Gewindestangen mit Messmarken für Photogrammetrische 3D-Veremssung

Photogrammetric measurement of screw sleeves

To set up a machine safely on a foundation, so-called fastening anchors must be embedded in the ground before installation at the place of installation. It often happens that the dimensions and tolerances specified by the construction are not observed when the fastening anchors are let in. This can lead to distortion during installation work, as the fixing holes on the machine side do not fit into the specified hole pattern on the foundation.

Customer Requirement:

Our customer wants to set up his new machine within one day. In order to avoid any delay in the installation process, our customer wants the pose (position and orientation) of the 24 screw sleeves to be measured with an accuracy of ±0.5mm / ±2mm/m.

The data should be output in a CAD format (in this case STEP) for further processing.

Measuring task:

When selecting the measuring system, we had decided to use the photogrammetry system, because due to its mobility and robustness, high accuracies are achieved even under changing weather conditions in the open air. The set-up time with the time-consuming application of the measuring marks is usually an important temporal factor in photogrammetry, but with the very few measuring points it had no decisive influence on the measuring time.

Because of the daylight with the changing exposure conditions, several test images were taken beforehand to adjust the camera settings with regard to brightness and image sharpness.

The measurement was carried out with a total of 35 individual images from different perspectives. In order to obtain the best possible cutting angles, the camera is held at different heights.

After the images were taken, they were imported into an evaluation software. Here the 2D image coordinates of all measuring points in the image were measured. Using an approximation method, identical measuring points were assigned and the coordinates calculated in 3D.

The coordinates of the measuring points are then transferred from the AICON software into a graphics software for graphical control and point assignment.

Result:

For a better illustration of the pose of the individual screw sleeves, the position and inclination of the sleeves in the concrete foundation were calculated based on the thread dimensions and passed on to the customer as a STEP file with the nominal sleeve diameter.

The customer incorporated the CAD data of the actual situation into his design program and adapted the machine mountings on this basis.

The request of our customer for a fast and thus cost-saving measurement could be easily realized with our mobile measuring system.

 

Do you have any questions? - Please do not hesitate to contact us!