The drones (UAV) and photogrammetry.

jlmol7 (47)in #geopolis • 8 years ago (edited)

Hi guys, with the advances in technology and the devices that are created from this, we are getting closer and closer to achieving new discoveries that 20 years ago we did not think possible. This time I will talk a little about the applications of UAV in the area of photogrammetry.
The use of applications related to images in UAV photogrammetry are increasing very rapidly. This does not surprise us because the use of UAV with GPS sensors incorporated for aerial surveys turns out to be very profitable, unlike the hiring of an aircraft with photogrammetry equipment. Which is how it is done in a conventional way.

Photogrammetry is the science of making measurements from photographs. The output of photogrammetry is typically a map, a drawing or a 3D model of some real-world object or land mass.

Photogrammetry

One characteristic to highlight is the versatility of the aerial platform when adapting the sensor or camera according to the particular needs of the project to be executed, guaranteeing at all times the high spatial resolution of the images due to the low height at which they can fly.
These technologies represent an innovative alternative for the capture of images of the terrestrial surface destined to the cartographic confection in their different modalities, inasmuch as they are more accessible and of easy handling.

UAV for photogrammetry

There are many reasons why drones with the passage of time have become essential for jobs related to the field of engineering, as I mentioned before, one of the things that most like these wonderful teams is how affordable they are economically speaking, besides that they reduce the time of execution of the projects up to 5 times unlike in the conventional way.

Our customers have shown that multi-day traditional surveying projects can be cut down to multi-hour drone enabled projects.

A case study in Morocco details game-changing capabilities by UAS in orthophotography and aerial mapping. A series of studies conducted by comparing UAV data collection with conventional satellite imagery found that the advantage of UAS brought image resolution from over a meter to less than ten centimeters. With ground control points, the precision of the images improved proportionally.

Modeling by photogrammetry

There are really many advantages around the collection of data for cartographic purposes and several areas that are closely related to photogrammetry, which have not only been used to study the surface of the earth from relatively low altitudes, but also the NASA scientists decided go further and take these studies to unimaginable heights and with the support of Geographic Information Systems expand the area of study and link it to new branches of science and engineering.

The advantages drones provide in data collection make them not only perfect for observing the surface of the earth, but also the atmosphere. NASA has already put their drone, Global Hawk, to use looking for hurricane activity. The imagery collected by drones like this one becomes a powerful resource once fed into GIS.

Global Hawk

The benefits of using UAVs for photogrammetric surveying are that their speed, position, and stabilisation can be controlled extremely accurately, so sequential, blur-free aerial photographs of a site can easily be taken, which can then be used to create 3D point clouds, digital terrain models, contour maps, or be merged into a 2D or 3D orthomosaic image.

For the design of 3D maps based on aerial photogrammetry, the most important thing is to adapt the camera or sensor that you want to use and it is usually pointed vertically towards the ground. A series of continuous photographs are captured with each other, with an overlap level of 80 to 90% (the greater the overlap between the images, the geometrical distortions in the mosaic are eliminated), since these devices move through a flight line programmed and previously defined. For this reason it is essential that the UAV have built-in GPS sensors.