Estimation of Mean Trace Length Based on Trace Maps Measured by GPS-RTK

2014 ◽  
Vol 638-640 ◽  
pp. 2141-2145 ◽  
Author(s):  
Jian Zheng ◽  
Yang Song Zhang ◽  
Xing Xi Shi ◽  
Xiao Zhao Li
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Measurement Data ◽  
Reference Value ◽  
Trace Length ◽  
Digital Terrain ◽  
Real Time Kinematic ◽  
Gps Rtk ◽  
The Mean ◽  
Trace Maps

Based on measurement data acquired by GPS-RTK (Real Time Kinematic) technology, this paper established a three-dimensional traces model on digital terrain. Then Zhang and Einstein method and H-H method were chosen to estimate the mean trace length of discontinuities. The results using these two methods are both very close to the reference value. It shows the feasibility of these methods and the rules for setting digital windows in this case.

An Explicit Non-Real Time Data Reduction Method of Triple Sensors Hot-Wire Anemometer in Three-Dimensional Flow

1988 ◽  
Vol 110 (2) ◽  
pp. 110-119 ◽  
Author(s):  
Y. T. Chew ◽  
R. L. Simpson
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Computation Time ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Time Data ◽  
Three Dimensional Flow ◽  
Mean Velocity ◽  
Dimensional Flow ◽  
The Mean

An explicit non-real time method of reducing triple sensor hot-wire anenometer data to obtain the three mean velocity components and six Reynolds stresses, as well as their turbulence spectra in three-dimensional flow is proposed. Equations which relate explicitly the mean velocity components and Reynolds stresses in laboratory coordinates to the mean and mean square sensors output voltages in three stages are derived. The method was verified satisfactorily by comparison with single sensor hot-wire anemometer measurements in a zero pressure gradient incompressible turbulent boundary layer flow. It is simple and requires much lesser computation time when compared to other implicit non-real time method.

scholarly journals Preliminary Outcomes Following Application Of The Real-Time Navigation System Combined With Intraoperative Three-Dimensional C-Arm Computed Tomography For Zygomatico-Orbital Fracture Reconstruction

2021 ◽  
Author(s):  
Yu-Ying Chu ◽  
Jia-Ruei Yang ◽  
Han Tsung Liao ◽  
Bo-Ru Lai
Keyword(s):  
Computed Tomography ◽  
Real Time ◽  
Navigation System ◽  
Surgical Navigation ◽  
Three Dimensional ◽  
Orbital Fracture ◽  
The Real ◽  
Orbital Volume ◽  
Surgical Navigation System ◽  
The Mean

Abstract This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. ±1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm3 (P <0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

scholarly journals Aplikasi GPS RTK untuk Pemetaan Bidang Tanah

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Joko Setiadi
Keyword(s):  
Real Time ◽  
Field Measurements ◽  
Process Efficiency ◽  
Gps Receiver ◽  
Point Position ◽  
Advantages And Disadvantages ◽  
Real Time Kinematic ◽  
Gps Rtk ◽  
Point Positioning ◽  
Rtk Gps

Abstrak Penggunaan receiver GPS RTK (Real Time Kinematic) pada metode ekstraterestrial untuk penentuan posisi titik saat ini sudah banyak diterapkan. Penelitian ini bertujuan mengkaji sampai sejauh mana ketelitian posisi titik yang diperoleh dari hasil pengukuran secara ekstraterestrial menggunakan GPS RTK untuk pemetaan bidang-bidang tanah berikut kekurangan dan kelebihannya. Dari hasil pengukuran didapat ketelitian rata-rata hasil pengukuran posisi titik menggunakan GPS RTK dibandingkan dengan menggunakan alat ETS (Electronic Total Station) adalah sebesar 0,214 m sehingga dapat diterapkan untuk pembuatan peta skala 1 : 500. Untuk daerah yang terbuka, pengukuran bidang tanah menggunakan GPS RTK memerlukan waktu dua kali lebih cepat dibandingkan dengan ETS. Walaupun GPS RTK mempunyai keunggulan dalam hal efisiensi proses pengukuran di lapangan sehingga dapat mempersingkat waktu pengukuran, akan tetapi memiliki kekurangan dalam hal ketelitian data terutama pada area pengukuran yang tertutup. Kata kunci: GPS RTK, ETS, posisi titik, ekstraterestrial.   Abstract The use of RTK GPS receiver (Real Time Kinematic) on extraterrestrial method for point positioning h widely applied. The purpose of this study is to examine the point position accuracy obtained from the measurements using GPS RTK for extraterrestrial mapping plots, including its advantages and disadvantages. Measurement accuracy of the results obtained from the average measurement point positioning using GPS RTK compared using the ETS tool is equal to 0.214 m, so that it can be applied for map making of scale 1: 500. For open areas, field measurements using GPS RTK can be performed by two times faster than using ETS. Although GPS RTK has advantages in terms of measurements process efficiency in the field so as to shorten the time of measurement, but has shortcomings in terms of accuracy of the data, especially in an enclosed area measuring. Keywords: GPS RTK , ETS, point position, extraterrestrial.

Abstract 4562: Real-time Transthoracic Three-dimensional Echocardiography Provides Valuable Management Information in Double Outlet Right Ventricle: An Echocardiographic-surgical Correlative study

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Akio Inage ◽  
Ken Takahashi ◽  
Ivan Rebeyka ◽  
David Ross ◽  
Jeffrey F Smallhorn
Keyword(s):  
Right Ventricle ◽  
Real Time ◽  
Tricuspid Valve ◽  
Three Dimensional ◽  
Double Outlet Right Ventricle ◽  
Left Ventricular ◽  
The Mean ◽  
Dimensional Echocardiography ◽  
Three Dimensional Echocardiography ◽  
Relationship Of

Objective: To assess the incremental value of real-time transthoracic three-dimensional echocardiography (RT3DE), over two-dimensional echocardiography (2DE) in determining the adequacy of the interventricular communication (IC) and surrounding structures in double outlet right ventricle (DORV). Background: The IC size which is crucial to the management of DORV is different from the “hole” closed by the surgeon. If the IC communication is too small post operative left ventricular outflow tract obstruction can occur. Methods: Twenty patients with DORV, mean age of 1.2 years (range 0 day to 8 years) and mean body weight of 7.1 kg (range 3.1 to 21.8 kg), were examined with RT3DE, as well as 2DE. Full volume RT3DE data sets were acquired in all, using either an X3–1 or X7–2 Matrix-Array transducer (Philips Medical System). Data analysis was performed using offline Philips QLabs. We measured end diastolic (ED) and end systolic (ES) area of the IC and the “hole” closed by the surgeons by RT3DE and 2DE, and adjusted them by body surface area (BSA). As well, we measured the tricuspid to aortic and tricuspid to pulmonary valve distance (TV-AV and TV-PV distance) by RT3DE and determined the relationship of the tricuspid valve to the IC. Results: Four patients had an associated muscular VSD. The mean ED and ES IC area/BSA were 7.33 ± 3.94 and 4.25 ± 1.86 cm 2 /m 2 by RT3DE and 3.41 ± 1.9 and 2.00 ± 1.29 cm 2 /m 2 by 2DE respectively. The mean ED and ES “surgical hole” area/BSA were 10.62 ± 3.94 and 6.52 ± 2.65 cm 2 /m 2 by RT3DE and 5.90 ± 2.47 and 4.27 ± 1.36 cm 2 /m 2 by 2DE respectively. ED and ES IC and “surgical hole” areas were significantly different between RT3DE and 2DE (P value ranges: 0.024 to < 0.001). 2DE tended to underestimate IC and the “surgical hole” size. The TV-AV and TV-PV distance relationship by RT3DE could be determined and was consistent with current surgical practice for DORV. The precise relationship of tricuspid valve attachments in the vicinity of the IC were readily determined by RT3DE, but not by 2DE. Conclusion: RT3DE provides useful and additive information, and offers simulated intraoperative visualization of true IC and the “surgical hole” in DORV as well as the surrounding structures.

scholarly journals Quality Assessment of Photogrammetric Models for Façade and Building Reconstruction Using DJI Phantom 4 RTK

2020 ◽  
Vol 12 (19) ◽  
pp. 3144
Author(s):  
Yuri Taddia ◽  
Laura González-García ◽  
Elena Zambello ◽  
Alberto Pellegrinelli
Keyword(s):  
Real Time ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Ground Sample ◽  
Aerial Photogrammetry ◽  
Ground Control Points ◽  
Real Time Kinematic ◽  
Camera Location ◽  
Scale Range ◽  
Oblique Images

Aerial photogrammetry by Unmanned Aerial Vehicles (UAVs) is a widespread method to perform mapping tasks with high-resolution to reconstruct three-dimensional (3D) building and façade models. However, the survey of Ground Control Points (GCPs) represents a time-consuming task, while the use of Real-Time Kinematic (RTK) drones allows for one to collect camera locations with an accuracy of a few centimeters. DJI Phantom 4 RTK (DJI-P4RTK) combines this with the possibility to acquire oblique images in stationary conditions and it currently represents a versatile drone widely used from professional users together with commercial Structure-from-Motion software, such as Agisoft Metashape. In this work, we analyze the architectural application of this drone to the photogrammetric modeling of a building with particular regard to metric survey specifications for cultural heritage for 1:20, 1:50, 1:100, and 1:200 scales. In particular, we designed an accuracy assessment test signalizing 109 points, surveying them with total station and adjusting the measurements through a network approach in order to achieve millimeter-level accuracy. Image datasets with a designed Ground Sample Distance (GSD) of 2 mm were acquired in Network RTK (NRTK) and RTK modes in manual piloting and processed both as single façades (S–F) and as an overall block (4–F). Subsequently, we compared the results of photogrammetric models generated in Agisoft Metashape to the Signalized Point (SP) coordinates. The results highlight the importance of processing an overall photogrammetric block, especially whenever part of camera locations exhibited a poorer accuracy due to multipath effects. No significant differences were found between the results of network real-time kinematic (NRTK) and real-time kinematic (RTK) datasets. Horizontal residuals were generally comparable to GNSS accuracy in NRTK/RTK mode, while vertical residuals were found to be affected by an offset of about 5 cm. We introduced an external GCP or used one SP per façade as GCP, assuming a poorer camera location accuracy at the same time, in order to fix this issue and comply with metric survey specifications for the widest architectural scale range. Finally, both S–F and 4–F projects satisfied the metric survey requirements of a scale of 1:50 in at least one of the approaches tested.

scholarly journals Method of Real-Time Wellbore Surface Reconstruction Based on Spiral Contour

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 291
Author(s):  
Hongqiang Li ◽  
Ruihe Wang
Keyword(s):  
Surface Structure ◽  
Real Time ◽  
Surface Reconstruction ◽  
Three Dimensional ◽  
Measurement Data ◽  
Surface Profile ◽  
Contour Line ◽  
Actual Measurement ◽  
Iterative Interpolation ◽  
Reconstructed Surface

A wellbore surface is an irregular surface structure. The distribution of points on the wellbore surface measured based on the drilling diameter is not uniform. Thus, the conventional modeling method based on a point cloud cannot satisfy the needs of real-time measurement updating and wellbore display. This study proposes a spiral profile method for drilling shaft surface reconstruction. Scattered data along the drilling diameter are measured, and an inverse distance weighting cylindrical space surface algorithm with iterative interpolation is used to obtain the spiral angle and pitch of a relatively homogeneous helical contour line along the surface of the shaft. Using sets of four adjacent points in the spiral, quadrilaterals are formed, and then all obtained quadrilaterals are used to form the wellbore inner surface structure. This method can further construct the outer surface spiral contour line to advance the quadrilateral surface to the spatial hexahedron structure. The caliper and gamma measurement data obtained from the calibrated wellbore were used to verify the real-time surface reconstruction and fusion while drilling. The homogenized reconstructed surface profile is more than 99.5% similar to the actual measurement. Proved by experiment and application, this method has very high real-time performance, and the three-dimensional stereo imaging wellbore with additional gamma attributes has good visual effects.

The Research on Mean Spacing of Rock Fracture

2014 ◽  
Vol 580-583 ◽  
pp. 219-223
Author(s):  
Lu Jiang ◽  
Yang Song Zhang
Keyword(s):  
Rock Mass ◽  
Linear Density ◽  
Rock Fracture ◽  
Three Dimensional ◽  
Gansu Province ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Gps Rtk ◽  
Mass Classification ◽  
The Mean

The mean spacing of rock fracture is a very important parameter base to evaluate rock mass,a number of rock studies base on it. Object of this paper is Beishan preselected area in Gansu Province, China. A uthor use GPS-RTK to measure the fracture’s endpoints and inflection, then process the resulting coordinate, building a three-dimensional model of rock fracture by using three-dimensional software and meshing the three-dimensional model, Through the analysis of fractures in each grid to calculate the linear density of rock fracture, after the orientation and inclination correction on linear density, it can be converted to an mean spacing of rock fractures. The mean spacing of rock fracture can be directly used for rock mass classification in GSI rock systems, and has a great significance in rock engineering studies.

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