High-resolution Texture Research Articles

Estimating spatially distributed soil texture using time series of thermal remote sensing – a case study in central Europe

Abstract. For understanding water and solute transport processes, knowledge about the respective hydraulic properties is necessary. Commonly, hydraulic parameters are estimated via pedo-transfer functions using soil texture data to avoid cost-intensive measurements of hydraulic parameters in the laboratory. Therefore, current soil texture information is only available at a coarse spatial resolution of 250 to 1000 m. Here, a method is presented to derive high-resolution (15 m) spatial topsoil texture patterns for the meso-scale Attert catchment (Luxembourg, 288 km2) from 28 images of ASTER (advanced spaceborne thermal emission and reflection radiometer) thermal remote sensing. A principle component analysis of the images reveals the most dominant thermal patterns (principle components, PCs) that are related to 212 fractional soil texture samples. Within a multiple linear regression framework, distributed soil texture information is estimated and related uncertainties are assessed. An overall root mean squared error (RMSE) of 12.7 percentage points (pp) lies well within and even below the range of recent studies on soil texture estimation, while requiring sparser sample setups and a less diverse set of basic spatial input. This approach will improve the generation of spatially distributed topsoil maps, particularly for hydrologic modeling purposes, and will expand the usage of thermal remote sensing products.

Structure- and Texture-Based Fullbore Image Reconstruction

Borehole image logs are produced by tools lowered into a well. Such logs provide oriented electrical and acoustic maps of rocks and fluids encountered in the borehole. Electrical borehole images, acquired in either water-based (conductive) or oil-based (nonconductive) muds, are generated from electrodes arranged in fixed patterns on pads pressed against the borehole wall. Depending on borehole diameter, gaps nearly always occur between pads. Because of these gaps, it is common to have nonimaged parts of the borehole wall. The existence of gaps in pad-based borehole images hinders efficient geological interpretation and accurate formation evaluation. A novel method to generate fullbore images combines an inpainting technique with FilterSim: a continuous-variable multipoint statistical approach. The inpainting algorithm detects dips and captures the trend of borehole image logs. The extracted smooth trend maps are fed into FilterSim to guide the construction of high-resolution textures that honor the original borehole image data, leading to seamless reconstruction of 360 $$^{\circ }$$ fullbore images. The proposed method has been tested using various borehole image patterns and proves to be a reliable and robust way to perform fullbore image reconstruction. The reconstructed fullbore images facilitate improved visualization and interpretation of borehole image logs in various ways, including automated dip picking for fractures and bedding planes, thin-bed analysis in deepwater formations, complex heterogeneity analysis, and accurate porosity estimation in carbonates.

ONLY IMAGE BASED FOR THE 3D METRIC SURVEY OF GOTHIC STRUCTURES BY USING FRAME CAMERAS AND PANORAMIC CAMERAS

Abstract. Indoor Gothic apse provides a complex environment for virtualization using imaging techniques due to its light conditions and architecture. Light entering throw large windows in combination with the apse shape makes difficult to find proper conditions to photo capture for reconstruction purposes. Thus, documentation techniques based on images are usually replaced by scanning techniques inside churches. Nevertheless, the need to use Terrestrial Laser Scanning (TLS) for indoor virtualization means a significant increase in the final surveying cost. So, in most cases, scanning techniques are used to generate dense point clouds. However, many Terrestrial Laser Scanner (TLS) internal cameras are not able to provide colour images or cannot reach the image quality that can be obtained using an external camera. Therefore, external quality images are often used to build high resolution textures of these models. This paper aims to solve the problem posted by virtualizing indoor Gothic churches, making that task more affordable using exclusively techniques base on images. It reviews a previous proposed methodology using a DSRL camera with 18-135 lens commonly used for close range photogrammetry and add another one using a HDR 360° camera with four lenses that makes the task easier and faster in comparison with the previous one. Fieldwork and office-work are simplified. The proposed methodology provides photographs in such a good conditions for building point clouds and textured meshes. Furthermore, the same imaging resources can be used to generate more deliverables without extra time consuming in the field, for instance, immersive virtual tours. In order to verify the usefulness of the method, it has been decided to apply it to the apse since it is considered one of the most complex elements of Gothic churches and it could be extended to the whole building.

ONLY IMAGE BASED FOR THE 3D METRIC SURVEY OF GOTHIC STRUCTURES BY USING FRAME CAMERAS AND PANORAMIC CAMERAS

Indoor Gothic apse provides a complex environment for virtualization using imaging techniques due to its light conditions and architecture. Light entering throw large windows in combination with the apse shape makes difficult to find proper conditions to photo capture for reconstruction purposes. Thus, documentation techniques based on images are usually replaced by scanning techniques inside churches. Nevertheless, the need to use Terrestrial Laser Scanning (TLS) for indoor virtualization means a significant increase in the final surveying cost. So, in most cases, scanning techniques are used to generate dense point clouds. However, many Terrestrial Laser Scanner (TLS) internal cameras are not able to provide colour images or cannot reach the image quality that can be obtained using an external camera. Therefore, external quality images are often used to build high resolution textures of these models. This paper aims to solve the problem posted by virtualizing indoor Gothic churches, making that task more affordable using exclusively techniques base on images. It reviews a previous proposed methodology using a DSRL camera with 18-135 lens commonly used for close range photogrammetry and add another one using a HDR 360° camera with four lenses that makes the task easier and faster in comparison with the previous one. Fieldwork and office-work are simplified. The proposed methodology provides photographs in such a good conditions for building point clouds and textured meshes. Furthermore, the same imaging resources can be used to generate more deliverables without extra time consuming in the field, for instance, immersive virtual tours. In order to verify the usefulness of the method, it has been decided to apply it to the apse since it is considered one of the most complex elements of Gothic churches and it could be extended to the whole building.

Automated runway groove measurement and evaluation

Grooves are frequently used on airport runways to address safety concerns by improving frictional properties and drainage capacity during wet weather. Groove performance deteriorates over time mostly due to traffic loading, accordingly periodic measurement and evaluation of groove dimensions are important for runway to maintain adequate frictional properties and avoid hydroplaning risks. However, such evaluation is difficult to perform due to lack of sufficient technologies to identify shallow and abrasive or worn grooves. This paper proposes new methodologies for automatic airport groove identification, measurement, and evaluation using high resolution texture data collected by point laser based profiling equipment developed by Federal Aviation Administration (FAA). Euler-Bernoulli beam filter and geometry contour based algorithms are developed to locate dips within a profile for potential groove identification. Subsequently improved moving average filter, forward and backward traversal methods are implemented to determine the starting and ending positions of each dip. Finally groove dimensions are computed per the FAA AC No. 150/5320-12C. The algorithm performance of the proposed method is evaluated based on Precision-Recall (PR) graphs with that of the FAA ProGroove software. Results indicate that the proposed methodology is more robust and accurate in runway groove identification. With the proposed method, operators of airfield runway pavements have a robust tool set to access groove performance and provide corrective maintenance actions.

Texture enhancement for improving single-image super-resolution performance

Although various single-image super-resolution algorithms have been developed to increase image resolution, they still do not provide adequate performance in the texture region due to the lack of fine textures in the processed image. In this paper, we present a novel texture enhancement strategy in order to improve the super-resolution performance in the texture region. For texture enhancement, we extract a low-resolution texture layer from an input image and generate a high-resolution texture layer by applying the proposed texture synthesis algorithm. A texture enhanced high-resolution image is then obtained by properly combining the generated high-resolution texture layer with an image obtained by using an existing single-image super-resolution algorithm. Experimental results show that the proposed texture enhancement strategy provides sharper and more natural looking textures compared with the existing super-resolution algorithms.

Multi-Depth-Map Raytracing for Efficient Large-Scene Reconstruction.

With the enormous advances of the acquisition technology over the last years, fast processing and high-quality visualization of large point clouds have gained increasing attention. Commonly, a mesh surface is reconstructed from the point cloud and a high-resolution texture is generated over the mesh from the images taken at the site to represent surface materials. However, this global reconstruction and texturing approach becomes impractical with increasing data sizes. Recently, due to its potential for scalability and extensibility, a method for texturing a set of depth maps in a preprocessing and stitching them at runtime has been proposed to represent large scenes. However, the rendering performance of this method is strongly dependent on the number of depth maps and their resolution. Moreover, for the proposed scene representation, every single depth map has to be textured by the images, which in practice heavily increases processing costs. In this paper, we present a novel method to break these dependencies by introducing an efficient raytracing of multiple depth maps. In a preprocessing phase, we first generate high-resolution textured depth maps by rendering the input points from image cameras and then perform a graph-cut based optimization to assign a small subset of these points to the images. At runtime, we use the resulting point-to-image assignments (1) to identify for each view ray which depth map contains the closest ray-surface intersection and (2) to efficiently compute this intersection point. The resulting algorithm accelerates both the texturing and the rendering of the depth maps by an order of magnitude.

Pavement Friction Estimation Based on the Heinrich/Klüppel Model

Tire-pavement interaction is a critical analysis for conducting friction measurements and safety evaluation on highway pavements. Substantial field studies and research efforts indicate pavement friction can be predicted with tire/texture-related models (e.g. empirical or analytical models); however, developing a reliable friction prediction model for network level pavement survey still remains a challenge. In this paper Heinrich/Klüppel friction prediction model is utilized to estimate friction on Asphalt Concrete (AC) pavements. High resolution texture data are acquired from Ames high-speed profiling system, and subsequently pavement friction data are collected on the same sections with Dynatest 6875 Highway friction tester. Findings from the study indicate a good agreement between the predicted and measured Friction Numbers (FNs). It is concluded that Heinrich/Klüppel friction theory can be used as a promising surrogate for pavement safety evaluation. This study would be beneficial for complementing the existing safety evaluation methods used in highway safety program.

Texture classification via extended local graph structure

In this paper, we propose a simple and robust local descriptor operator, called the extended local graph structure (ELGS). The original local graph structure (LGS) performs very well in many domains, for instance face recognition, face spoofing detection and others. However, LGS has a few demerits such as LGS is not robust to the noise present in the image and LGS takes into considerations the horizontal graph and ignores the vertical graph which causes a loss in the spatial information. Therefore, we extend the idea of LGS by encoding the pattern into two directions. This is means that we take into consideration the vertical graph along with the horizontal graph and then concatenate the two computed histograms features to form a global descriptor. Experimental results on the UIUC and XU High Resolution texture databases show a promising performance.

3D VIRTUALIZATION BY CLOSE RANGE PHOTOGRAMMETRY INDOOR GOTHIC CHURCH APSES. THE CASE STUDY OF CHURCH OF SAN FRANCISCO IN BETANZOS (LA CORUÑA, SPAIN)

Abstract. Virtualization using low cost photogrammetric techniques, is often replaced by Terrestial Laser Scanning inside churches. Especially in the case of Gothic churches where light penetrates the interior of the building difficulting shooting in proper condition to perform their restitution. The need to use Terrestial Laser Scaning for indoor virtualization is a significant increase in the final surveying cost. In these cases, the Terrestial Laser Scanning is used to generate dense point clouds that can produce high resolution models. However, many Terrestial Laser Scanners are not able to provide color images or can not reach the quality of images which can be obtained through a semiprofessional camera. So, digital photogrammetry is often used to make these models high resolution textures that Terrestial Laser Scanner based methodology is not capable of providing. This article aims to solved the problem posed by virtualizating Gothic churches indoors. Making that task more affordable exclusively by low cost photogrammetric techniques. The proposed methodology allows obtaining photographs in such a good conditions for virtualizing the target by point cloud. In order to verify the usefulness of the method, It has been decided to apply it to Gothic apse of the church of San Francisco in Betanzos (La Coruña). The equipment used is inexpensive and easy to carry: DSLR camera with 18-135 mm lens, tripod, lights and total station.

MACS-TumbleCam - A Novel Approach for Aerial Oblique Imaging

The ATISS measurement drone, developed at the University of Applied Sciences Wildau, is an electrical powered autonomous motor glider with a maximum take-off weight of 25 kg including a payload capacity of up to 10 kg. Two engines enable ultra short take-off procedures and the motor glider design results in a 1 h endurance. The concept of ATISS is based on the idea to strictly separate between aircraft and payload functions, which makes it a very flexible research platform for miscellaneous applications. In a project together with German Aerospace Center (DLR) this carrier was used for demonstrating a novel approach in high-resolution digital terrain modelling. A lightweight, 3D-capable photogrammetric camera called MACS-TumbleCam was developed at the DLR Berlin especially for the ATISS payload concept. The unique feature of this camera system isthe special combination of two synchronized digital cameras with an adjustable relative alignment. One camera head is oriented in a fixed nadir position while the other one can be driven to variable oblique orientations by a robotic actuator. Thus it is possible to take images from very different view directions for almost every object on the ground. Due to a parametric boresight calibration a lowcost inertial orientation system can be used. The evaluation of the first test flights shows features of the system, i.e. derived high-precision 3Dmodels of urban structures with 3 cm ground pixel resolution and high-resolution facade textures.

Finalizing a Low-Cost Photogrammetric Workflow: From Panoramic Photos to Heritage 3D Documentation and Visualization

The research aims to optimize a workflow of architecture documentation: starting from panoramic photos and tackling available instruments and technologies the aim is to propose an integrated, quick and low-cost solution of Virtual Architecture. The broader research background shows how to use spherical panoramic images for the architectural metric survey. The input data (oriented panoramic photos), the level of reliability and Image-based Modeling methods constitute an integrated and flexible 3D reconstruction approach: from the professional survey of cultural heritage to its communication in virtual museum. The proposed work results from the integration and implementation of different techniques (Multi-Image Spherical Photogrammetry, Structure from Motion, Dense Image Matching and Image-based Modeling) with the aim to achieve high metric accuracy and photorealistic performance. Different documentation chances are possible within the proposed workflow: from the virtual navigation of spherical panoramas to complex solutions of simulation and virtual reconstruction. VR tools make for the integration of different technologies and the development of new solutions for virtual navigation. Image-based Modeling techniques allow 3D model reconstruction with photo realistic and high-resolution texture. High resolution of panoramic photo and algorithms of panorama orientation and photogrammetric restitution vouch high accuracy and high-resolution texture. Automated techniques and their following integration are subject of this research. Data, advisably processed and integrated, provide different levels of analysis and virtual reconstruction joining the photogrammetric accuracy to the photorealistic performance of the shaped surfaces. Lastly, new solutions of heritage interactive and immersive communication are tested as inevitable visualization consequence of previous experimental results.

Spatial Prediction of Topsoil Texture in a Mountain-plain Transition Zone Using Unvariate and Multivariate Methods Based on Symmetry Logratio Transformation

High-resolution soil texture maps are essential for land-use planning and other activities related to forestry, agriculture and environment protection. The objective of the article was to find suitable methods for predicting soil texture through comprehensive comparison of different prediction methods (e.g., univariate and multivariate methods) by completely taking account of its characteristics as composition data with the same auxiliary information. This article, taking elevation as auxiliary variable, predicted the soil texture using univariate [ordinary kriging (OK)] and multivariate [i.e. regression kriging (RK), simple kriging with locally varying means (SKlm), and cokriging (COK)] methods. Soil texture was transformed by symmetry log ratio (SLR) to meet the requirements of the spatial interpolation for the compositional data. The root mean squared errors (RMSE), the relative improvement (RI) values of RMSE and Aitchison's distance (DA) were utilized to assess the accuracies of different prediction ...

Texture Mapping Method of Laser Point Cloud and Digital Image Based on Projection Transformation

In view of the lack of high-precision and high-resolution texture information of three-dimensional laser point cloud, this paper proposes a fusion method of three-dimensional laser point cloud and high-resolution digital images. Firstly the point cloud is transformed to the spherical image of laser intensity by projection. Then the rigorous projection transformation relation between the external digital image and three-dimensional point cloud is constructed easily through spherical image and feature information. Finally the color information of the point cloud is given by digital images. The experiment indicates that the novel method is able to avoid the layout difficulty of control points in the field and operating the three-dimensional data of indoor work, and meanwhile achieve the control of geometric accuracy.

절차적 애니메이션 방법을 이용한 인공물고기의 사실적 행동제어

인터랙티브 3D 콘텐츠에서 가상공간은 현실세계를 얼마나 충분히 반영하느냐에 따라 사용자의 심리적 만족도가 결정된다. 완성도 높은 가상공간을 표현하기 위해서는 몇 가지 요소가 필요하다. 첫째는 시각적 효과를 높이기 위해서 많은 폴리곤과 해상도 높은 텍스쳐를 이용한 모델링 기법이다. 둘째는 기능상의 효과이다. 이것은 가상공간과 사용자 또는 시스템과의 인터랙션을 통한 동적 행위들이 얼마나 사실적으로 표현되는가이다. 이를 위해 가상의 캐릭터에 대한 애니메이션 생성하고 행동을 제어 할 수 있는 기법에 대한 연구가 이루어져 왔으나 긴 제작 시간 또는 높은 비용이 소요되거나 원하는 행동을 생성하지 못하는 경우가 발생하는 문제점이 발견되어 왔다. 본 논문에서는 캐릭터의 동작을 생성하는 최적화되어 있는 골격구조를 설계하고 물리법칙과 수학적 해석을 이용한 절차적 기법을 통해 인공물고기의 행동 제어하는 방법을 제시한다. 이는 정해진 이벤트에 대해 반응하는 일대일 대응 규칙의 한계성에서 벗어나 간단한 파라미터의 조작을 통해 제작 시간을 단축하고 시각적 만족도를 높일 수 있을 것이다. In the virtual space with the interactive 3D contents, the degree of mental satisfaction is determined by how fully it reflect the real world. There are a few factors for getting the high completeness of virtual space. The first is the modeling technique with high-polygons and high-resolution textures which can heighten an visual effect. The second is the functionality. It is about how realistic represents dynamic actions between the virtual space and the user or the system. Although the studies on the techniques for animating and controlling the virtual characters have been continued, there are problems such that the long production time, the high cost, and the animation without expected behaviors. This paper suggest a method of behavior control of animation by designing the optimized skeleton which produces the movement of character and applying the procedural technique using physical law and mathematical analysis. The proposed method is free from the constraint on one-to-one correspondence rules, and reduce the production time by controlling the simple parameters, and to increase the degree of visual satisfaction.

FROM PANORAMIC PHOTOS TO A LOW-COST PHOTOGRAMMETRIC WORKFLOW FOR CULTURAL HERITAGE 3D DOCUMENTATION

Abstract. The research aims to optimize a workflow of architecture documentation: starting from panoramic photos, tackling available instruments and technologies to propose an integrated, quick and low-cost solution of Virtual Architecture. The broader research background shows how to use spherical panoramic images for the architectural metric survey. The input data (oriented panoramic photos), the level of reliability and Image-based Modeling methods constitute an integrated and flexible 3D reconstruction approach: from the professional survey of cultural heritage to its communication in virtual museum. The proposed work results from the integration and implementation of different techniques (Multi-Image Spherical Photogrammetry, Structure from Motion, Imagebased Modeling) with the aim to achieve high metric accuracy and photorealistic performance. Different documentation chances are possible within the proposed workflow: from the virtual navigation of spherical panoramas to complex solutions of simulation and virtual reconstruction. VR tools make for the integration of different technologies and the development of new solutions for virtual navigation. Image-based Modeling techniques allow 3D model reconstruction with photo realistic and high-resolution texture. High resolution of panoramic photo and algorithms of panorama orientation and photogrammetric restitution vouch high accuracy and high-resolution texture. Automated techniques and their following integration are subject of this research. Data, advisably processed and integrated, provide different levels of analysis and virtual reconstruction joining the photogrammetric accuracy to the photorealistic performance of the shaped surfaces. Lastly, a new solution of virtual navigation is tested. Inside the same environment, it proposes the chance to interact with high resolution oriented spherical panorama and 3D reconstructed model at once.

Structure of grains and grain boundaries in cryo-mechanically processed Ti alloy

A Ti5Ta1.8Nb alloy with the major phase as α (hcp) Ti has been subjected to severe plastic deformation by means of cryo-rolling. Significant grain refinement (from ~5 μm to ~60 nm) has been observed. The mechanism of grain refinement was studied by analysis of lattice strain variations with increase in cold work using XRD technique. Various intermediate stages, such as hardening, alignment of dislocations, cell formation and criticality before new grain formation, were identified. Formation of cells with dislocations alignment at the boundaries and then finally forming an ultra-fine grain structure was confirmed by transmission electron microscopy studies. Detailed grain boundary characterisation has been carried out using high-resolution transmission electron microscopy studies and crystallographic texture analysis. The grain-refined structure was found to possess a large fraction of high angle boundaries identified also as special boundaries by evaluating the misorientation angle/axis sets for a pair of adjacent grain boundaries.

3D HERITAGE DOCUMENTATION

Nowadays, realistic 3D models are achieved from high resolution texture warped to laser scanner meshes. Multiple photos are normally required for texture mapping, so many manual processes have to be implemented which are absolutely time consuming especially in large sites. The challenge is to handle these processes automatically by developing suitable algorithms. Therefore we focus here on a developed algorithm for automatic texture mapping with its corresponding software. The recent techniques are then used to recover a complete 3D model for paintings inside the Domitilla catacomb which is the largest catacomb in Rome. Such models will help archaeologists to virtually reach the catacomb without putting their feet underground and accordingly conduct their own research

Mobile Robot Self Localization and 3D Map Building using a 3D PMD-Camera for tele-robotic applications

AbstractThis work purposes using a 3D PMD camera as a sensor for mobile robot applications. The use of image sensors for environment detection is substantial and common usage in mobile robot exploration. Laser scanners, 3D stereo vision or a combination of them are be used generally. The PMD camera is a novel 3D measuring system, which is based on a time-of-flight principle. The main feature is an array sensor, which can measure the distance to the target without scanning. This relatively new technology offers a cost-effective alternative to the mentioned sensors. In the following we present methods for self-localization and 3D map building by remote sensor data acquisition. This allows the teleoperative control of a mobile robot in an unknown environment. To enhance the mobile robot tasks, a CCD and the PMD camera are registered in order to create the three dimensional mapping. The CCD texture data will be overlaid with the PMD depth data to increase the accuracy of the lateral resolution. The visual input from the CCD camera not only delivers high resolution texture data, it can also apply for object recognition in clutter environment.

Fusion of multi‐spectral SPOT‐5 images and very high resolution texture information extracted from digital orthophotos for automatic classification of complex Alpine areas

In areas with complex three‐dimensional features, slope and aspect interact with light conditions and significantly affect the spatial structure of images acquired by remote sensing instruments (for example, by changing the distribution of shadows and affecting the texture of high resolution imagery). In this scenario, this paper analyses the potential and the effectiveness of an automatic classification system to identify three fundamental vegetation classes (forest, grassland and crops) in the complex topography of the Italian Alps (Autonomous Province of Trento, Italy). This classification system is based on the fusion of spectral information provided by the SPOT‐5 multi‐spectral channels (Ground Instantaneous Field of View, GIFOV, equal to 10 m) and textural information extracted from airborne digital orthophotos (GIFOV equal to 1 m) and is designed to be user‐friendly. The texture of the digital orthophotos was modelled using defined bidirectional variograms, thereby extracting additional information unavailable in first‐order texture analyses. Using SPOT‐5 multi‐spectral information alone, the classification accuracy in the investigated alpine area was equal to 87.5%, but increased to 92.1% when texture information was included. In particular, the texture information significantly increased the classification accuracy for crops (from 68.9% to 87.9%), especially orchards that tend to be classified as lowland deciduous forests, and herbaceous crops (such as maize) that are often misclassified as grasslands. A further simple majority analysis increased the ability of detecting grassland, crops and urban zones. The combination of the majority analysis and the proposed automatic classification system seems an effective approach to classifying vegetation types in highly fragmented and complex Alpine landscapes on a regional scale.