nils-herrmann/clean_scirepeval huggingface dataset:
Protocols for distributed video streaming

With the explosive growth of video applications over the packet switched networks, many approaches have been proposed to stream video effectively over packet switched, best-effort networks. In our previous work, we proposed a framework with a receiver driven protocol to coordinate simultaneous video streaming from multiple senders to a single receiver in order to achieve higher throughput, and to increase tolerance to packet loss and delay due to network congestion. The receiver-driven protocol employs two algorithms: the rate allocation and packet partition. The rate allocation algorithm determines the sending rate for each sender while the packet partition algorithm ensures no sender sends the same packets, and at the same time, minimizes the probability of late packets. We extend the rate allocation scheme to be used with forward error correction (FEC) in order to minimize the probability of packet loss in a bursty loss environment such as one due to network congestion. Using both simulations and actual Internet experiments, we demonstrate the effectiveness of our rate allocation scheme in reducing packet loss, and hence, achieving higher visual quality for the streamed video.
Capturing 2&#189;D Depth and Texture of Time-Varying Scenes Using Structured Infrared Light

In this paper, we describe an approach to simultaneously capture visual appearance and depth of a time-varying scene. Our approach is based on projecting structured infrared (IR) light. Specifically, we project a combination of (a) a static vertical IR stripe pattern, and (b) a horizontal IR laser line sweeping up and down the scene; at the same time, the scene is captured with an IR-sensitive camera. Since IR light is invisible to the human eye, it does not disturb human subjects or interfere with human activities in the scene; in addition, it does not affect the scene’s visual appearance as recorded by a color video camera. Vertical lines in the IR frames are identified using the horizontal line, intra-frame tracking, and inter-frame tracking; depth along these lines is reconstructed via triangulation. Interpolating these sparse depth lines within the foreground silhouette of the recorded video sequence, we obtain a dense depth map for every frame in the video sequence. Experimental results corresponding to a dynamic scene with a human subject in motion are presented to demonstrate the effectiveness of our proposed approach.
Halftone to continuous-tone conversion of error-diffusion coded images

The problem of reconstructuring a continuous-tone (cotone) image from its error-diffused halftoned version is presented. The authors present a POCS (projection onto convex sets)-based iterative nonlinear algorithm for this problem, and show simulation results that compare the performance of the algorithm with that of conventional linear lowpass filtering. It is found that the proposed technique results in subjectively superior reconstruction. As there is a natural relationship between error diffusion and sigma-delta modulation, the proposed reconstruction algorithm can also be applied to the decoding problem for sigma-delta modulators.<<ETX>>
OPTIMAL DECODING FOR DATA ACQUISITION APPLICATIONS OF SIGMA DELTA MODULATORS

We propose a class of optimal decoding algorithms for data acquisition applications of Sigma Delta (EA) modulators. Our technique is applicable to all current EA structures, including single and double loop, cascade and interpolative modulators. While the performance of our technique is identical to that of other optimal nonlinear decoding schemes such as table look-up, it is considerably simpler to implement. Simulation results are presented to compare the performance of our decoding technique to that of linear decoders.
Adaptive modulus quantizer design for matching pursuit video coding

Overcomplete signal decomposition using matching pursuits has been shown to be an efficient technique for coding motion residual images in a hybrid video coder. Unlike orthogonal decomposition where computation of the transform coefficients is decoupled from quantization, matching pursuit uses an in-loop quantizer which must be specified before coding begins. Optimal quantizer design thus depends on the computed matching pursuit coefficients, but these in turn depend on the chosen quantizer. To resolve this interdependency, we propose frame-adaptive quantization for matching pursuit based on adaptive dead-zone subtraction followed by uniform threshold quantization. Practical 2-pass and 1-pass algorithms are developed which jointly find the quantizer parameters and the number of coded basis functions which minimize coding distortion for a given rate. The compromise 1-pass scheme performs nearly as well as the full 2-pass algorithm, but with the same complexity as a fixed quantizer design. The adaptive schemes are shown to outperform the fixed quantizer used in earlier works, especially at high bit rates where the gain is up to 1.7 dB.
Rate and resolution scalable subband coding of video

We propose a full colour video compression strategy, based on 3-D subband coding with camera pan compensation, to generate a single, embedded, compressed bit stream supporting multiple decoder display formats and a wide, finely gradated range of bit rates. An experimental implementation of our algorithm produces a single bit stream, from which suitable subsets are extracted to be compatible with many useful decoder frame sizes and frame rates and to satisfy transmission bandwidth constraints ranging from several tens of kilo-bits per second to several mega-bits per second. The reconstructed video quality from any of these bit stream subsets is often found to exceed that obtained from an MPEG-1 implementation, operated with equivalent bit rate constraints, in both perceptual quality and mean squared error.<<ETX>>
Systematic design of phase-shifting masks with extended depth of focus and/or shifted focus plane

An optimization based algorithm for designing phase-shifting masks is proposed. The approach is an extension of the previous work in the sense that the intensity image is optimized at a number of optical planes rather than just the focus plane. In addition, the algorithm can be used to design masks with shifted focus plane and/or extended depth of focus. The concept of a dual mask is introduced, and its consequences for practical phase-shifting mask design are shown. The proposed design techniques are applied to single line phase connectors, cross phase connectors, contact holes and bright lines. Simulation and experimental results verify the capability of the design technique for extending depth of focus and shift the focus plane.
Tones, saturation, and SNR in double loop /spl Sigma//spl Delta/ modulators

Two of the most important factors affecting the performance of oversampled A/D converters are tone, and saturation considerations. Tradeoffs between the above factors for /spl Sigma/-/spl Delta/ modulators are analyzed. The effects of pole placement on the steady state behavior of /spl Sigma/-/spl Delta/ modulators are investigated by studying the dynamics of an associated continuous time system.<<ETX>>
Tree Detection in Aerial Lidar and Image Data

In this paper, we present an approach to detecting trees in registered aerial image and range data obtained via LiDAR. The motivation for this problem comes from automated 3D city modeling, in which such data is used to generate the models. Representing the trees in these models is problematic because the data is usually too sparsely sampled in tree regions to create an accurate 3-D model of the trees. Furthermore, including the tree data points interferes with the polygonization step of the building roof top models. Therefore, it is advantageous to detect and remove points that represent trees in both LiDAR and aerial imagery. In this paper we propose a two-step method for tree detection consisting of segmentation followed by classification. The segmentation is done using a simple region-growing algorithm using weighted features from aerial image and LiDAR, such as height, texture map, height variation, and normal vector estimates. The weights for the features are determined using a learning method on random walks. The classification is done using weighted support vector machines (SVM), allowing us to control the mis-classification rate. The overall problem is formulated as a binary detection problem, and receiver operating characteristic curves are shown to validate our approach.
AIO-TFRC: a light-weight rate control scheme for streaming over wireless

Rate control is an important issue in video streaming applications for both wired and wireless networks. A widely accepted rate control method in wired networks is TCP friendly rate control (TFRC). TFRC assumes that packet loss in wired networks is primarily due to congestion, and as such is not directly applicable to wireless networks in which the main cause of packet loss is at the physical layer. In our previous work, we proposed MULTFRC as an end-to-end based solution to this problem. By opening appropriate number of TFRC connections, MULTFRC not only avoids modifications to the network infrastructure or protocol stack, but also results in full utilization of the wireless channel. In this paper, we propose an alternative end-to-end approach to MULTFRC, denoted by AOI-TFRC. AIO-TFRC enjoys all the advantages of MULTFRC except that it combines multiple connections into one connection in order to reduce implementation complexity, and undesirable consequences of "quantization effect" associated with MULTFRC. NS-2 simulations are carried out to characterize AIO-TFRC's performance, and to show its fairness with respect to TCP. The reduced complexity of AIO-TFRC makes it appealing for actual implementations on mobile handheld devices.
Two-dimensional polynomial interpolation from nonuniform samples

A number of results are presented concerning sufficient conditions under which the two-dimensional (2-D) polynomial interpolation problem has a unique or nonunique solution. It is found that unless an appropriate number of interpolation points are chosen on an appropriate number of irreducible curves, the resulting problem might become singular. Specifically, if the sum of the degrees of the irreducible curves on which the interpolation points are chosen is small compared to the degree of the interpolating polynomial, then the problem becomes singular. Similarly, if there are too many points on any of the irreducible curves on which the interpolation points are chosen, the interpolation problem runs into singularity. Examples of geometric distributions of interpolation points satisfying these conditions are shown. The examples include polynomial interpolation of polar samples, and samples on straight lines. The author proposes a recursive algorithm for a class of interpolation points.<<ETX>>
Foreground/background Separation Via Camera Motion Estimation

Camera motion estimation is an important step in the compression of video sequences taken with a real camera. By obtaining zoom and pan parameters that account for camera translation, rotation and change of focus, it is possible to devote all the subsequent compression efforts on the coding of the foreground motion. In this paper, we propose a new approach to zoom and pan detection. First, the images are processed by an edge detection algorithm. Then, features are matched in subsequent frames of the sequence and zoom and pan parameters are obtained by minimizing the error between the matches found and the matches that would have been found in presence of only zoom and pan. This approach offers several advantages. First, on a serial machine such as Sparc I1 workstation, it is an order of magnitude faster than zoom and pan detection algorithms based on traditional Block Matching Algorithms. Second, the edge image and the matching coordinates can be used to code the movement other than zoom and pan. Third, the minimum square error approach is very convenient computationally and guarantees the best prediction of the parameters. Once zoom and pan parameters are determined, the frame difference between the actual next frame and its prediction based on zoom and pan parameters essentially contains foreground motion. To examine the effectiveness of our foreground/background separation technique, we apply our algorithm to two sequences: a high resolution "MIT" sequence where only zoom and pan are present, and a "ping-pong" sequence where foreground motion is also present. Our data also shows that zoom and pan parameters can be estimated considerably more accurately, if the motion vectors are determined to sub pixel accuracy. This is achieved by interpolating the images before passing them through the edge detector.
Geometric calibration for a multi-camera-projector system

In this paper, we describe a calibration method for multi-camera-projector systems in which sensors face each other as well as share a common viewpoint. We use a translucent planar sheet framed in PVC piping as a calibration target which is placed at multiple positions and orientations within a scene. In each position, the target is captured by the cameras while it is being illuminated by a set of projected patterns from various projectors. The translucent sheet allows the projected patterns to be visible from both sides, allowing correspondences between devices that face each other. The set of correspondences generated between the devices using this target are input into a bundle adjustment framework to estimate calibration parameters. We demonstrate the effectiveness of this approach on a multiview structured light system made of three projectors and nine cameras.
Spectral characteristics of the double-loop sigma-delta modulator

An important factor affecting the performance of /spl Sigma//spl Delta/ modulators is their tone behavior. A recent approach to alleviate the tone problem consists of moving the open-loop poles outside the unit circle. In this paper, we determine the frequency location of two dominant tones as a function of pole-location, and discuss the effect of pole location on the relative amplitude of low-frequency tones. Audio testing along with a series of simulations are then performed to compare the efficacy of pole placement with that of the more traditional tone removal technique of dithering.
Admissions control and data placement for VBR video servers

In this paper we compare techniques for storage and real-time retrieval of variable bit rate (VBR) video data for multiple simultaneous users. We compare two main classes of data placement techniques: constant time length (CTL) and constant data length (CDL). For each technique, we consider both deterministic and statistical admissions control policies and show that the statistical policies are more suitable for interactive applications. CDL-based data placement is shown to be able to achieve lower overload probabilities than CTL-based ones for a given user distribution at the expense of a much higher buffer requirement and higher delays. A "burst mode" technique for CDL is discussed that can reduce the delays at the expense of even higher buffer usage. We verify our theoretical overload probabilities for the statistical admissions control policies with experiments run on a discrete event simulator.<<ETX>>
Rate- and resolution-scalable video and image compression with subband coding

Proposes a full colour video compression strategy, based on 3D subband coding with camera pan compensation, to generate a single embedded bit stream supporting multiple decoder display formats and a wide, finely gradated range of bit rates. An experimental implementation of the algorithm produces a single bit stream, from which suitable subsets are extracted to be compatible with many useful decoder frame sizes and frame rates and to satisfy transmission bandwidth constraints ranging from several tens of kilobits per second to several megabits per second. Reconstructed video quality from any of these bit stream subsets is often found to exceed that obtained from an MPEG-1 implementation, operated with equivalent bit rate constraints, in both perceptual quality and mean squared error. In addition, when restricted to two dimensions, the algorithm produces some of the best results available in still image compression.<<ETX>>
Iterative procedures for reduction of blocking effects in transform image coding

The authors propose an iterative block reduction technique based on the theory of a projection onto convex sets. The idea is to impose a number of constraints on the coded image in such a way as to restore it to its original artifact-free form. One such constraint can be derived by exploiting the fact that the transform-coded image suffering from blocking effects contains high-frequency vertical and horizontal artifacts corresponding to vertical and horizontal discontinuities across boundaries of neighboring blocks. Another constraint has to be with the quantization intervals of the transform coefficients. Specifically, the decision levels associated with transform coefficient quantizers can be used as lower and upper bounds on transform coefficients, which in turn define boundaries of the convex set for projection. A few examples of the proposed approach are presented.
Error control for video multicast using hierarchical FEC

Bit-rate scalable video compression with layered multicast has been shown to be an effective method to achieve rate control in heterogeneous networks. We further propose the use of hierarchical FEC as an error control mechanism that allows receivers to individually trade-off latency for received video quality. The scheme is efficient since FEC packets are used to protect only the more important data layers and is multicast only to receivers that need them, thereby improving network utilization. Furthermore, there is no loss in error correcting capability by using hierarchical FEC when maximum distance separable codes are used. Actual MBONE experiments are performed to evaluate the performance of the proposed scheme.
Effective bandwidth based scheduling for streaming media

We propose a class of rate-distortion optimized packet scheduling algorithms for streaming media by generating a number of nested substreams, with more important streams embedding less important ones in a progressive manner. Our goal is to determine the optimum substream to send at any moment in time, using feedback information from the receiver and statistical characteristics of the video. To do so, we model the streaming system as a queueing system, compute the run-time decoding failure probability of a group of picture in each substream based on effective bandwidth approach, and determine the optimum substream to be sent at that moment in time. We evaluate our scheduling scheme with various video traffic models featuring short-range dependency (SRD), long-range dependency (LRD), and/or multifractal properties. From experiments with real video data, we show that our proposed scheduling scheme outperforms the conventional sequential sending scheme.
Experimental results on reconstruction of complex multidimensional signals from Fourier transform magnitude

Reconstruction of multidimensional signals from Fourier transform magnitude (FTM) is viewed as a special case of the reconstruction of a complex signal from the FTM and space domain phase, with the phase being equal to zero or pi . Specifically, pixels above the threshold used for one bit quantization can be thought of as having zero phase, and the ones below it can be considered to have pi phase. In a similar fashion, the problem of reconstruction of real images from FTM can be considered to be a special case of the reconstruction of complex signals from the FTM and space domain phase, with the phase being equal to zero. The author's experimental results indicate that the former reconstruction problem with binary phase is considerably more robust than the latter one with zero phase. Thus, an interesting question to examine would be whether reconstruction of a complex signal from FTM and space-domain phase becomes better conditioned as the space domain phase becomes more randomized. The author's preliminary experiments show that reconstruction from FTM and space domain random phase with uniform probability distribution function results in excellent reconstruction quality, and that the relative importance of FTM information with respect to Fourier transform phase information increases as the randomness of the phase of the complex multidimensional signal in space domain increases.<<ETX>>
Subband video coding based on velocity filters

The authors propose a new three-dimensional subband decomposition system for video coding applications. The basic idea is to modify traditional 3D systems so as to separate motion along opposite directions. The decomposition exploits the velocity discrimination capability of the human eye, and results in a more physically meaningful partition than traditional systems. The proposed system consists of a number of two band one-dimensional perfect reconstruction filters together with a number of two band checker board two-dimensional filters. Using synthetic and real sequences, the capability of the system to separate the direction of motion was demonstrated.<<ETX>>
Sensor fusion for semantic segmentation of urban scenes

Semantic understanding of environments is an important problem in robotics in general and intelligent autonomous systems in particular. In this paper, we propose a semantic segmentation algorithm which effectively fuses information from images and 3D point clouds. The proposed method incorporates information from multiple scales in an intuitive and effective manner. A late-fusion architecture is proposed to maximally leverage the training data in each modality. Finally, a pairwise Conditional Random Field (CRF) is used as a post-processing step to enforce spatial consistency in the structured prediction. The proposed algorithm is evaluated on the publicly available KITTI dataset  , augmented with additional pixel and point-wise semantic labels for building, sky, road, vegetation, sidewalk, car, pedestrian, cyclist, sign/pole, and fence regions. A per-pixel accuracy of 89.3% and average class accuracy of 65.4% is achieved, well above current state-of-the-art .
Capturing 2 1/2 D depth and texture of time-varying scenes using structured infrared light

In this paper, we describe an approach to simultaneously capture visual appearance and depth of a time-varying scene. Our approach is based on projecting structured infrared (IR) light. Specifically, we project a combination of (a) a static vertical IR stripe pattern, and (b) a horizontal IR laser line sweeping up and down the scene; at the same time, the scene is captured with an IR-sensitive camera. Since IR light is invisible to the human eye, it does not disturb human subjects or interfere with human activities in the scene; in addition, it does not affect the scene's visual appearance as recorded by a color video camera. Vertical lines in the IR frames are identified using the horizontal line, intra-frame tracking, and inter-frame tracking; depth along these lines is reconstructed via triangulation. Interpolating these sparse depth lines within the foreground silhouette of the recorded video sequence, we obtain a dense depth map for every frame in the video sequence. Experimental results corresponding to a dynamic scene with a human subject in motion are presented to demonstrate the effectiveness of our proposed approach.
Ghost cancellation algorithms for MRI images

Ghost cancellation algorithms for restoring magnetic resonance imaging (MRI) images in medical applications are described. The approach is to model the effect of the time delays and the asymmetry of the sinusoidal readout gradient for even and odd lines with two phase functions relating the actual object density to even and odd parts of the observed image. A priori information about the phase functions is exploited in order to estimate the true object density. Examples of applying this ghost cancellation approach to liver and heart images is presented.