nils-herrmann/clean_scirepeval huggingface dataset:
Coding strategies and performance analysis of GPU accelerated image compression

Graphics Processing Units (GPUs) are freely programmable massively parallel general purpose processing units and thus offer the opportunity to off-load heavy computations from the CPU to the GPU. One application for GPU programming is image compression, where the massively parallel nature of GPUs promises high speed benefits. However, measurements with competative highly optimized CPU implementations show that GPU based codes are usually not considerably faster, or perform only with less than ideal rate-distortion performance. This article presents the predicaments of data-parallel image coding by first presenting a series of theoretical arguments that limit the performance of such implementations before advancing to existing GPU implementations demonstrating the challenges of parallel image coding. It will be argued and seen on experiments that either parts of the entropy coding and bitstream build-up must remain serial, or rate-distortion penalties must be paid when offloading all computations on the GPU.
JPEG on STEROIDS: Common optimization techniques for JPEG image compression

Despite its age, JPEG (formally, Rec. ITU-T T.81 - ISO/IEC 10918-1) is still the omnipresent image file format for lossy compression of photographic images. While its rate-distortion performance is not competitive with state-of-the-art schemes like JPEG 2000 or HEVC, manifold techniques have been developed over the years to improve its compression performance. This article provides a short review of the known technologies and evaluates them on the basis of the JPEG XT demo implementation available on the home page of the JPEG committee. It also puts the compression gains into perspective of more modern compression formats such as JPEG 2000.
Super-resolution for mixed-resolution multiview images using a relative frequency response estimation method

In mixed-resolution multiview setups, spatially neighboring high-resolution views can be used to increase the image quality of an intermediate low-resolution camera perspective. By utilizing corresponding depth data, high-frequency information can be projected from the reference perspectives onto the image plane of the low-resolution view, creating the desired super-resolved image. In this context, the high-frequency part is extracted by subtracting an estimated low-resolution image from a high-resolution reference view. Starting from this, an approach is proposed that aims at first estimating the frequency responses of the involved cameras. As a consequence, the low-frequency part of a neighboring view can be adapted to the image characteristics of the intermediate low-resolution camera perspective. Exploiting this knowledge, the approach finally leads to a high-frequency part that better fits the target low-resolution view and thus to a better super-resolution quality. For a downsampling factor of 4, the proposed estimation leads to an average gain of 0.53 dB.
Distributed 1-Tb/s all-optical aggregation capacity in 125-GHz optical bandwidth by frequency conversion in fiber

We demonstrate the spatially distributed aggregation of four 31.1-GBd PDM-32QAM sub-carriers into a 1-Tb/s net data rate superchannel occupying only 125-GHz optical bandwidth, and its subsequent transmission over 160-km SSMF with broadband reception in a single coherent receiver.
A rig booking system for on-line laboratories

Recently, many educational institutions have acknowledged the importance of making laboratories available on-line, allowing their students to run experiments from a remote computer. While usage of virtual laboratories scales well, remote experiments, based on scarce and expensive rigs, i.e. physical resources, do not and typically can only be used by one person or cooperating group at a time. It is therefore necessary to administer the access to rigs, where we distinguish between three different roles: content providers, teachers and students. This paper reports on a conceptual model and technical design of a rig booking system that provides mechanisms for content providers and teachers to control and grant access to on-line remote laboratories. The design of the booking system is based on a requirements analysis carried out by the EC funded LiLa project in cooperation with international partners from the Global Online Lab Consortium, GoLC.
Integrating an online programming lab into ILIAS

Numerical Mathematics and knowledge of elementary computer algorithms are essential parts of any engineering education. While our university provided access to computer programming languages and computer algebra systems, their installation on the students home computer often turned out to be a challenge and solving installation problems required an essential time of any freshmen course. To overcome these problems, the University of Stuttgart developed an online web-based programming tool, the VipLab, which allows hosting manifold computer programming systems from C to MATLAB while providing a simple online development environment to students. In the past, this programming lab was based on SCORM modules, following our own conventions defined in the LiLa project. However, SCORM has a couple of limitations, too, and the overall weak integration requires a needlessly complicated workflow for both lecturers creating exercises and students handing in homework solutions. In this work, we describe these limitations and how to overcome them by a solution specific to the Learning Management System (LMS) used at the University of Stuttgart.
Evaluation of floating point image compression

Recently, compression of High Dynamic Range (HDR) photography gained attention in the standardization of the Microsoft HDPhoto compression scheme as JPEG-XR. While integer data of 16 bits/pixel (bpp) in scRGB color-space can represent images up to a dynamic range of about 3.5 magnitudes in luminance, even higher ranges are more efficiently represented by floating-point number formats. In this work, the author presents the approach taken by JPEG-XR for compressing such data, and shows that this method when applied to JPEG 2000 generates equally good results. Furthermore, it is shown that the method performs nearly optimal under a mathematical quality index that is closely related to SSIM, and to the mean square error of the HDR images when rendered to the LDR regime.
Spatio-temporal prediction in video coding by non-local means refined motion compensation

The prediction step is a very important part of hybrid video codecs. In this contribution, a novel spatio-temporal prediction algorithm is introduced. For this, the prediction is carried out in two steps. Firstly, a preliminary temporal prediction is conducted by motion compensation. Afterwards, spatial refinement is carried out for incorporating spatial redundancies from already decoded neighboring blocks. Thereby, the spatial refinement is achieved by applying Non-Local Means de-noising to the union of the motion compensated block and the already decoded blocks. Including the spatial refinement into H.264/AVC, a rate reduction of up to 14 % or respectively a gain of up to 0.7 dB PSNR compared to unrefined motion compensated prediction can be achieved.
Supporting Feature Estimation with Risk and Effort Annotations

The accuracy of effort estimates is an important factor for the success of a project. In agile projects, these estimates are often obtained through the structured group estimation process of planning poker. To increase the accuracy of such estimates, we propose to annotate user stories with symbols that highlight risk and effort drivers and thus give all team members a better understanding of a project's challenges. In this paper, we report on the results of a study that examines the effect of using risk and effort annotations on project teams' level of shared understanding, estimation accuracy and estimation bias. Our results show that the use of annotations in planning poker increases estimation accuracy.
Combining single-image and multiview super-resolution for mixed-resolution image plus depth data

In mixed-resolution multiview setups, a scene is captured from various viewpoints with cameras having different spatial resolutions. Compared to full-resolution systems, mixed-resolution setups allow for savings with respect to data transmission, storage, and costs. However, for applications like free viewpoint television, high-quality images are required for all available camera perspectives. Therefore, high-resolution cameras can be used to increase the image quality of a neighboring low-resolution view. Due to occlusions, some parts of the scene are invisible in the high-resolution reference views and thus cannot be directly synthesized from the neighboring perspectives. In this paper, we propose to integrate the idea of single-image super-resolution to better handle occluded areas and thus to improve the super-resolution quality for mixed-resolution multiview images. For a downsampling factor of 4, the proposed method achieves an average gain of 0.53 dB with respect to a comparable multiview super-resolution approach.
Reconstruction of multiview images taken with non-regular sampling sensors

Increasing spatial image resolution is a widely discussed area in the field of image processing. In this paper, we present an efficient reconstruction approach for high-resolution images, taken with irregularly shielded low-resolution sensors in a multiview setup. The approach is based on the sparsity assumption, meaning that natural images can be efficiently represented in a transform-domain using only few coefficients. Utilizing information from adjacent cameras results in a better reconstruction quality for the central high-resolution view. Since neighboring camera perspectives might differ in illumination, the information from adjacent views has to be adapted to the view to be reconstructed. The simulation results show that a proper incorporation of information from neighboring views leads to a PSNR gain of up to 2.20 dB compared to a state-of-the-art singleview reconstruction approach.
Two-Stage Process Modeling for Simulation in BPR

This work presents an approach to give business analysts access to the simulation of complex process environments by hiding the complexity and expressive power of Petri nets behind a subset of UML2 activity diagrams. To avoid the complexity to simply shift from the Petri nets into the activity diagrams we introduce a two-stage-scheme for the development of executable Petri net process models: Domain experts develop reusable Petri nets based domain models in the first stage while business analysts develop UML activity diagram based process models that reuse the domain models. The activity diagram process models are transformed into executable Petri nets based process models by utilizing the domain models for process composition. The article describes the conceptual method of the integration of both model types.
On Remote and Virtual Experiments in eLearning in Statistical Mechanics and Thermodynamics

The science of physics is based on theories and models as well as experiments: the former structure relations and simplify reality to a degree such that predictions on physical phenomena can be derived by means of mathematics. The latter allow verification or falsification of these predictions. Computer sciences allow a new access to this relationship, especially well-suited for education: new technologies provide simulations for the model, virtual instruments for running and evaluating real experiments and mathematical toolkits to solve equations derived from the theory analytically and to compare the outcome of all three methods. We will demonstrate this approach on two examples: ferromagnetism and thermodynamics
Distributed generation of a 400-Gb/s Nyquist 16QAM dense superchannel by fiber-frequency conversion

We generate an ultra-dense 400-Gb/s superchannel by combining four spatially distributed 28-GBd-Nyquist-16QAM-sub-carrier transmitters using optical processing in nonlinear fibers. The multiplexed sub-carriers are precisely frequency-allocated with guard bands down to 0% and achieve bit-error ratios below 3.8×10-3.
On the mDCT-PSNR image quality index

Full reference image quality indices assign a quality index to a pair of an undistorted reference image and a distorted image to be assessed; the quality of the index itself is then defined by its ability to predict the outcome of subjective tests performed by human observers judging the quality of the same image pair. In this article, a new DCT based image quality index is introduced whose complexity is between that of algorithms like SSIM and complex, HVS-based algorithms like VDP. Detailed experiments on the LIVE database show that the proposed algorithm performs best close to or below the visual threshold, and outperforms there existing algorithms like SSIM or VDP requiring only a mediocre complexity.
ViPLab - A Virtual Programming Laboratory for Mathematics and Engineering

In the process of the implementation of the eBologna program of the European states and the recent change of the German university system from the Diploma to the Bachelor/Master system, studies at German universities have been redesigned, courses have been condensed and learning content has been re-structured into granular "modules", each of which requires an evaluation at the end of the semester. Simultaneously, the skills required for working as an engineer changed as well, handling of computer software, knowledge of mathematical or numerical algorithms and programming skills play an increasingly important role in the daily job routine of the working engineer. To support the learning by practical exercises, engineering faculties, mathematics and physics, and the Computing Center of the University of Stuttgart setup a project for implementing an online programming lab for teaching the required skills. The focus of this project is to provide easy access to the necessary software tools, avoid the overhead of installation and maintenance, and seamlessly integrate these tools into the eLearning infrastructure of the university. This paper describes the motivation and backgrounds, the software infrastructure and early results of this project.
Parallel interleaving on parallel DSP architectures

Today's communications systems especially in the field of wireless communications rely on many different algorithms to provide applications with constantly increasing data rates and higher quality. This development combined with the wireless channel characteristics as well as the invention of turbo codes has particularly increased the importance of interleaver algorithms. In this paper we demonstrate the feasibility to exploit the hardware parallelism in order to accelerate the interleaving procedure. Based on a heuristic algorithm the possible speedup for different interleavers as a function of the degree of parallelism of the hardware is presented. The parallelization is generic in the sense that the assumed underlying hardware is based on a parallel datapath DSP architecture and therefore provides the flexibility of software solutions.
Parametric Amplification and Wavelength Conversion of Single- and Dual-Polarization DQPSK Signals

We demonstrate system experiments for polarization-independent parametric amplification and wavelength conversion of single-channel differential quadrature phase-shift keying (DQPSK) signals up to 112 Gbit/s. Dual-pump four-wave mixing in a highly nonlinear fiber is utilized to achieve up to 20 dB ON-OFF gain and conversion efficiency. The investigations are done in a polarization-dependent (straight) as well as in a polarization-independent (loop) configuration using single- and dual-polarization DQPSK. Particular attention is paid to the resulting optical signal-to-noise ratio penalties after the amplification. We ascribe this to pump-induced nonlinear phase noise. It is shown that this type of excess noise is increased for the loop configuration in comparison with the straight configuration due to Rayleigh backscattering and that it depends on the input polarization of the signal. Still, the penalty can be made negligible using high-quality pump sources.
PPLN-Waveguide Based Tunable Wavelength Conversion of QAM Data Within the C-Band

Tunable optical wavelength conversion of a 40 Gb/s 16-ary quadrature amplitude modulated signal within the C-band is demonstrated by cascaded sum frequency generation and difference frequency generation in a periodically-poled lithium niobate module. System experiments with conversion efficiencies of ~ 7.5 dB (excluding module loss) are presented. Bit-error ratio measurements confirm excellent conversion performance.
Fast and Context-Free Lossless Image Compression Algorithm Based on JPEG-LS

While the context-based entropy coding and bias cancellation steps in the JPEG-LS standard are key features to its compression performance, these steps also enlarge the memory footprint, create dependencies in the data path of implementations and hence limit parallelism in modern multi-core or GPU architectures, and the throughput in hardware implementations. In the proposed modification of JPEG-LS, such most expensive parts with respect to memory space requirements and computational complexity are omitted.
Multiview super-resolution using high-frequency synthesis in case of low-framerate depth information

Increasing the image sharpness of low-resolution views is a key issue in the multiview image and video processing domain. Thereby, a low-resolution view gets refined by high-frequency content that can either be obtained from temporally or spatially adjacent highresolution reference images. We propose a refined super-resolution algorithm for multiview images that is robust to the usage of temporally highly misaligned depth maps. The temporal misalignment may be caused either by a temporal subsampling or a lower framerate of the depth camera with respect to the image cameras. Our refinement step is based on a blockwise low-frequency registration in order to efficiently adapt the high-frequency content of the highresolution reference to the low-resolution destination view. The simulation results show that our proposed algorithm leads to a peak PSNR gain of up to 1.21 dB with respect to a comparable unrefined super-resolution approach. On average, our approach outperforms the unrefined super-resolution algorithm by 0.61 dB. For all considered scenarios the improvement of visual quality is also convincingly.
Universal Refinable Trellis Coded Quantization

We introduce a novel universal refinable trellis quantization scheme (URTCQ) that is suitable for bitplane coding with many reconstruction stages. Existing refinable trellis quantizers either require excessive codebook training and are outperformed by scalar quantization for more than two stages (MS-TCQ, E-TCQ), require a huge computational burden (SR-TCQ) or achieve a good rate distortion performance in the last stage only (UTCQ). The presented quantization technique is a mixture of a scalar quantizer and an improved version of the E-TCQ. For all supported sources only one time training to an i.i.d. uniform source is required and its incremental bitrate is not more than 1 bps for each stage. The complexity is proportional to the number of stages and the number of trellis states. We compare the rate distortion performance of our work on generalized Gaussian i.i.d. sources with the quantizers deployed in JPEG2000 (USDZQ, UTCQ). It turns out that it is in no stage worse than the scalar quantizer and usually outperforms the UTCQ except for the last stage.
Networking Resources for Research and Scientific Education in BW-eLabs

The aim of the BW-eLabs architecture (networked virtual and remote labs in Baden-Württemberg) is the expansion of the access to heterogeneous experimental resources (remote and virtual) for the sustainable indexing and use of raw data and experiments for research and education purposes. The creation of efficient possibilities of external access to local experimental surroundings as well as a guarantee of transparency and reproducibility of experiments form a central request. A substantial characteristic of BW-eLabs is that the corresponding data and documents are examined along their entire life cycle and embedded into the entire process chain of experimental environments. Scientific communities and the promotion of cooperation and collaboration in high-technology take centre stage in this concept. Nanotechnology serves as a pilot discipline because especially in this cost intensive area access to experimental equipment is an important prerequisite for ensuring access to professional tools for all scientific communities involved. Existing infrastructure, e.g. digital libraries, decentralized tools, and repositories, are embedded into the 3D-Plattform BW-eLabs. The BW-eLabs stands under OpenAccess-Policy and sees itself as an open network for scientific data and experimental set-ups.
Feasibility study of SOA-preamplified coherent reception for 112 Gb/s DP-QPSK unamplified link

The feasibility of preamplifying a 100G DP-QPSK signal before coherent reception is investigated. A sensitivity improvement of 3 dB is found. Theoretically, there is another 5 dB of margin, and it is believed that several dBs can be gained through SOA optimization.
Subjective quality assessment database of HDR images compressed with JPEG XT

Recent advances in high dynamic range (HDR) capturing and display technologies attracted a lot of interest to HDR imaging. Many issues that are considered as being resolved for conventional low dynamic range (LDR) images pose new challenges in HDR context. One such issue is a lack of standards for HDR image compression. Another is the limited availability of suitable image datasets that are suitable for studying and evaluation of HDR image compression. In this paper, we address this problem by creating a publicly available dataset of 20 HDR images and corresponding versions compressed at four different bit rates with three profiles of the upcoming JPEG XT standard for HDR image compression. The images cover different scenes, dynamic ranges, and acquisition methods (fusion from several exposures, frame of an HDR video, and CGI generated images). The dataset also includes Mean Opinion Scores (MOS) for each compressed version of the images obtained from extensive subjective experiments using SIM2 HDR monitor.
Deadzone Based Rate Allocation for JPEG XR

Similar to the JPEG image compression standard, the JPEG XR image compression solely controls the image quality loss and hence the output rate by means of the quantizer bucket sizes, a precise rate control mechanism like the EBCOT rate allocation algorithm in JPEG 2000 is not specified, and hence rate-distortion optimality of the quantizer is, in general, not given. In this work, a simple rate-control mechanism for JPEG XR is introduced that allows an efficient control of the quantizer towards rate-distortion optimality. One possibility to implement this quantizer control would be to use the spatial variable quantization feature of JPEG XR, but it was seen in an earlier work that the additional side information required to transmit the quantization setting almost compensates the PSNR gain of variable quantization and complicates the rate allocation process by requiring an additional quantizer allocation step. However, while JPEG XR defines the image reconstruction process completely, an encoder still has the freedom to select the dead zone size of the quantizer, this mechanism has the additional advantage that no additional side information needs to be transmitted and that the dead zone size is not, unlike the quantizer bucket size, constrained to a set of pre-defined values specified in the standard. It is found that the image quality of JPEG XR can be improved by about 0.2 to 0.4 dB by performing a rate-distortion optimal selection of the dead zone, this gain is seen to be comparable to the PSNR loss of a JPEG 2000 codec where, for experimental reasons, EBCOT rate control has been turned off.