We're sorry but this page doesn't work properly without JavaScript enabled. Please enable it to continue.
Feedback
00:00

Formal Metadata

Title
Photogrammetrische Messmethoden
Alternative Title
Photogrammetric Measuring Methods
Author
Contributors
License
CC Attribution 4.0 International:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
Identifiers
IWF SignatureC 13225
Publisher
Release Date
Language
Other Version
Producer
Production Year2008

Technical Metadata

IWF Technical DataVideo-Clip ; F, 5 min

Content Metadata

Subject Area
Genre
Abstract
German
German
Optische Messverfahren in den physikalischen Modellen der BAW bringen qualitativ und quantitativ hochwertige Daten. Mit dem 2-D-Partikel-Trecking-Velocimetrie Verfahren wird die Oberflächengeschwindigkeit mit einer Kamera erfasst. 3 Kameras erfassen bei 3-D-Partikel-Tracking-Velocimetrie die Wasserspiegellagen und die Oberflächengeschwindigkeit im Modell dreidimensional. Drei Kameras nehmen auch photogrammetrisch durch das Wasser hindurch die Geometrie und Veränderung der Flusssohle während des Versuchs auf. Die Daten fließen in numerische Modelle ein, mit denen auch weitergehende fahrdynamische Analysen durchgeführt werden..
English
English
Optical measuring methods applied the physical models of the BAW yield high quality and high quantity data. Using 2D particle tracking velocimetry, one camera records the velocity of the water surface. Using the 3D particle tracking velocimetry, three cameras are recording in three dimensions the water level and the surface velocity in the model at the same time. Three cameras also measure photogrammetrically the geometry and the changes of the river bed through the water during the ongoing experiment. Data are used in numerical models with which further dynamic analysis is performed.
Keywords
German
German
English
English
IWF Classification
German
German
English
English
BauxitbergbauMachineVolumetric flow rateOpticsModel buildingDisc brake
Disc brake
Volumetric flow rateWater vapor
Model buildingVolumetric flow rateModel buildingWater vaporPlane (tool)Reference workStream bedTracing paperRailroad
Water vapor
AmpouleVolumetric flow rateWater vaporFahrgeschwindigkeit
PortalkranModel buildingAircraft engineering
Reference work
CaliberComputer animation
Angle of attack
Reference workComputer animation
Model buildingPattern (sewing)Lecture/Conference
FaltenbildungSatelliteStream bedModel buildingTypesettingComputer animation
SeeschiffComputer animationDiagram
Reamer
Transcript: English(auto-generated)
The Federal Waterways Engineering and Research Institute in Karlsruhe, the BAW, conducts research in its laboratories using large physical models. Optical measuring methods are applied to yield high quality and high quantity data. Great precision is essential.
In the model of the Obernau-Wir near Aschaffenburg, the flow behavior of the river mine is being examined at various water levels. A machine specially designed in the BAW dispenses white polypropylene discs
at programmable frequency and controllable quantities. These traces, as they're called, precisely follow the flow on the water surface. They're carried along by the current and make it clearly visible. A fixed camera records their course.
From the data gathered, a computer then evaluates the flow behavior. The technique is known as two-dimensional particle tracking velocimetry, PTV for short, which records surface speed on camera. The four light points marked are the precisely calculated reference points.
For a one-camera measuring system, all the points must be at the same level, floating on the surface of the water. This solid bed half model of the river Elbe near Schoenberg is to measure currents in the groin fields.
Reference points again provide orientation and correlation. All the points are different. They each have their own circular barcode. For the three-camera system used here, the points don't have to be in the same measuring plane. The traces make the flow behavior in a groin field visible,
shown here in time-lapse. The groins here have cut-out sections, which are designed to change flow behavior. The traces are filmed by three cameras
and can therefore be evaluated three-dimensionally. The water level, the position of the traces, and their speed in the flow can be ascertained at one and the same time. The computer evaluation can then depict the flow behavior in the groin field.
Here we see the velocities and here the water levels. This measuring gantry above a model of the river Oder can be maneuvered to any point in the model.
Before it's used on the model, the three-dimensional measuring system has to be spatially calibrated. The reference points are fixed at different heights for this. The configuration of the three cameras to one another on the rigid frame is measured.
This has to remain constant during the whole measuring procedure. Here, too, the features and orientation of all the components in the system, such as sensors and lenses, must be precisely determined before every measurement. With the calibration completed, measuring can begin.
The three cameras take pictures of the surface from different angles. The reference points enable the measured data to be collated. From above, a grid pattern is projected down onto the surface of the model.
The spatial position of every point on the grid can now be ascertained via triangulation. An expanded version of this system also ascertains the mean water level in the measuring field at the same time. The optical paths of the video cameras are calculated.
Then the underwater changes on the riverbed can also be measured during the test. This three-dimensional terrain model consists of a total of 4,000 individual data sets taken every 10 seconds over a period of 11 hours.
The different colors show the different levels of the riverbed. Red represents higher areas, green deeper levels. Using numerical models, computed on the basis of the data gained from the physical model, the course of a ship traveling upstream can be simulated. The ship seeks the best course for avoiding shallows.
A number of variants are examined. The dynamic simulation process, also developed by the BAW, takes account of the physical characteristics of the ship.