What is photogrammetry and how can it help with 3D scanning?

Have you ever scanned a sculpture or large object and the measurement results were a disaster? Scanning large objects can be challenging due to errors that accumulate after a certain measurement distance. How can we eliminate errors? Integrating photogrammetry into 3D scanning. Therefore, we can increase the speed and accuracy of data collection for the 3D modeling process.

How can photogrammetry be used in 3D scanning?

The 3D scanner uses lasers to identify the geometry of an object. Once the points are captured, a dense point cloud is generated which can create a 3D model. Most 3D scanners in stores are capable of scanning objects within a 1m radius, but it would be difficult to scan large objects such as : wind turbines, airplanes or buildings. This is where photogrammetry comes in.

When using photogrammetry, the first step is to use reflective markers on the surface of objects and encoded targets around them. A scalar bar is also needed to serve as a reference. Photos are then taken from different angles, making sure to get overlapping shots.

These images will help in the overall construction of the 3D geometry of the object. Surface details of the object can be captured with the 3D scanner. With full-frame and high-resolution cameras, the photogrammetry system can provide high-quality results. Thanks to its large shooting area and precise algorithm, it can reduce connection errors accumulated over long distances.

How can Scantech help? Prin the partner Soh 3D4ALL!

Which offers you: «MSCAN photogrammetry system» for scanning large objects with high demands on measurement accuracy and repeatability. “MSCAN photogrammetry system” Perhaps Work alone or can work with portable 3D scanners to achieve volumetric accuracy up to 0.015 mm/m.

To take photogrammetry to another level, Scantech offers the Kscan composite 3D scanner that combines infrared scanning, blue laser and photogrammetry in a single device. It will provide repeatable scan results with high precision details. When it comes to measurements it is suitable for both large objects and small objects.

Here is an example of the SCAN 3D scanner helping to inspect a planetary gear for a wind turbine. The diameter of this type of gear is generally more than 1 meter and weighs more than 1 ton. Engineers can get all the details of the part through 3D measurements, using «KSCAN-Magic 3D scanner” cu built-in photogrammetry.

Conclusion

The scenario described—scanning a large object where measurement errors accumulate with distance—highlights a common challenge in large-scale 3D digitization. The solution lies in the strategic integration of photogrammetry into the 3D scanning workflow. This hybrid approach effectively eliminates accumulating errors by using the photogrammetric data to create a high-accuracy reference system.

Here is how the integration works and translates into benefits:

1. Error Elimination: Photogrammetry (using a series of high-resolution photographs to calculate 3D points) creates a highly accurate, global coordinate system based on geometric constraints. By placing coded or non-coded targets on the large object and precisely measuring their positions using photogrammetry, the system establishes a fixed, reliable reference frame. The 3D scanner’s local data (which is prone to drift errors) is then mathematically constrained and corrected to fit this rigid, accurate reference frame. This prevents the small, unavoidable measurement errors from compounding over the long distances of the object.

2. Increased Speed: Photogrammetry quickly captures the entire object’s global geometry, reducing the time the 3D scanner needs to spend acquiring overlapping data simply for registration purposes.

3. Increased Accuracy: The process yields a more globally precise dataset because the 3D point cloud is anchored to the millimeter-level accuracy of the photogrammetric reference system, ensuring the final 3D model maintains high fidelity across its entire length.

This integration transforms the data collection process, delivering the necessary speed and accuracy for high-quality 3D modeling of massive or complex objects like sculptures.