UAV Photogrammetry for topographic monitoring of coastal areas

Coastal areas suffer degradation due to the action of the sea and other natural and human-induced causes.

Topographical changes in beaches and sand dunes need to be assessed, both after severe events and on a regular basis, to build models that can predict the evolution of these natural environments.

This is an important application for airborne Laser Imaging Detection and Ranging (LIDAR) and conventional photogrammetry is also being used for regular monitoring programs of sensitive coastal areas.

This paper analyses the use of UAVs (Unmanned Aerial Vehicles) to map and monitor sand dunes and beaches. A very light plane equipped with a very cheap, non-metric camera was used to acquire images with ground resolutions better than 5 cm.

The Agisoft Photoscan software was used to orientate the images, extract point clouds, build a digital surface model and produce orthoimage mosaics. The processing, which includes automatic aerial triangulation with camera calibration and subsequent model generation, was mostly automated.

To achieve the best positional accuracy for the whole process, signalised ground control points were surveyed with a differential GPS (Ground Positioning System) receiver. Two very sensitive test areas on the Portuguese northwest coast were analysed.

Detailed DSMs were obtained with 10 cm grid spacing and vertical accuracy (RMS) ranging from 3.5 to 5.0 cm, which is very similar to the image ground resolution (3.2–4.5 cm). Where possible to assess, the planimetric accuracy of the orthoimage mosaics was found to be subpixel.

Within the regular coastal monitoring programme being carried out in the region, UAVs can replace many of the conventional flights, with considerable gains in the cost of the data acquisition and without any loss in the quality of topographic and aerial imagery data.

Read more:

https://www.researchgate.net/publication/274645398_UAV_photogrammetry_for_topographic_monitoring_of_coastal_areas

UAVs for 3D mapping applications

Unmanned Aerial Vehicle (UAV) platforms are nowadays a valuable source of data for inspection, surveillance, mapping and 3D modeling issues.

As UAVs can be considered as a low cost alternative to the classical manned aerial photogrammetry, new applications in the short- and close-range domain are introduced.

Rotary or fixed wing UAVs, capable of performing the photogrammetric data acquisition with amateur or SLR digital cameras, can fly in manual, semi automated and autonomous modes.

Following a typical photogrammetric workflow, 3D results like Digital Surface or Terrain Models (DTM/DSM), contours, textured 3D models, vector information, etc. can be produced, even on large areas.

This paper explore the use of UAV for Geomatics applications, giving an interesting overview of different UAV platforms and case studies.

https://www.researchgate.net/profile/Fabio_Remondino/publication/260529522_UAV_for_3D_mapping_applications_A_review/links/00b7d532f0e4da131e000000/UAV-for-3D-mapping-applications-A-review.pdf

Low Cost 3D Mapping Using a Commercial Drone/UAV: Application in Structural Geology

This presentation describes an experience of mapping a geological structure with a commercial UAV (Unmanned Aerial Vehicle).

Being based in Venezuela, an appropriate area for the acquisition was identified in the Andes Cordillera where a major strike slip fault (Boconó Fault) intersects geomorphic features modeled by the latest glaciation.

This fault is a major tectonic lineament oriented SW-NE, extending more than 300 km along the Venezuelan Andes and accommodating a dextral slip on the order of 1 cm/year.

This motion has displaced various landscape features that cross the fault, in particularly the "Los Zerpa" moraine system, located a few kilometers NE of the locality "Apartaderos".

The moraine formed during the last glaciation that ended 10,000 years ago; its northern tip crosses the Boconó Fault and is displaced 100 m towards the NE; this corresponds to a rate of 1 cm/year, which is consistent with GPS measurements. 

http://www.searchanddiscovery.com/documents/2017/42054rocca/ndx_rocca.pdf

Change Detection in Aerial Images Using Three-Dimensional Feature Maps

Interest in aerial image analysis has increased owing to recent developments in and availability of aerial imaging technologies, like UAVs (Unmanned aerial vehicles), as well as a growing need for autonomous surveillance systems.

Variant illumination, intensity noise, and different viewpoints are among the main challenges to overcome in order to determine changes in aerial images. In this paper, it is presented a robust method for change detection in aerial images.

To accomplish this, the method extracts three-dimensional (3D) features for segmentation of objects above a defined reference surface at each instant. The acquired 3D feature maps, with two measurements, are then used to determine changes in a scene over time.

In addition, the important parameters that affect measurement, such as the camera’s sampling rate, image resolution, the height of the drone, and the pixel’s height information, are investigated through a mathematical model. To exhibit its applicability, the proposed method has been evaluated on aerial images of various real-world locations and the results are promising.

The performance indicates the robustness of the method in addressing the problems of conventional change detection methods, such as intensity differences and shadows.

(Read more)

The 20th Attack Squadron locates and kill a terrorist command

The demand for UAVs to conduct armed overwatch missions to help protect United States forces, as well as their allies and partners, isn't going away, but exact the opposite: For the foreseeable future, the Reapers will continue to provide this invaluable service for American troops around the world, as you can see in a recently released video that includes a unique clip that an MQ-9 Reaper captured of militants firing a rocket-propelled grenade at a C-130 Hercules airlifter that was performing an air drop of cargo at relatively low altitude.

In the full video, the UAV's pilot and sensor operator, who later struck those hostile forces, also offer an interesting behind-the-scenes look at how the unmanned aircraft perform these kinds of armed overwatch missions. The Air Force's 432nd Wing at Creech Air Force Base in Nevada, one of the service's premier UAV units, posted the video on YouTube on Apr. 6, 2020. The pilot, 1st Lieutenant Russel, and the sensor operator, Airman First Class Ashley, both assigned to the 20th Attack Squadron, which itself is assigned to the 432nd, but is based at Whiteman Air Force Base in Missouri, describe the event.

Guía de diseño para Fabricación Aditiva

Desde Integral 3D Printing tienen el placer de invitarnos a la primera masterclass de Fabricación Aditiva, que tendrá lugar durante los próximos 23 y 28 de enero en País Vasco (Elgoibar) y Madrid, respectivamente.

Durante la masterclass, no solo aprenderemos cómo diseñar y optimizar nuestros diseños para su posterior impresión en 3D, sino que tendremos la oportunidad de conocer, de la mano del propio fabricante, la tecnología de HP Multi Jet Fusion aplicada a algunos casos de éxito.

Aprovechemos esta oportunidad para aprender de los mejores expertos y conocer en directo las últimas novedades de la tecnología de fabricación aditiva con más potencial en el sector. No dejemos pasar esta oportunidad y explotemos al máximo el rendimiento de la fabricación aditiva en la nueva era de la producción digital gracias a Integral 3D Printing y HP.

Más información:

https://integral3dprinting.com/ferias-eventos/masterclass-guia-diseno-para-la-fabricacion-aditiva-en-la-nueva-era-de-produccion-digital/#contacto

¿Quieres reducir peso en tus UAVs? Descubre cómo

HP 3D Printing ha organizado un Webinar para explicar cómo la fabricación aditiva puede mejorar los procesos de fabricación a lo largo del ciclo de vida del producto. Naturalmente, HP se centrará en su tecnología Multi Jet Fusion y creo, por lo que conozco esa tecnología y por lo que conozco del resto de tecnologías de Manufactura Aditiva, que puede ser muy interesante para fabricar UAVs más ligeros mediante la sustitución de piezas metálicas por piezas de plástico: Esa reducción de peso traerá como consecuencias un menor consumo de combustible, así como un incremento de la velocidad máxima y el alcance.

Otra de las ventajas que veo super interesante para los fabricantes de UAVs, estriba en la alta productividad de esta tecnología, que supera con creces al resto de tecnologías competidoras. ¿Más ventajas? El diseño absolutamente libre: Si queremos producir UAVs más pequeños, más ligeros, más veloces y con mayor carga de pago, forzosamente deberemos rediseñar sus componentes cuando no el conjunto completo. Pero fabricarlos puede ser luego imposible por las limitaciones que impone la fabricación tradicional mediante CNC. Sin embargo, con la manufactura aditiva ese problema desaparece, y más aún con la tecnología de HP gracias al elevado nivel de isotropia que presentan las piezas impresas mediante la tecnología Multi Jet Fusion.

En definitiva, creo recomendable apuntarse a este evento: descubrirás los beneficios de la tecnología HP Multi Jet Fusion y conocerás casos de éxito de OEMs que están reinventando la forma en la que se fabrican sus productos. Por tanto, si deseas reducir el peso de tus UAVs no te pierdas esta oportunidad única de conocer en profundidad las posibilidades de esta tecnología sin precedentes.

Más información e inscripciones:

https://hp.zoom.us/webinar/register/2015650146868/WN_Zh7KVtKZTuqFSX-KOxG04g?utm_source=BenchmarkEmail&utm_campaign=Webinar_HP_diciembre_2019&utm_medium=email