. Then, for a given viewpoint, a rate-distortion surface is generated using these mesh and texture data. Afterwards, an optimal path over the rate-distortion surface is determined by the steepest descent algorithm. To achieve progressive transmission, the mesh and texture are transmitted in a certain ratio along the optimal path to provide the best visual quality for the given viewpoint. For further generalization, a layered sampling algorithm is proposed to deal with an arbitrary viewing angle. The performance of the proposed joint mesh-texture progressive coding algorithm is demonstrated by experimental results.
Wavelet coefficient computation with optimal prefiltering

Discrete wavelet transform (DWT) is often used to approximate wavelet series transform (WST) and continuous wavelet transform (CWT), since it can be computed numerically. In this research, we first study the accuracy of the computed DWT coefficients obtained from the Shensa (see ibid., vol.40, no.10, p.2464-2482, 1992) algorithm as an approximate of the WST coefficients. Based on the accuracy analysis, we then propose a procedure to design optimal FIR prefilters used in the Shensa algorithm to reduce the approximation error. Finally, numerical examples are presented to demonstrate the performance of the optimal FIR prefilters.
Error-resilient coding of 3-D graphic models via adaptive mesh segmentation

Current coding techniques for 3-D graphic models mainly focus on coding efficiency, which makes them extremely sensitive to channel errors due to the irregular mesh structure. We introduce a new approach for error-resilient coding of arbitrary 3-D graphic models by extending the error-free constructive traversal compression scheme proposed by Li and Kuo (see MPEG-4 Tokyo Meeting, 1998, , and Proc.  vol.86, p.1052-63, 1998). A 3-D mesh of an arbitrary structure is partitioned into pieces of a smaller uniform size with joint boundaries. The size of a piece is determined adaptively based on the channel error rate. The topology and geometry information of each joint boundary and each piece of a connected component is coded independently. The coded topology and first several important bit-planes of the joint-boundary data are protected against channel errors by using the Bose-Chaudhuri-Hocquenghem error-correcting code. At the decoder, each piece is decoded and checked for channel errors. The decoded joint-boundary information is used to perform data recovery and error concealment on the corrupted piece data. All decoded pieces are combined together according to their configuration to reconstruct all connected components of the complete 3-D model. Our experiments demonstrate that the proposed approach has excellent error resiliency at a reasonable bit-rate overhead. The techniques is also capable of incrementally rendering one connected component of the 3-D model at a time.