scholarly journals TECHNICAL CONSIDERATIONS IN LOW-COST HERITAGE DOCUMENTATION

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 225-232
Author(s):  
A. Murtiyoso ◽  
P. Grussenmeyer ◽  
D. Suwardhi
Keyword(s):  
Point Cloud ◽  
Low Cost ◽  
Bundle Adjustment ◽  
Ease Of Use ◽  
Cloud Data ◽  
Heritage Sites ◽  
Common Reference ◽  
Trade Offs ◽  
Dense Point

Abstract. The use of photogrammetry in 3D heritage documentation has matured over the recent years. In the same time, many types of sensors have also been developed in the field of imaging. While photogrammetry is considered as a low-cost alternative to TLS, several options exist in terms of sensor type with trade-offs between price, ease of use, and quality of resolution. Nevertheless, a proper knowledge on the acquisition and processing is still required to generate acceptable results. This paper aims to compare three photogrammetric sensors, namely a classical DSLR camera, a drone, and a spherical 360° camera in documenting heritage sites. Main comparison points include quality of the bundle adjustment and quality of the dense point cloud. However, an important point of the paper is also to determine whether a sensor at a given cost and effort is enough for documentation purposes. A TLS point cloud data was used as a common reference, as well as control and check points issued from geodetic surveying. In the aftermath of the comparison, several technical suggestions and recommendations were proposed as regards to the use of each sensor.

scholarly journals THE POWER LINE HEIGHT ANALYSIS CHART DRAWING BASE ON MAPMATRIX

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 327-333
Author(s):  
Y. R. He ◽  
W. W. Ma ◽  
X. R. Wang ◽  
J. Q. Dai ◽  
J. L. Zheng
Keyword(s):  
Point Cloud ◽  
Remote Sensing Data ◽  
Field Investigation ◽  
Power Line ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Binocular Stereo Vision ◽  
Binocular Stereo ◽  
Aerial Vehicle

Abstract. The power patrol has been completed by manual field investigation, which is inefficient, costly and unsafe. In order to extract the height of the power line and its surrounding ground objects more quickly and conveniently, and better service for power line patrol. This paper uses remote sensing data of unmanned aerial vehicle to carry out aerial triangulation, stereo model establishment and binocular stereo vision height extraction base on MapMatrix software, then obtains the power line height analysis chart. Then LiDAR point cloud data is used to verify the accuracy of the power line height analysis chart. The results show that this method not only meets the standard of power line patrol, but also improves the efficiency and quality of power line patrol.

scholarly journals GEOREFERENCING AND REPROJECTION ERROR INVESTIGATION ON IMAGE BASED 3D DIGITIZATION AND MAPPING OF HISTORICAL BUILDINGS

2019 ◽  
Vol XLII-2/W11 ◽  
pp. 71-75
Author(s):  
C. Altuntas
Keyword(s):  
Point Cloud ◽  
Large Scale ◽  
Cloud Model ◽  
Low Cost ◽  
Three Dimensional ◽  
Control Points ◽  
Historical Buildings ◽  
Reprojection Error ◽  
Dense Point ◽  
Point Cloud Model

<p><strong>Abstract.</strong> Image based dense point cloud creation is easy and low-cost application for three dimensional digitization of small and large scale objects and surfaces. It is especially attractive method for cultural heritage documentation. Reprojection error on conjugate keypoints indicates accuracy of the model and keypoint localisation in this method. In addition, sequential registration of the images from large scale historical buildings creates big cumulative registration error. Thus, accuracy of the model should be increased with the control points or loop close imaging. The registration of point point cloud model into the georeference system is performed using control points. In this study historical Sultan Selim Mosque that was built in sixteen century by Great Architect Sinan was modelled via photogrammetric dense point cloud. The reprojection error and number of keypoints were evaluated for different base/length ratio. In addition, georeferencing accuracy was evaluated with many configuration of control points with loop and without loop closure imaging.</p>

The Research of Point Cloud Data Processing Technology

2014 ◽  
Vol 628 ◽  
pp. 426-431
Author(s):  
Li Bo Zhou ◽  
Fu Lin Xu ◽  
Su Hua Liu
Keyword(s):  
Data Processing ◽  
Point Cloud ◽  
Quality Data ◽  
Surface Generation ◽  
Point Cloud Data ◽  
Data Smoothing ◽  
Cloud Data ◽  
Data Point ◽  
Cloud Data Processing

Data processing is a key to reverse engineering, the results of which will directly affect the quality of the model reconstruction. Eliminate noise points are the first step in data processing, The method of using Coons surface to determine the noise in the data point is proposed. To reduce the amount of calculation and improve the surface generation efficiency, data point is reduced. According to the surrounding point coordinate information, the defect coordinates are interpolated. Data smoothing can improve the surface generation quality, data block can simplify the creation of the surface. Auto parts point cloud data is processed, and achieve the desired effect.

The Use of the Terrestrial Photogrammetry in Reverse Engineering Applications

2015 ◽  
Vol 4 (2) ◽  
pp. 48-57
Author(s):  
Naci Yastikli ◽  
Zehra Erisir ◽  
Pelin Altintas ◽  
Tugba Cak
Keyword(s):  
Reverse Engineering ◽  
Point Cloud ◽  
Low Cost ◽  
Line Drawing ◽  
Engineering Application ◽  
3D Models ◽  
Engineering Applications ◽  
Ship Model ◽  
Dense Point ◽  
Terrestrial Photogrammetry

The reverse engineering applications has gained great momentum in industrial production with developments in the fields of computer vision and computer-aided design (CAD). The reproduction of an existing product or a spare part, reproduction of an existing surface, elimination of the defect or improvement of the available product are the goals of industrial reverse engineering applications. The first and the most important step in reverse engineering applications is the generation of the three dimensional (3D) metric model of an existing product in computer environment. After this stage, many operations such as the preparation of molds for mass production, the performance testing, the comparison of the existing product with other products and prototypes which are available on the market are performed by using the generated 3D models. In reverse engineering applications, the laser scanner system or digital terrestrial photogrammetry methods, also called contactless method, are preferred for the generation of the 3D models. In particular, terrestrial photogrammetry has become a popular method since require only photographs for the 3-dimensional drawing, the generation of the dense point cloud using the image matching algorithms and the orthoimage generation as well as its low cost. In this paper, an industrial application of 3D information modelling is presented which concerns the measurement and 3D metric modelling of the ship model. The possible usage of terrestrial photogrammetry in reverse engineering application is investigated based on low cost photogrammetric system. The main aim was the generation of the dense point cloud and 3D line drawing of the ship model by using terrestrial photogrammetry, for the production of the ship in real size as a reverse engineering application. For this purpose, the images were recorded with digital SLR camera and orientations have been performed. Then 3D line drawing operations, point cloud and orthoimage generations have been accomplished by using PhotoModeler software. As a result of the proposed terrestrial photogrammetric steps, 0.5 mm spaced dense point cloud and orthoimage have been generated. The obtained results from experimental study were discussed and possible use of proposed methods was evaluated for reverse engineering application.

Acquisition of Point Cloud Data in 3D Reconstruction

2014 ◽  
Vol 536-537 ◽  
pp. 213-217
Author(s):  
Meng Qiang Zhu ◽  
Jie Yang
Keyword(s):  
3D Reconstruction ◽  
Camera Calibration ◽  
Point Cloud ◽  
Corner Detection ◽  
Projection Mapping ◽  
Cloud Data ◽  
3D Space ◽  
Dense Point ◽  
Left And Right ◽  
Object Depth

This paper takes the following measures to solve the problem of 3D reconstruction. Camera calibration is based on chessboard, taking several different attitude images. Use corner point coordinates by corner detection to process camera calibration. The calibration result is important to be used to correct the distorted image. Next, the left and right images should be matched to find out the object surface points’ imaging position respectively so that the object depth can be calculated by triangulation. According to the inverse process of projection mapping, we can project the object depth and disparity information into 3D space. As a result, we can obtain dense point cloud, which is ready for 3D reconstruction.

Understory biomass measurement based on SfM data by a manual low-flying drone under the canopy

2020 ◽  
Author(s):  
Yupan Zhang ◽  
Yuichi Onda ◽  
Hiroaki Kato ◽  
Xinchao Sun ◽  
Takashi Gomi
Keyword(s):  
Point Cloud ◽  
Light Availability ◽  
Understory Vegetation ◽  
Airborne Lidar ◽  
Vegetation Coverage ◽  
Coefficient Of Determination ◽  
Small Scale ◽  
Cloud Data ◽  
Dense Point ◽  
Understory Biomass

&lt;p&gt;Understory vegetation has the important effect that cannot be ignored on Evapotranspiration. In previous studies, laser scanner was used to measure small-scale biomass and airborne LiDAR was used to assess light availability to understory vegetation, which in turn was converted to understory biomass production. However, it is difficult to measure watershed-scale understory biomass with high resolution. In this study, Structure from Motion (SfM) was used to reconstruct understory vegetation structure by a manual low-flying drone under the canopy with radial paths in a line thinning plantation and a spot thinning plantation made by Japanese cedar and cypress. By generating Orthomosaic image and dense point cloud data, we then extracted Excess Green Index (ExG) and Canopy Height Model (CHM), combining with understory biomass data from field harvesting to establish a quantitative relationship between the CHM and biomass, which was then used to map biomass and vegetation coverage in the study area. The results indicated that (1) a flight height of 7-10 meters is more conducive to understory vegetation reconstruction, with a photo quality greater than 0.8 and a point cloud density of more than 20 points/cm&lt;sup&gt;2&lt;/sup&gt;. (2) a regression cubic model based on the CHM has acceptable accuracy and biomass estimate capability (P&lt;0.01), with a coefficient of determination of 0.75. (3) compared with the spot thinning, the understory biomass under the line thinning scenario was higher(average biomass 3.03kg/m&lt;sup&gt;2&lt;/sup&gt;). (4) vegetation coverage based on the ExG index of visible light analysis was affected by ambient light(strong sunlight on a sunny day), and it cannot reflect the seasonal changes of understory vegetation biomass. These results disclosed the potential of the dense point cloud from drone SfM for estimating understory biomass. With this method, we will measure more than 5000m&lt;sup&gt;2 &lt;/sup&gt;of headwater catchment and output a understory biomass map.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals THE SYSTEM OVERVIEW AND GEOMETRIC IMAGE QUALITY OF THE TH-1 SATELLITE

2016 ◽  
Vol XLI-B1 ◽  
pp. 511-516
Author(s):  
Jianrong Wang ◽  
Xin Hu
Keyword(s):  
Low Cost ◽  
Bundle Adjustment ◽  
Topographic Mapping ◽  
Location Accuracy ◽  
Ground Control Points ◽  
Satellite Platform ◽  
Equivalent Frame ◽  
Camera Parameters ◽  
Th 1

The Tian-Hui 1 (TH-1) is the first stereo mapping transmission satellite in China, and the primary mission goal of the satellite is for topographic mapping at 1:50,000 scale without Ground Control Points (GCPs). 1st, 2nd and 3rd satellite of TH-1 was launched on August 24, 2010, May 6, 2012 and October 26, 2015. In TH-1 satellite, many payloads are put on a small satellite platform, which has a low cost. The optical camera of TH-1 includes Line-Matrix CCD (LMCCD) camera, high resolution camera and multispectral camera with 60 km ground swath width. To get high geometric accuracy without GCPs, the on-orbit calibration camera parameters and the Equivalent Frame Photo (EFP) Multi-functional bundle adjustment are proposed and realized in ground image processing of TH-1. In order to evaluate the location accuracy of TH-1, some testing fields are established. All GCPs of testing fields are measured by GPS. The GCPs are not participated the EFP Multi-functional bundle adjustment, and are only as Check Points (CPs) to evaluate the location accuracy. The evaluation of 1st satellite is shown: the horizontal accuracy is 10.3 m (RMSE) and the vertical accuracy is 5.7 m (RMSE) without GCPs, which can satisfy for topographic mapping at 1:50,000 scale. The overviews of TH-1 satellite are described in this paper: First, the system overview is introduced, including mission and optical camera of TH-1. Then, the on-orbit calibration camera parameters using LMCCD image and the EFP Multi-functional bundle adjustment are presented. Finally, the location performance is analysed without GCPs and with different number of GCPs. In addition, the products of TH-1 are introduced.

scholarly journals CORS ARCHITECTURE AND EVALUATION OF POSITIONING BY LOW-COST GNSS RECEIVER

2018 ◽  
Vol 44 (2) ◽  
pp. 36-44 ◽  
Author(s):  
Massimiliano Pepe
Keyword(s):  
Low Cost ◽  
Satellite System ◽  
Ease Of Use ◽  
Quality Data ◽  
Gnss Receiver ◽  
Stop And Go ◽  
Gnss Receivers ◽  
Spatial Positioning ◽  
Global Navigation Satellite

In recent years, the use of low cost GNSS receivers is becoming widespread due to their increasing performance in the spatial positioning, flexibility, ease of use and really interesting price. In addition, a recent technique of Global Navigation Satellite System (GNSS) survey, called Network Real Time Kinematic (NRTK), allows to obtain to rapid and accurate positioning measurements. The main feature of this approach is to use the raw measurements obtained and stored from a network of Continuously Operating Reference Stations (CORS) in order to generate more reliable error models that can mitigate the distance-dependent errors within the area covered by the CORS. Also, considering the huge potential of this GNSS positioning system, the purpose of this paper is to analyze and investigate the performance of the NTRK approach using a low cost GNSS receiver, in stop-and-go kinematic technique. By several case studies it was shown that, using a low cost RTK board for Arduino environment, a smartphone with open source application for Android and the availability of data correction from CORS service, a quick and accurate positioning can be obtained. Because the measures obtained in this way are quite noisy and, more in general, increasing with the baseline, by a simple and suitable statistic treatment, it was possible to increase the quality of the measure. In this way, this low cost architecture could be applied in many geomatics fields. In addition to presenting the main aspects of the NTRK infrastructure and a review of several types of correction, a general workflow in order to obtain quality data in NRTK mode, regardless of the type of GNSS receiver (multi constellations, single or many frequencies, etc.) is discussed.

scholarly journals TRIANGULATION AND TIME-OF-FLIGHT BASED 3D DIGITISATION TECHNIQUES OF CULTURAL HERITAGE STRUCTURES

2021 ◽  
Vol XLIII-B2-2021 ◽  
pp. 825-830
Author(s):  
C. Altuntas
Keyword(s):  
Cultural Heritage ◽  
Laser Scanning ◽  
Low Cost ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Time Of Flight ◽  
Cost Effective ◽  
Cloud Data ◽  
Dense Point

Abstract. This study aims to introduce triangulation and ToF measurement techniques used in three-dimensional modelling of cultural heritages. These measurement techniques are traditional photogrammetry, SfM approach, laser scanning and time-of-flight camera. The computer based approach to photogrammetric measurement that is named SfM creates dense point cloud data in a short time. It is low-cost and very easy to application. However traditional photogrammetry needs a huge effort for creating 3D wire-frame model. On the other hand active measurement techniques such as terrestrial laser scanner and time-of-flight camera have also been used in three-dimensional modelling for more than twenty years. Each one has specific accuracy and measurement effectiveness. The large or small structures have different characters, and require proper measurement configurations. In this study, after these methods are introduced, their superior and weak properties in cultural heritage modelling to make high accuracy, high density and labour and cost effective measurement.

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