Academic literature on the topic 'Cloudcompare'

Framställning av digitala terrängmodell (Digital Terrain Model, DTM) är en viktig del för projekteringsunderlag vid markrelaterade frågor. Grunden för en DTM är punktmolnet som innehåller grunddata från mätningen. DTM är användbara i många olika områden, kvalitén bestäms beroende på vilken uppdrag som DTM gäller för. UAS-fotogrammetri är en av metoder som tillämpas för att framställa en DTM, det går även att framställa en DTM utifrån punktmoln från Laserdata NH. En DTM är en modell av endast markyta, där data samlas genom mätning av ett visst objekt. Syftet med detta examensarbete som är utfört vid Institutionen för ingenjörsvetenskap vid Högskolan Väst var att jämföra två olika metoder för framställning av ett punktmoln som är till underlag för en DTM. Punktmoln som framställs med egna mätningar från UASfotogrammetri och ett färdigt punktmoln från Laserdata NH. Målet med jämförelsen är att undersöka om det går att ersätta UAS-fotogrammetri med den kostnadseffektiva Laserdata NH i projektet för ett industriområde (Lödöse varvet) i Lilla Edets kommun, samt om det går att ersätta den överlag. Med hjälp av Agisoft Metashape programvaran framställdes det punktmolnet från mätning från UAS av modellen DJI Phantom 4 Advanced, sedan jämfördes den mot det färdiga punktmolnet från Laserdata NH i CloudCompare programmet. Resultatet på denna studie visar att det går att ersätta UAS-fotogrammetri mot Laserdata NH i just denna och andra liknande projekt som har samma syfte och viss bestämd noggrannhet då punktmolnen inte avviker signifikant från varandra. Medan det inte går att ersätta de mot varandra överlag, då UAS-fotogrammetri erhåller högre noggrannhet när det gäller framställning av ett punktmoln jämfört med vad Laserdata NH har för noggrannhet på sina mätningar<br>Generation of Digital Terrain Model (DTM) is an essential part in project planning in questions related to spatial planning. Basis for the DTM is the point cloud which obtains initial data from the measurement. DTM can be used in different areas, accepted quality level is depending on the assignment for which DTM is produced. UAS-photogrammetry is one of the methods which is used for DTM generation, but it is possible to produce DTM from point cloud originated from Laserdata NH. A DTM is a model representing entirely terrain surface, where the data used for its generation gathers from measuring of a certain object. The purpose of this study accomplished at Department of Engineering Science at University West was to compare two different methods for point cloud generation as a basis for DTM. First point cloud generated comes from own measurement with UAS-photogrammetry and second is a point cloud from acquired Laserdata NH. The goal of the comparison is to examine if it is possible to replace UAS-photogrammetry with the cost effective Laserdata NH in the project for the industrial area (Lödöse varvet) in Lilla Edet municipality, and if it is possible to replace it generally. With help of Agisoft Metashape software the point cloud from UAS-measurement with DJI Phantom 4 Advanced was generated and then compared to Laserdata NH point cloud in CloudCompare program. Result of this study is showing that it is possible to replace UAS-photogrammetry with Laserdata NH in this specific and others similar projects which have same purpose and certain decided precision since point clouds are not significantly deviating from each other. While it is not possible to replace them generally, as UAS-photogrammetry obtains higher precision concerning point cloud generation compared to accuracy that Laserdata NH has in its measurements.

The main aim of this master thesis is utilization of the laser scanning technology in the field of information modelling of historical objects (HBIM). The optimal workflow of creating the information model in the Autodesk Revit has been demonstrated. The workflow deals with the historical value of the object. For the purposes of this work, the object of the mausoleum Fabara has been selected. Furthermore, the master thesis focuses on the possibilities of publishing the resulting model.

The goal of this thesis is to scan part of the complex research center AdMaS using terrestrial laser scanner, from obtained data draw up a 3D terrain model and compare the height accuracy with conventional terrestrial measurement. The thesis is focused to software, which allow processing of point clouds and prepare the 3D model. The output of this work is the 3D terrain model and two transverse profiles for vertical comparison of two measurement methods.

Il versante sinistro delle Gole di Scascoli (BO) è caratterizzato da una marcata tendenza evolutiva per crollo e ribaltamento. Negli ultimi 25 anni si sono verificati eventi parossistici con volumi di roccia coinvolti rispettivamente di 7000 m3, 20000 m3 e 35000 m3. Il sito è di grande rilevanza a causa del forte fattore di rischio rappresentato per la strada di fondovalle ad esso adiacente. Il lavoro di tesi è stato finalizzato allo studio dei fenomeni di versante di una parete rocciosa inaccessibile nota in letteratura come “ex-Mammellone 1” mediante tecniche di telerilevamento quali TLS (Terrestrial Laser Scanning) e CRP (Close Range Photogrammetry) al fine affiancare il rilievo geomeccanico soggettivo dell’area svolto nel 2003 da ENSER Srl in seguito ai fenomeni di crollo del 2002. Lo sviluppo di tecnologie e metodi innovativi per l’analisi territoriale basata sull’impiego di UAV (Unmanned Aerial Vehicle, meglio noti come Droni), associata alle tecniche di fotogrammetria digitale costituisce un elemento di notevole ausilio nelle pratiche di rilevamento in campo di sicurezza e tempi di esecuzione. Il lavoro ha previsto una prima fase di rilevamento areo-fotogrammetrico mediante strumentazione professionale e amatoriale, a cui è seguita l’elaborazione dei rispettivi modelli. I diversi output sono stati confrontati dal punto di vista geomorfologico, geometrico, geomeccanico e di modellazione numerica di caduta massi. Dal lavoro è stato possibile indagare l’evoluzione morfologica del sito in esame negli ultimi 10 anni, confrontare diversi metodi di rilevamento e analisi dati, sperimentare la robustezza e ripetibilità geometrica del metodo fotogrammetrico per il rilievo di fronti rocciosi e mettere a punto un metodo semiautomatico di individuazione e analisi delle giaciture delle discontinuità.

In current forensic practice, there are few standards for outdoor crime scene documentation, despite the need for such documentation to be accurate and precise in order to preserve evidence. A potential solution to this is the implementation of image-based photogrammetry. Applied Structure from Motion (SfM) reconstructs models through image point comparisons. A 3D model is produced from a reference photoset that captures a 360-degree view of the subject and the software employs triangulation to match specific points, datums, across individual photos. The datums are arranged into a point-cloud that is then transformed into the final model. Modifying the point-cloud into a final product requires algorithms that adjust the points by building a textured mesh from them. One of the disadvantages of SfM is that the point-cloud can be “noisy,” meaning that the program is unable to distinguish the features of one datum from another due to similarities, creating coverage gaps within the meshed images. To compensate for this, the software can smooth portions of the model in a best-guess process during meshing. As commercial software does not disclose the adjustment algorithms, this documentation technique, while very useful in other disciplines that regularly apply SfM such as archaeology, would fail to meet the standards of the Daubert and Kumho criteria in a forensic setting. A potential solution to this problem is to use open-source software, which discloses the adjustment algorithms to the user. It was hypothesized that the output of open-sourced software solutions would as accurate as the models produced with commercial software and with total station mapping techniques. To evaluate this hypothesis, a series of mock outdoor crime scenes were documented using SfM and traditional mapping techniques. The scenes included larger surface scatter and small surface scatter scenes. The large surface scatter scenes contained a dispersed set of plastic human remains, and various objects that might reasonably be associated with a crime scene. Ten of these scenes were laid out in 10 x 10 m units in a New England forested environment, each grid with a slightly different composition, and then documented using an electronic total station, data logger and digital camera. The small surface scatter scenes consisted of a pig mandible placed in different environments across two days of data collection. The resulting models were built using PhotoScan by AgiSoft, the commercial software, and MicMac for Mac OSX as the open-source comparison software. Accuracy is only part of the concern however; the full utility of any one of the workflows is defined additionally by the overall cost-effectiveness (affordability and accessibility) and the visual quality of the final model. Accuracy was measured by the amount of variance in fixed-datum measurements that remained consistent across scenes, whereas visual quality of the photogrammetric models were determined by cloud comparison histograms, which allows for comparison of models between software types and across different days of data collection. Histograms were generated using CloudCompare. Not all models that were rendered were useable—90% of large surface scatter models and 87.5% of small surface scatter models were useable. While there was variance in the metric outputs between the total station and photogrammetric models, the average total variance in fixed-datum lengths for individual scenes was below 0.635 cm for six of the ten scenes. However, only one of the large surface scatter scenes produced measurement that were significantly different between the total station measurements and the software measurement. The maximum differences in measurement between the total station and software measurements were 0.0917 m (PhotoScan) and 0.178 m (MicMac). The minimum difference that was found for either software was 0.000 m, indicating exact measurement. The histograms for the large scatter scenes were comparable, with the commercial and open-source software-derived models having low standard deviations and mean distances between points. For the small surface scatter scenes, the histograms between software types varied depending on the environment and the lighting conditions on the day of data collection. Conditions such as light, ground foliage and topography affect model quality significantly, as well as the amount of available computing power. No such issues of losing objects or limitations of computing power were encountered when mapping by total station and processing the data in AutoCAD. This research shows that SfM has the potential to be a rapid, accurate and low-cost resource for forensic investigation. SfM methodology for outdoor crime scene documentation can be adapted to fit within evidentiary criteria through the use of open-source software and transparent processing, but there are limitations that must be taken into consideration.