nils-herrmann/clean_scirepeval huggingface dataset:
Modeling and Analyzing Multi-agent Task Plans for Intelligent Virtual Training System using Petri Nets

Integrated virtual reality with intelligent tutoring system, a multi-agent architecture was proposed for intelligent virtual training system (IVTS) for mine safety training. In order to make sure IVTS agent's task plans reliable and adaptive, a Petri nets-based declarative method was applied to model the virtual training task planning knowledge, which was represented as task planning knowledge Petri nets (TP-PNets), and an algorithm was implemented to construct TP-PNets. Then, hierarchy colored Petri nets (HCPN) was used to model multi-agent task planning behaviors for IVTS, and simulation and message sequence chart was used to analyze and verify the agent task planning HCPN model
Synthesis of LiMnO 2 porous microsphere and its electrochemical behaviour as cathode material in lithium-ion batteries

Orthorhombic LiMnO 2 porous microspheres with the pore size of 200-500 nm were synthesised by Mn 2 O 3 precursor and LiOH·H 2 O at 750°C for 5 h. Field-emitting scanning electron microscope images show the obtained products basically preserve the initial morphology of Mn 2 O 3 precursor. The electrochemical tests of the as-obtained LiMnO 2 presented the maximum discharge capacity of 163 mAh/g at the 11th cycle, and remained above 143 mAh/g after 30 cycles at a current density of 30 mA/g, corresponding to a capacity fading of 12.1%. For comparative purpose, the LiMnO 2 nanoparticles prepared with the Li 2 CO 3 substituted for LiOH·H 2 O as the lithium source were studied, which showed their maximum discharge capacity was only 153 mAh/g, together with a capacity of 136 mAh/g after 30 cycles at the same current density.
A monocular collision warning system

A system for the detection of independently moving objects by a moving observer by means of investigating optical flow fields is presented. The usability of the algorithm is shown by a collision detection application. Since the measurement of optical flow is a computationally expensive operation, it is necessary to restrict the number of flow measurements. The first part of the paper describes the usage of a particle filter for the determination of positions where optical flow is calculated. This approach results in a fixed number of optical flow calculations leading to a robust real time detection of independently moving objects on standard consumer PCs. The detection method for independent motion relies on knowledge about the camera motion. Even though inertial sensors provide information about the camera motion, the sensor data does not always satisfy the requirements of the proposed detection method. The second part of this paper therefore deals with the enhancement of the camera motion using image information. The third part of this work specifies the final decision module of the algorithm. It derives a decision (whether to issue a warning or not) from the sparse detection information.
Dynamic 3-D Scene Analysis Through Synthesis Feedback Control

The analysis of 3-D scenes consisting of nonrigid moving objects using 2-D image sequences is discussed. A parametric description of dynamic objects is extracted, and the time-variant scene parameters are estimated throughout the sequence by employing an analysis-by-synthesis approach. Images are synthesized from the parametric scene description and compared with the original images input to the camera. Frame differences between the synthesized and original images are evaluated to obtain an estimated scene parameter update. The analysis method is applied to videophone scenes in the form of a data compression algorithm, whereby the scene parameters are transmitted and the output sequence is synthesized at the receiver.
Real-time Adaptive Tone Mapping for Monitoring High Contrast Hemispherical Image Capture with the GPU

The exposure of high dynamic range scenes needs special attention to capture all details. A new method for a low dynamic monitoring preview of the local scene details is presented. We follow the idea of edge preserving nonlinear bilateral filtering instead of classic methods such as linear high pass filtering or histogram equalization. Real-time performance is achieved with a GPU implementation keeping the CPU free for other tasks.
Restoration of images with wavefront aberrations

This contribution deals with image restoration in optical systems with coherent illumination, which is an important topic in astronomy, coherent microscopy and radar imaging. Such optical systems suffer from wavefront distortions, which are caused by imperfect imaging components and conditions. Known image restoration algorithms work well for incoherent imaging, they fail in case of coherent images. In this paper a novel wavefront correction algorithm is presented, which allows image restoration under coherent conditions. In most coherent imaging systems, especially in astronomy, the wavefront deformation is known. Using this information, the proposed algorithm allows a high quality restoration even in case of severe wavefront distortions. We present two versions of this algorithm, which are an evolution of the Gerchberg-Saxton and the Hybrid-Input-Output algorithm. The algorithm is verified on simulated and real microscopic images.
Geometric Calibration of Head-Mounted Displays and its Effects on Distance Estimation

Head-mounted displays (HMDs) allow users to observe virtual environments (VEs) from an egocentric perspective. However, several experiments have provided evidence that egocentric distances are perceived as compressed in VEs relative to the real world. Recent experiments suggest that the virtual view frustum set for rendering the VE has an essential impact on the user's estimation of distances. In this article we analyze if distance estimation can be improved by calibrating the view frustum for a given HMD and user. Unfortunately, in an immersive virtual reality (VR) environment, a full per user calibration is not trivial and manual per user adjustment often leads to mini- or magnification of the scene. Therefore, we propose a novel per user calibration approach with optical see-through displays commonly used in augmented reality (AR). This calibration takes advantage of a geometric scheme based on 2D point - 3D line correspondences, which can be used intuitively by inexperienced users and requires less than a minute to complete. The required user interaction is based on taking aim at a distant target marker with a close marker, which ensures non-planar measurements covering a large area of the interaction space while also reducing the number of required measurements to five. We found the tendency that a calibrated view frustum reduced the average distance underestimation of users in an immersive VR environment, but even the correctly calibrated view frustum could not entirely compensate for the distance underestimation effects.
3D-TV LDV content generation with a hybrid ToF-multicamera RIG

In this paper we introduce an approach for automatic generation of Layered Depth Video (LDV) content for 3D television (3DTV) purposes. The proposed approach relies on a capturing system consisting of two time of flight cameras (ToF) and five color cameras. The LDV content is generated for the central color camera, based on the depth images provided by the ToF cameras and texture information provided by the color cameras. Through different viewpoints of the ToF cameras and color cameras, we are able to reconstruct depth and texture information not only for foreground objects, but also in the occluded areas. The estimated information is then combined to one consistent LDV representation.
An Adaptable Robot Vision System Performing Manipulation Actions With Flexible Objects

This paper describes an adaptable system which is able to perform manipulation operations (such as Peg-in-Hole or Laying-Down actions) with flexible objects. As such objects easily change their shape significantly during the execution of an action, traditional strategies, e.g, for solve path-planning problems, are often not applicable. It is therefore required to integrate visual tracking and shape reconstruction with a physical modeling of the materials and their deformations as well as action learning techniques. All these different submodules have been integrated into a demonstration platform, operating in real-time. Simulations have been used to bootstrap the learning of optimal actions, which are subsequently improved through real-world executions. To achieve reproducible results, we demonstrate this for casted silicone test objects of regular shape. Note to Practitioners - The aim of this work was to facilitate the setup of robot-based automation of delicate handling of flexible objects consisting of a uniform material. As examples, we have considered how to optimally maneuver flexible objects through a hole without colliding and how to place flexible objects on a flat surface with minimal introduction of internal stresses in the object. Given the material properties of the object, we have demonstrated in these two applications how the system can be programmed with minimal requirements of human intervention. Rather than being an integrated system with the drawbacks in terms of lacking flexibility, our system should be viewed as a library of new technologies that have been proven to work in close to industrial conditions. As a rather basic, but necessary part, we provide a technology for determining the shape of the object when passing on, e.g., a conveyor belt prior to being handled. The main technologies applicable for the manipulated objects are: A method for real-time tracking of the flexible objects during manipulation, a method for model-based offline prediction of the static deformation of grasped, flexible objects and, finally, a method for optimizing specific tasks based on both simulated and real-world executions.
3-D surface reconstruction from stereoscopic image sequences

A stereoscopic scene analysis system for 3-D modeling of objects from stereoscopic image sequences is described. A dense map of 3-D surface points is obtained by image correspondence, object segmentation, interpolation, and triangulation. Emphasis is put on the accurate measurement of image correspondences from grey level images. The surface geometry of each scene object is approximated by a triangular wire-frame which stores the surface texture in texture maps. Sequence processing serves to track camera motion and to fuse surfaces from different view points into a consistent 3-D surface model. From the textured 3-D models, highly realistic image sequences from arbitrary view points can be synthesized using computer graphics techniques.<<ETX>>
An airborne Bayesian color tracking system

Mobile tracking systems are of wide interest. For instance sport photographers often hire helicopters to obtain close range images of e.g. aquatic athletes. Besides the high price for hiring a helicopter, good helicopter pilots are not everywhere available. One way to circumvent these problems is the use of a cheap model helicopter. Since flying a model helicopter is a demanding task, there are either two persons needed for the operation of the system (one person for steering the helicopter and the other for the operation of the camera), or alternatively an automatic tracking system can be used. In this work an automatic, image based tracking system is described. The algorithm combines color histograms as similarity measures with a particle filter and achieves fast and robust tracking results. A novel method for fast histogram computation is proposed. The system keeps the object of interest automatically in the viewing field of the camera so that the only task left to the camera operator is to initiate the imaging process. This simple task can be additionally managed by the helicopter pilot so that a single person is sufficient to steer the helicopter and to take the images.
Pose Estimation from Line Correspondences: A Complete Analysis and a Series of Solutions

In this paper we deal with the camera pose estimation problem from a set of 2D/3D line correspondences, which is also known as PnL (Perspective-n-Line) problem. We carry out our study by comparing PnL with the well-studied PnP (Perspective-n-Point) problem, and our contributions are three-fold: (1) We provide a complete 3D configuration analysis for P3L, which includes the well-known P3P problem as well as several existing analyses as special cases. (2) By exploring the similarity between PnL and PnP, we propose a new subset-based PnL approach as well as a series of linear-formulation-based PnL approaches inspired by their PnP counterparts. (3) The proposed linear-formulation-based methods can be easily extended to deal with the line and point features simultaneously.
Perspectively Invariant Normal Features

We extend the successful 2D robust feature concept into the third dimension in that we produce a descriptor for a reconstructed 3D surface region. The descriptor is perspectively invariant if the region can locally be approximated well by a plane. We exploit depth and texture information, which is nowadays available in real-time from video of moving cameras, from stereo systems or PMD cameras (photonic mixer devices). By computing a normal view onto the surface we still keep the descriptiveness of similarity invariant features like SIFT while achieving in- variance against perspective distortions, while descriptiveness typically suffers when using affine invariant features. Our approach can be exploited for structure-from-motion, for stereo or PMD cameras, alignment of large scale reconstructions or improved video registration.
Hand-Held Monocular SLAM Based on Line Segments

This paper presents an approach of visual SLAM using line segments as primitives. We choose Plucker lines to represent spatial lines and derive a novel fast line projection function based on the relationship between Pl̈ucker line and Plucker matrix. During normal SLAM procedure, the Near by Line Tracking (NLT) method is adopted to track lines and an Extended Kalman Filter (EKF) is used to predict and update the state of the camera and line landmarks. After each update step, a robust spatial line reconstruction algorithm is used to find new line landmarks and to add them into the map. The SLAM procedure is under supervision and when failure is detected, a recovery method based on the angle histogram of key frames is adopted to relocalize the camera and re-start the SLAM procedure. We demonstrate that our monocular SLAM system is robust to illumination change, partial occlusion and fast camera motion.
Fast projector-camera calibration for interactive projection mapping

We propose a fast calibration method for projector-camera pairs which does not require any special calibration objects or initial estimates of the calibration parameters. Our method is based on a structured light approach to establish correspondences between the camera and the projector view. Using the vanishing points in the camera and the projector view the internal as well as the external calibration parameters are estimated. In addition, we propose an interactive projection mapping scheme which allows the user to directly place two-dimensional media elements in the tangent planes of the target surface without any manual perspective corrections.
Increasing Realism and Supporting Content Planning for Dynamic Scenes in a Mixed Reality System incorporating a Time-of-Flight Camera

Mixed reality is the combination of real and virtual scene content. Besides correct alignment of the two modalities and correct occlusion handling the core issues to be tackled are the degree of realism and the ease of use. For a convincing perception correct occlusion handling and shadowing is mandatory. We present a system for mixed reality applications which features enhanced realism through automatic shadow computation and supported placement functions for virtual content. The system relies on the incorporation of a ToF-camera device. This device delivers real-time depth maps of the environment and is used to build a static environment model. It also allows correct handling of mutual occlusion between real and virtual content, shadow computation and enhanced content planning. Other mixed reality systems require expensive studio setups with complex camera tracking installations. Often multi- camera approaches in combination with chroma-keying facilities are used. The presented system is rather inexpensive, compact, mobile, flexible and provides convenient calibration procedures. The standard chroma-keying procedure is replaced by the usage of the environment model. The planning and alignment of virtual content is simplified by automatic extraction of dynamic content in the scene. This is essential for the placement of virtual content. With the presented system appropriate depth maps of the mixed content are available in real-time, which makes the approach suitable for 3DTV productions. The presented paper discusses all key elements of mixed-reality applications based on the presented approach. This includes camera calibration, environment model generation, real-time handling between interacting virtual and real content, shadowing for virtual content and dynamic object tracking for content planning.
Generation of 3D-TV LDV-content with Time-Of-Flight Camera

In this paper we describe an approach for 3D-TV Layered Depth Video (LDV) - Content creation using a capturing system of four CCD - Cameras and Time-Of-Flight - Sensor (ToF - Camera). We demonstrate a whole video production chain, from calibration of the camera rig, to generation of reliable depth maps for a single view of one of the CCD - Cameras, using only estimated depth provided by the ToF - Camera. We additionally show that we are able to generate proper occlusion layers for LDV - Content through a straight forward approach based on depth background extrapolation and backward texture mapping.
Optimizing the Lens Selection Process for Multi-focus Plenoptic Cameras and Numerical Evaluation

The last years have seen a quick rise of digital photography. Plenoptic cameras provide extended capabilities with respect to previous models. Multi-focus cameras enlarge the depth-of-field of the pictures using different focal lengths in the lens composing the array, but questions still arise on how to select and use these lenses. In this work a further insight on the lens selection was made, and a novel method was developed in order to choose the best available lens combination for the disparity estimation. We test different lens combinations, ranking them based on the error and the number of different lenses used, creating a mapping function that relates the virtual depth with the combination that achieves the best result. The results are then organized in a look up table that can be tuned to trade off between performances and accuracy. This allows for fast and accurate lens selection. Moreover, new synthetic images with respective ground truth are provided, in order to confirm that this work performs better than the current state of the art in efficiency and accuracy of the results.
Display-Independent 3D-TV Production and Delivery Using the Layered Depth Video Format

This paper discusses an approach to 3D-Television that is based on the Layered Depth Video (LDV) format. The LDV format contains explicit depth and occlusion information, allowing for the generation of novel viewpoints for stereoscopic and auto-stereoscopic multi-view displays. Thus, the format is effectively invariant to the display type and also allows the depth impression to be easily changed to best meet viewers' preferences for visual comfort. The major aspects of a content delivery chain based on the LDV format are discussed in this paper. The requirements placed on data acquisition are introduced, and a multi-camera system, which is well suited for LDV compliant data capture, is presented. Also discussed is the conversion of different input data streams, like standard stereo videos, multi-view data supplemented by depth data, and videos from wide baseline setups, to the LDV format. Moreover, the advantages of the LDV format in editing and mixing are examined. The paper also presents a transmission system based on currently available coding and transmission standards. Optimization of the bandwidth via different approaches to the compression of the LDV signal is analyzed, and the results of conducted experiments in this field are discussed. Finally, the aspects of perceptual human factors for the proper evaluation of 3D-TV services and the implemented LDV system are examined. This contribution reflects the efforts of the EU-funded project 3D4YOU to unify all aspects of 3D-TV production.
Truthful Color Reproduction in Spatial Augmented Reality Applications

Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized colors on the real object, because design decisions are made on basis of the projection. In this paper, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting colors on the real object are equally perceived as the real desired colors. Our approach computes the influences of the ambient light, the material, the pose and the color model of the projector to the resulting colors of the projected RGB values by using a physically based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable colors by moving the projector to arbitrary positions around the real object. We further extend the mentioned method so that it is applicable to multiple projectors. All methods are evaluated in a number of experiments.
Statistical Analysis of Kalman Filters by Conversion to Gauss-Helmert Models with Applications to Process Noise Estimation

This paper introduces a reformulation of the extended Kalman Filter using the Gauss-Helmert model for least squares estimation. By proving the equivalence of both estimators it is shown how the methods of statistical analysis in least squares estimation can be applied to the prediction and update process in Kalman Filtering. Especially the efficient computation of the reliability (or redundancy) matrix allows the implementation of self supervising systems. As an application an unparameterized method for estimating the variances of the filters process noise is presented.
A Best-Next-View-Selection Algorithm for Multi-view Rendering

In the last few years several multi-view display systems appeared increasing in size and the number of views that can be displayed. The increasing number of views allow for more realistic content with a high level of detail and complex lighting. For highest quality the images of synthetic scenes are usually ray traced. For large displays that are able to resolve a large amount of different views the number of viewing rays is enormous and it would take several month to render the content via ray tracing. One solution is to render only a few images and interpolate the remaining images with an image based rendering approach. This work introduces an algorithm that selects the best viewpoints for an image based rendering algorithm on the basis of given criteria. Special care is taken to cover occlusions and account for the dimension and angular resolution of multi-view displays.