Vector Resolution Research Articles

Compression Algorithm Analysis of In-Situ (S)TEM Video: Towards Automatic Event Detection and Characterization

Journal Article Compression Algorithm Analysis of In-Situ (S)TEM Video: Towards Automatic Event Detection and Characterization Get access Jeremy R Teuton, Jeremy R Teuton Fundamental and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA 99352, USA Search for other works by this author on: Oxford Academic Google Scholar Richard L Griswold, Richard L Griswold National Security Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA Search for other works by this author on: Oxford Academic Google Scholar B Layla Mehdi, B Layla Mehdi Fundamental and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA 99352, USA Search for other works by this author on: Oxford Academic Google Scholar Nigel D.Browning Nigel D.Browning Fundamental and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA 99352, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 2329–2330, https://doi.org/10.1017/S1431927615012428 Published: 23 September 2015

A fine-grain distortion and complexity aware parameter tuning model for the H.264/AVC encoder

Most existing video encoders currently used in mobile applications are unable to gracefully degrade their output quality as the battery life nears its end. In other words, they cannot manage power consumption to efficiently utilize the available power resources. To be able to effectively adapt to changes in the encoder′s software and hardware platforms, especially due to the power limitations of mobile devices, the effect of encoder parameters on the encoding quality and power consumption has to be represented using a Rate–Distortion–Complexity (R–D–C) model. Most existing R–D–C models only consider macroblock level parameters, and overlook other higher level parameters that may have a more significant impact on complexity. In this paper, the distortion and complexity of the H.264/AVC encoder is controlled considering a subset of higher level encoding parameters consisting of search range, number of reference frames, and motion vector resolution. First, the complexity of full and fast motion estimation methods is modeled in an implementation and platform independent manner. Then, using this complexity model, a common encoding parameter setting table is derived, which leads to the least amount of distortion for each complexity condition. Finally, a complexity control mechanism is proposed which tunes the encoding parameters in a real-time manner. The proposed model can be combined with other existing macroblock level models in order to design a two-phase fine grain complexity controller. Simulation results indicate that when our method is integrated with the direct resource allocation (DRA) approach, performance increases by an average of 1.02dB and 1.06dB for full and fast motion estimation approaches, respectively.

HEVC에서의 적응적 움직임 벡터 해상도를 이용한 움직임 추정 및 부호화 기법

In this papar, we propose a new motion estimation and coding technique using adaptive motion vector resolution. Currently, HEVC encodes a video using 1/4 motion vector resolution. If there are high texture regions in a picture, HEVC can't get a performance enough. So, we insert additional 1-bit flag meaning whether motion vector resolution is 1/4 or 1/8 in PU syntax. Therefore, decoder can recognize the transmitted motion vector resolution. Experimental results show that maximum coding efficiency gain of the proposed method is up to 5.3% in luminance and 7.9% in chrominance. Average computional time complexity is increased about 33% in encoder and up to 5% in decoder.

적응적인 움직임 벡터 해상도를 이용한 움직임 벡터 부호화 방법

MPEG-2, MPEG-4와 같은 기존의 비디오 코덱에서는 인터 예측을 수행할 때 고정된 해상도의 움직임 벡터를 사용한다. 그러나 KTA 참조 소프트웨어에서는 움직임 벡터의 해상도를 슬라이스 단위로 선택하여 사용할 수 있는 기능을 지원한다. 그러나 선택된 하나의 움직임 벡터 해상도를 슬라이스 전체에 일괄적으로 적용하기 때문에 영상의 국지적인 특성을 반영하는데 어려움이 있다. 본 논문에서는 탐색 구간에 따라 적응적으로 움직임 벡터의 해상도를 결정하는 방법을 제안한다. 움직임 벡터의 탐색 영역을 움직임 벡터가 예측 움직임 벡터로부터 떨어진 거리에 따라 다수개의 구간으로 분할하고, 각 구간에 대하여 하나의 움직임 벡터 해상도를 할당하여 움직임 예측에 적용한다. 따라서 제안하는 방법의 부호화 효율은 각 구간을 분할하는 Threshold와 움직임 벡터를 부호화하는 엔트로피 코딩 방법에 영향을 받는다. HEVC의 참조 소프트웨어인 HM3.0을 이용하여 실험한 결과, Random Access 부호화 구조에서는 평균적으로 약 0.9%의 성능 향상을 얻을 수 있었으며, Low Delay 부호화 구조에 B picture를 적용한 경우는 약 0.6%, P picture를 적용한 경우에서는 약 2.7%의 평균 발생 비트량 감소를 확인할 수 있었다. In most conventional video codecs, such as MPEG-2 and MPEG-4, inter coding is performed with the fixed motion vector resolution. When KTA software was developed, resolution for MVs can be selected in each slice. Although KTA codec uses a variety of resolutions for ME, the selected resolution is applied over the entire pixels in the slice and the statistical property of the local area is not considered. In this paper, we propose an adaptive decision scheme for motion vector resolution which depends on region, where MV search area is divided to multiple regions according to the distance from PMV. In each region, the assigned resolution is used to estimate MV. Each region supports different resolution for ME from other regions. The efficiency of the proposed scheme is affected from threshold values to divide the search area and the entropy coding method to encode the estimated MV. Simulation results with HM3.0 which is the reference software of HEVC show that the proposed scheme provides bit rate gains of 0.9%, 0.6%, and 2.9% in Random Access, Low Delay with B picture, and Low Delay with P picture structures, respectively.

Witsenhausen–Wyner Video Coding

Inspired by Witsenhausen and Wyner's 1980 (now expired) patent on “interframe coder for video signals,” this paper presents a Witsenhausen-Wyner video codec, where the motion-compensated previously decoded video frame is used at the decoder as side information for joint decoding. Specifically, we replace predictive Inter coding in H.264/AVC by the syndrome-based coding scheme of Witsenhausen and Wyner, while keeping the Intra and Skip modes of H.264/AVC unchanged. We employ forward motion estimation at the encoder and send the motion vectors to help generate side information at the decoder, since our focus is not on low-complexity encoding. We also examine the tradeoff between the motion vector resolution and coding efficiency. Within the Witsenhausen-Wyner coding mode, we optimize the decision between syndrome coding and entropy coding among different discrete cosine transform (DCT) bands and among different bit-planes within each DCT coefficient. Extensive simulations of video transmission over wireless networks show that Witsenhausen-Wyner video coding is more robust against channel errors than H.264/AVC. The price paid for enhanced error-resilience with Witsenhausen-Wyner coding is a small loss in compression efficiency.

Video Coding Using a Simplified Block Structure and Advanced Coding Techniques

This paper describes a new video coding scheme based on a simplified block structure that significantly outperforms the coding efficiency of the ISO/IEC 14496-10 ITU-T H.264 advanced video coding (AVC) standard. Its conceptual design is similar to a typical block-based hybrid coder applying prediction and subsequent prediction error coding. The basic coding unit is an 8 × 8 block for inter, and an 8 × 8 or a 16 × 16 block for intra, instead of the usual 16 × 16 macroblock. No larger block sizes are considered for prediction and transform. Based on this simplified block structure, the coding scheme uses simple and fundamental coding tools with optimized encoding algorithms. In particular, the motion representation is based on a minimum partitioning with blocks sharing motion borders. In addition, compared to AVC, the new and improved coding techniques include: block-based intensity compensation, motion vector competition, adaptive motion vector resolution, adaptive interpolation filters, edge-based intra prediction and enhanced chrominance prediction, intra template matching, larger trans forms and adaptive switchable transforms selection for intra and inter blocks, and nonlinear and frame-adaptive de-noising loop filters. Finally, the entropy coder uses a generic flexible zero tree representation applied to both motion and texture data. Attention has also been given to algorithm designs that facilitate parallelization. Compared to AVC, the new coding scheme offers clear benefits in terms of subjective video quality at the same bit rate. Objective quality improvements are equally significant. At the same quality, an average bit-rate reduction of 31% compared to AVC is reported.

A Hybrid Video Coder Based on Extended Macroblock Sizes, Improved Interpolation, and Flexible Motion Representation

This paper describes a video coding technology proposal submitted by Qualcomm in response to a joint call for proposals (CfP) issued by ITU-T SG16 Q.6 (VCEG) and ISO/IEC JTC1/SC29/WG11 (MPEG) in January 2010. The proposed video codec follows a hybrid coding approach based on temporal prediction, followed by transform, quantization, and entropy coding of the residual. Some of its key features are extended block sizes (up to 64 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex></formula> 64), single pass switched interpolation filters with offsets, mode-dependent directional transforms for intra-coding, luma and chroma high precision filtering, geometric motion partitions, adaptive motion vector resolution and efficient 16-point transforms. It also incorporates internal bit-depth increase and modified quadtree-based adaptive loop filtering. Simulation results are presented to demonstrate the high compression efficiency achieved by the proposed video codec at the expense of moderate increase in encoding and decoding complexity compared to the advanced video coding standard (AVC/H.264). For the random access and low delay configurations, it achieved average bit rate reductions of 30.9% and 33.0% for equivalent peak signal-to-noise ratio, respectively, compared to the corresponding AVC anchors. The proposed codec scored highly in both subjective evaluations and objective metrics and was among the best-performing CfP proposals.

A-priori testing of an eddy viscosity model for the density-weighted subgrid scale stress tensor in turbulent premixed flames

In this study, we report on the direct measurement of the density-weighted subgrid scale (SGS) stress tensor in turbulent premixed flames. In large-eddy simulations (LES), this unresolved tensor is typically modelled using eddy viscosity approaches. Additionally to the direct measurement, we provide a pure experimentally based a-priori test of the commonly used eddy viscosity model suggested by Smagorinsky. For two turbulent premixed V-shaped methane–air flames, a statistical analysis is presented where the correlation between the directly measured SGS stress tensor and the eddy viscosity model following Smagorinsky is tested. The measurement strategy is based on the application of a dual-plane stereo-PIV technique which enables the measurement of the 3D flow field in two parallel planes. This allows the determination of velocities as well as velocity gradients in all three directions. Here, a vector resolution of 118 μm was achieved. For a priori testing, the data are subjected to a spatial filtering procedure that reproduces the application of the filter function in LES. The calculation of velocity gradients is performed after the application of this spatial averaging. Additionally to the velocity field, the flame front position is deduced from the clearly observable step in the tracer particle number density between burnt and unburnt regions of the flame. This facilitates the direct single-shot-based evaluation of all components of the density-weighted SGS stress tensor. Additionally, the model expressions related to these terms can be determined, which is done in this first study for the static Smagorinsky model. With that, the instantaneous local comparison between directly measured stress terms and modelled terms is possible, based on the instantaneous local evaluation procedure. The measurement procedure is described, and first results are presented and discussed. They show a rather poor performance of the static form of the Smagorinsky model (with fixed Smagorinsky constant). Our future aims are to use the directly measured SGS data for the a-priori comparison with more advanced models.

Measurement techniques predicting the effectiveness of an oral appliance for obstructive sleep apnea hypopnea syndrome.

The purpose of this study is to determine the measurement techniques that can predict the effectiveness of an oral appliance (OA) for the treatment of patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Split-night polysomnography and esophageal pressure (Pes) were recorded, and cephalometric tracings were superimposed for 25 OSAHS patients. The patients were classified into good and poor responders according to their apnea hypopnea index (AHI) and mean nadir Pes. When the degree of anterior displacement of the mandible was expressed by vector resolution, it was significantly different between the good and poor responders, whereas there was no significant difference in downward and total mandibular displacement between the two groups. Among the good responders evaluated on the basis of mean nadir Pes, their apnea index, hypopnea index, and mean nadir Pes were significantly different. However, AHI alone cannot predict the effectiveness of OA treatment. Good responders defined by mean nadir Pes also had short soft palates and a wide pharyngeal airway space. Conversely, no significant differences were observed in these parameters when good responders and poor responders are defined by AHI. Logistic regression analysis revealed that the degree of anterior displacement of the mandible showed a significant odds ratio of 1.97. In conclusion, evaluations based on Pes and analyses of the mandibular displacement expressed by vector resolution using a cephalometric superimposition technique can provide important clinical information in evaluation measurements and may be useful for the prediction of the efficacy of OA treatment for patients with OSAHS.

MC Hammer's Contribution to Physics

Column Editor's note: You never know what will be the “hook” that will capture the imagination of students and get them excited about learning. Wade Roberts, who has been the physics teacher at Centennial High School in Franklin, TN, since 1998, shares a technique he uses to help students relate to the ideas being presented. Use your imagination to envision the fun his students seem to have as they learn about vector resolution.

Development of Multiorgan Finite Element-Based Prostate Deformation Model Enabling Registration of Endorectal Coil Magnetic Resonance Imaging for Radiotherapy Planning

Endorectal coil (ERC) magnetic resonance imaging (MRI) provides superior visualization of the prostate compared with computed tomography at the expense of deformation. This study aimed to develop a multiorgan finite element deformable method, Morfeus, to accurately co-register these images for radiotherapy planning. Patients with prostate cancer underwent fiducial marker implantation and computed tomography simulation for radiotherapy planning. A series of axial MRI scans were acquired with and without an ERC. The prostate, bladder, rectum, and pubic bones were manually segmented and assigned linear elastic material properties. Morfeus mapped the surface of the bladder and rectum between two imaged states, calculating the deformation of the prostate through biomechanical properties. The accuracy of deformation was measured as fiducial marker error and residual surface deformation between the inferred and actual prostate. The deformation map was inverted to deform from 100 cm(3) to no coil. The data from 19 patients were analyzed. Significant prostate deformation occurred with the ERC (mean intrapatient range, 0.88 +/- 0.25 cm). The mean vector error in fiducial marker position (n = 57) was 0.22 +/- 0.09 cm, and the mean vector residual surface deformation (n = 19) was 0.15 +/- 0.06 cm for deformation from no coil to 100-cm(3) ERC, with an image vector resolution of 0.22 cm. Accurately deformed MRI scans improved soft-tissue resolution of the anatomy for radiotherapy planning. This method of multiorgan deformable registration enabled accurate co-registration of ERC-MRI scans with computed tomography treatment planning images. Superior structural detail was visible on ERC-MRI, which has potential for improving target delineation.

Determining the Effect of an Electromagnetic Window or Radome Wall Upon a Circularly Polarized Transmission

Based on the vector resolution of the orthogonal components of a circularly polarized signal, and the known perpendicular and parallel transmission coefficients of a dielectric radome panel or EM window, a method is presented using a standard computer spreadsheet to predict both the circularly polarized attenuation (CPA) and the cross-polarization-ratio (XPR) performance of the panel

Quasi-optical Gaussian beam tracing to evaluate Doppler backscattering conditions

Microwave beam backscattering near the cut-off layer appears to be the most interesting diagnostic to observe density fluctuation time evolution for a given localization in the plasma and at a defined wave vector. It also provides perpendicular plasma velocity. Scattering only occurs when the Bragg selection rule is fulfilled, i.e. when the scattering wave vector is almost perpendicular to the magnetic field. In order to evaluate these scattering conditions, ray tracing is required. 3D geometry is necessary to evaluate the angle between the magnetic field and the wave vector at the reflection. The ripple effect on the iso-index layer curve cannot be neglected. Scattering localization and wave vector resolution can be approached if single ray tracing is replaced with quasi-optical beam tracing. Optical propagation is still considered in the WKB approximation but the beam is described as multiple connected rays. The beam radial expansion due to diffraction is well described. This approach allows one to compute beam parameters for all data acquisitions (50 triggers per shot) and all shots (40 shots per day) during the following night on a recent personal computer with MatLab©.

Adaptive interpolation filters and high-resolution displacements for video coding

Standardized hybrid video coding systems are based on motion compensated prediction with fractional-pel displacement vector resolution. In the recent video coding standard H.264/AVC, a displacement vector resolution of 1/4-pel is applied. In order to estimate and compensate these fractional-pel displacements, interpolation filters are used. So far, these interpolation filters are invariant. The same filter with the same filter-coefficients is applied for all sequences and for all images of a sequence. Therefore, it is not possible to consider nonstationary statistical properties of the video signal and the motion compensated prediction process like aliasing, quantization errors, and displacement estimation errors. This paper presents two techniques that improve the motion compensated prediction and accordingly the coding efficiency. The first technique applies an adaptive interpolation filter that uses filter-coefficients which are adapted once per image. The adapted filter-coefficients are coded and transmitted. The second technique is based on an increased displacement vector resolution of 1/8-pel. In combination, the developed techniques indicate bit-rate reductions up to 25 % compared to H.264/AVC.

Trilinear evolving factor analysis for the resolution of three-way multi-component chromatograms

In the resolution of overlapping chromatographic peaks, reliable information about the concentration windows of all chemical components is crucial for the success of many multivariate resolution methods. In this paper, taking the advantage of trilinearity that is intrinsic in many three-way data arrays, the trilinear evolving factor analysis (TEFA) is derived to establish a trilinear rank map for three-way multi-component chromatograms. With the information of local rank obtained from the trilinear rank map, selective region of each component can be determined. This provides the possibility to resolve the profiles of a single component one by one. It is shown that combining the local eluting information and the coupled vector resolution, a fast and reliable non-iterative resolution of the trilinear data array can be obtained. Simulated and real experimental results have demonstrated that the proposed method possesses the properties of easy implementation and excellent performance for the resolution of three-way multi-component chromatograms.

KWS-3, the new focusing-mirror ultra small-angle neutron scattering instrument and reflectometer at Jülich

In Jülich, a new high-resolution small-angle neutron scattering (SANS) instrument and reflectometer has been built. The principle of this instrument is a one-to-one image of an entrance aperture on a 2D position-sensitive detector by neutron reflection on a double-focusing toroidal mirror. It permits to perform SANS studies with a scattering wave vector resolution between 10 −3 and 10 −4 A ̊ −1 with considerable intensity advantages over pinhole-SANS instruments. To date, KWS-3 is the worldwide unique SANS instrument running on this principle. We present here the characterization of the image produced by the mirror and a measurement of the scattering from a diffraction grating.

Improving the coherence of a low-energy electron beam by modulation

In a standard low-energy electron generator the beam is formed by particles traveling close to the axis of symmetry. However some electron trajectories are unstable and strongly dependent on the initial conditions. Numerical ray tracing shows that ultimate beam coherence is limited by these trajectories that pass far from the symmetry axis. This contribution can be partly eliminated by modulating the initial conditions and selecting the modulated response. This is exemplified with a low-energy electron beam used for electron diffraction, where the beam current modulation produces a modulated diffraction pattern that displays noteworthy improvement (sevenfold) in wave vector resolution.

Motion- and aliasing-compensated prediction for hybrid video coding

In order to reduce the bit rate of video signals, the standardized coding techniques apply motion-compensated prediction in combination with transform coding of the prediction error. By mathematical analysis, it is shown that aliasing components are deteriorating the prediction efficiency. In order to compensate the aliasing, two-dimensional (2-D) and three-dimensional interpolation filters are developed. As a result, motion- and aliasing-compensated prediction with 1/4-pel displacement vector resolution and a separable 2-D Wiener interpolation filter provide a coding gain of up to 2 dB when compared to 1/2-pel displacement vector resolution as it is used in H.263 or MPEG-2. An additional coding gain of 1 dB can be obtained with 1/8-pel displacement vector resolution when compared to 1/4-pel displacement vector resolution. In consequence of the significantly improved coding efficiency, a Wiener interpolation filter and 1/4-pel displacement vector resolution is applied in H.264/AVC and in MPEG-4 (advanced simple profile).

An Algorithm for Three-way Data Analysis That Alternatively Minimizes Coupled Vector (COV) Resolution Error and PARAFAC Error

A novel algorithm, alternatively minimizing coupled vector (COV) resolution error and PARAFAC error algorithm, is proposed in this paper. This algorithm can overcome the problem of slow convergence and is insensitive to the estimation of component number, such problems are unavoidable while using the traditional parallel factors analysis (PARAFAC) algorithm. In other words, this algorithm is capable of improving the computing speed and providing accurate resolutions provided that the number of factors used in the computation is no less than that of the actual underlying ones. The characteristic performances were demonstrated with a novel fluorescence data array.

Synchrotron radiation study of neptunium phosphide

NpP orders at ${T}_{N}\ensuremath{\sim}120\mathrm{K}$ into an incommensurate longitudinal antiferromagnetic structure and becomes commensurate with $\mathbf{k}=〈\frac{1}{3}00〉$ at ${T}_{\mathrm{com}}=70\mathrm{K}$ with a first-order phase transition. We have examined the magnetic phase diagram with resonant x-ray magnetic scattering (RXMS) on a single crystal of NpP with the photon energy tuned to the Np ${M}_{4}$ edge at 3.846 keV. A number of phases are present just above ${T}_{\mathrm{com}}$ but in the lower 3+, 3- phase a single peak is observed, together with a tetragonal distortion. Our study is in agreement with earlier neutron work, but the increased wave vector resolution with RXMS gives more details. A satellite at $2k$ was observed below ${T}_{\mathrm{com}}$ in the unrotated $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\sigma}}\ensuremath{\sigma}$ polarization channel with a strong dependence on the incident photon energy. A model for this is proposed by considering small differences in the charge distribution around the two independent Np sites in the commensurate 3+, 3- phase, and is consistent with the observation by M\"ossbauer spectroscopy of two different electric quadrupole moments in this temperature range. However, to determine the origin of this signal its intensity as a function of the azimuthal angle must be determined.