scholarly journals SYNCHRONIZATION OF PICAM CAMERAS FOR THREE-DIMENSIONAL STUDY OF DYNAMIC MULTI-DOMAINS NATURAL SCENES

Author(s):  
L. Avanthey ◽  
L. Beaudoin ◽  
C. Villard ◽  
S. Mellouk ◽  
R. Treglia

Abstract. In this article, we study the interest of PiCam and its possibilities offered for the realization of a light payload (small and inexpensive) in order to perform the 3D reconstruction of dynamic scenes (underwater or aerial) in close-range remote sensing. We see that on these observation scales, movements of the scenes due to flora and fauna cannot be ignored if we want these objects to be part of the final model. We review the sensors used in the literature for 3D reconstruction and then present the arguments in favor of PiCam with regard to the constraints posed by the use of light and agile vectors. The main issue is the synchronization of these low cost sensors, which is not native: we explain the different steps to obtain a satisfactory synchronization rate with regard to the dynamism of the studied scenes and present the results obtained.

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 188 ◽  
Author(s):  
Kim Calders ◽  
Inge Jonckheere ◽  
Joanne Nightingale ◽  
Mikko Vastaranta

Advances in close-range and remote sensing technologies drive innovations in forest resource assessments and monitoring at varying scales. Data acquired with airborne and spaceborne platforms provide us with higher spatial resolution, more frequent coverage and increased spectral information. Recent developments in ground-based sensors have advanced three dimensional (3D) measurements, low-cost permanent systems and community-based monitoring of forests. The REDD+ mechanism has moved the remote sensing community in advancing and developing forest geospatial products which can be used by countries for the international reporting and national forest monitoring. However, there still is an urgent need to better understand the options and limitations of remote and close-range sensing techniques in the field of degradation and forest change assessment. This Special Issue contains 12 studies that provided insight into new advances in the field of remote sensing for forest management and REDD+. This includes developments into algorithm development using satellite data; synthetic aperture radar (SAR); airborne and terrestrial LiDAR; as well as forest reference emissions level (FREL) frameworks.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2981 ◽  
Author(s):  
Limei Song ◽  
Xinyao Li ◽  
Yan-gang Yang ◽  
Xinjun Zhu ◽  
Qinghua Guo ◽  
...  

The non-contact three-dimensional measurement and reconstruction techniques have played a significant role in the packaging and transportation of precious cultural relics. This paper develops a structured light based three-dimensional measurement system, with a low-cost for cultural relics packaging. The structured light based system performs rapid measurements and generates 3D point cloud data, which is then denoised, registered and merged to achieve accurate 3D reconstruction for cultural relics. The multi-frequency heterodyne method and the method in this paper are compared. It is shown that the relative accuracy of the proposed low-cost system can reach a level of 1/1000. The high efficiency of the system is demonstrated through experimental results.


2020 ◽  
Vol 12 (12) ◽  
pp. 1908
Author(s):  
Tzu-Yi Chuang ◽  
Jen-Yu Han ◽  
Deng-Jie Jhan ◽  
Ming-Der Yang

Moving object detection and tracking from image sequences has been extensively studied in a variety of fields. Nevertheless, observing geometric attributes and identifying the detected objects for further investigation of moving behavior has drawn less attention. The focus of this study is to determine moving trajectories, object heights, and object recognition using a monocular camera configuration. This paper presents a scheme to conduct moving object recognition with three-dimensional (3D) observation using faster region-based convolutional neural network (Faster R-CNN) with a stationary and rotating Pan Tilt Zoom (PTZ) camera and close-range photogrammetry. The camera motion effects are first eliminated to detect objects that contain actual movement, and a moving object recognition process is employed to recognize the object classes and to facilitate the estimation of their geometric attributes. Thus, this information can further contribute to the investigation of object moving behavior. To evaluate the effectiveness of the proposed scheme quantitatively, first, an experiment with indoor synthetic configuration is conducted, then, outdoor real-life data are used to verify the feasibility based on recall, precision, and F1 index. The experiments have shown promising results and have verified the effectiveness of the proposed method in both laboratory and real environments. The proposed approach calculates the height and speed estimates of the recognized moving objects, including pedestrians and vehicles, and shows promising results with acceptable errors and application potential through existing PTZ camera images at a very low cost.


Geosphere ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1393-1408 ◽  
Author(s):  
Reuben J. Hansman ◽  
Uwe Ring

AbstractGeological field mapping is a vital first step in understanding geological processes. During the 20th century, mapping was revolutionized through advances in remote sensing technology. With the recent availability of low-cost remotely piloted aircraft (RPA), field geologists now routinely carry out aerial imaging without the need to use satellite, helicopter, or airplane systems. RPA photographs are processed by photo-based three-dimensional (3-D) reconstruction software, which uses structure-from-motion and multi-view stereo algorithms to create an ultra-high-resolution, 3-D point cloud of a region or target outcrop. These point clouds are analyzed to extract the orientation of geological structures and strata, and are also used to create digital elevation models and photorealistic 3-D models. However, this technique has only recently been used for structural mapping. Here, we outline a workflow starting with RPA data acquisition, followed by photo-based 3-D reconstruction, and ending with a 3-D geological model. The Jabal Hafit anticline in the United Arab Emirates was selected to demonstrate this workflow. At this anticline, outcrop exposure is excellent and the terrain is challenging to navigate due to areas of high relief. This makes for an ideal RPA mapping site and provides a good indication of how practical this method may be for the field geologist. Results confirm that RPA photo-based 3-D reconstruction mapping is an accurate and cost-efficient remote sensing method for geological mapping.


Author(s):  
L. M. Galantucci ◽  
F. Lavecchia ◽  
G. Percoco

Considerable research effort has been focused on evaluating the accuracy of meso- and macroscale digital close range photogrammetry. However, evaluations of accuracy and applications in the submillimeter scale are rare. In this paper the authors propose the development of a three-dimensional (3D) photogrammetric scanner, based on macrolens cameras, able to reconstruct the three-dimensional surface topography of objects with submillimeter features. The system exploits multifocal image composition and has been designed for installation on all types of Numerical Controlled or Robotic systems. The approach is exploitable for digitizing submillimeter features at mesoscale as well as macroscale objects.


Author(s):  
Zihan Liu ◽  
Guanghong Gong ◽  
Ni Li ◽  
Zihao Yu

Three-dimensional (3D) reconstruction of a human head with high precision has promising applications in scientific research, product design and other fields. However, it still faces resistance from two factors. One is inaccurate registration caused by symmetrical distribution of head feature points, and the other is economic burden due to high-accuracy sensors. Research on 3D reconstruction with portable consumer RGB-D sensors such as the Microsoft Kinect has been highlighted in recent years. Based on our multi-Kinect system, a precise and low-cost three-dimensional modeling method and its system implementation are introduced in this paper. A registration method for multi-source point clouds is provided, which can reduce the fusion differences and reconstruct the head model accurately. In addition, a template-based texture generation algorithm is presented to generate a fine texture. The comparison and analysis of our experiments show that our method can reconstruct a head model in an acceptable time with less memory and better effect.


Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1497 ◽  
Author(s):  
Tiago Madeira ◽  
Miguel Oliveira ◽  
Paulo Dias

Three-dimensional (3D) reconstruction methods generate a 3D textured model from the combination of data from several captures. As such, the geometrical transformations between these captures are required. The process of computing or refining these transformations is referred to as alignment. It is often a difficult problem to handle, in particular due to a lack of accuracy in the matching of features. We propose an optimization framework that takes advantage of fiducial markers placed in the scene. Since these markers are robustly detected, the problem of incorrect matching of features is overcome. The proposed procedure is capable of enhancing the 3D models created using consumer level RGB-D hand-held cameras, reducing visual artefacts caused by misalignments. One problem inherent to this solution is that the scene is polluted by the markers. Therefore, a tool was developed to allow their removal from the texture of the scene. Results show that our optimization framework is able to significantly reduce alignment errors between captures, which results in visually appealing reconstructions. Furthermore, the markers used to enhance the alignment are seamlessly removed from the final model texture.


2013 ◽  
Vol 373-375 ◽  
pp. 638-643
Author(s):  
Zhuo Wei Hu ◽  
Lai Wei ◽  
Qian Zhang

Unmanned Aerial Vehicle (UAV) remote sensing technology has the real-time ability to obtain ground images at earthquake landslide area. It makes it possible to extract landslide disaster information, support emergency rescue and decrease losses at the first second after earthquake. However, UAV remote sensing is prone to produce images with big-slant-angle. Although it is not fit for object measuring by traditional photogrammetry, it is benefit for observing slope at a better angle and extracting slope characteristics quantitatively. In this research, we define UAV big-slant-angle data as side-look images for earthquake landslide, which is based on an UAV close range photogrammetry idea. Image recognition of earthquake landslide area and three dimensional measuring of slope features will be researched. First of all, a projection datum plane along slope normal will be simulated according to the terrain surface. Appropriate images will be selected by evaluating camera pose and landslide overlapping rate. Secondly, orthogonal rotation matrixes are used to do 3D datum transformation with big-rotation-angle. Settlement of collinearity equations considering big-slant-angle condition will be researched. On this basis, dependent relative orientation among image series will be done to construct a three dimensional side-look-image model. At last, landslide image recognition, slope terrain surface reconstruction and landslide feature measurement is considered to cover the contents of earthquake landslide information extraction. Structural features and combined features can be analyzed and calculated on this basis. A rigorous solution of forward intersection in close range photogrammetry with big-slant-angle will be researched. Slope feature geometry and its relationship among images are to be considered to make a credible characteristic matching thinking big-rotation-angle exists. It has potentiality to provide variety landslide information with higher geometrical precision for cartography and risk analysis of earthquake landslide.


Author(s):  
A. Cardaci ◽  
A. Versaci ◽  
P. Azzola

Abstract. The creation of three-dimensional models for the cataloguing and documentation of cultural heritage is today an emerging need in the cultural sphere and, above all, for museums. The cultural heritage is still catalogued and documented based on descriptive files assorted of photographic images which, however, fail to outline its spatial richness, possible only through the use of 3D artefacts. The essay aims to propose a methodology of digitalization by low-cost and easy-to-use systems, to be employed even by non-expert survey and photogrammetry’s operators. The case study of the statue of San Nicola da Tolentino, preserved at the Sant’Agostino complex in Bergamo, offered the possibility of a comparison between 3D models acquired with different digitalization tools (professional/action/amateur cameras and smartphone) and processed by several image-based 3D Reconstruction software and methods.


Author(s):  
C. Tejeda-Sánchez ◽  
A. Muñoz-Nieto ◽  
P. Rodríguez-Gonzálvez

Visualization and analysis use to be the final steps in Geomatics. This paper shows the workflow followed to set up a hybrid 3D archaeological viewer. Data acquisition of the site survey was done by means of low-cost close-range photogrammetric methods. With the aim not only to satisfy the general public but also the technicians, a large group of Geomatic products has been obtained (2d plans, 3d models, orthophotos, CAD models coming from vectorization, virtual anastylosis, and cross sections). Finally, all these products have been integrated into a three-dimensional archaeological information system. The hybrid archaeological viewer designed allows a metric and quality approach to the scientific analysis of the ruins, improving, thanks to the implementation of a database, and its potential for queries, the benefits of an ordinary topographic survey.


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