Home / Explanation / Combining 3D-CT scanner and photogrammetry

Estimated reading time: mins

Combining 3D-CT scanner and photogrammetry

Last updated: 10.06.2020
Explanation
Swann Rack

Fusion of Photogrammetry and 3D CT Scanning 05:10

We combine the advantages of photogrammetry and 3D CT scanning (computed tomography) to create a highly accurate color 3D scan. Photogrammetry provides the best possible color information, while computed tomography allows us to 3D-scan the object with unparalleled accuracy. Subsequently, the 3D scan data from both techniques are merged.

What is Photogrammetry? And What is a 3D CT?

Photogrammetry and a 3D CT are two different 3D scanning techniques. In photogrammetry, the 3D
scan is calculated from photos. The object is photographed from all sides, and software generates a
3D model.

3D CT scan animation of an x-rayed shoe — Peter Hornberger / Fraunhofer IIS 3D CT X-ray sectional image animation

Inside the 3D CT Scanner (also known as 3D computed tomography), X-ray sectional images are
taken from all sides of the object, and the 3D scan is calculated from these images.

Walk in 3D CT scanner from Fraunhofer IIS — Swann Rack / Holocreators Walk-in 3D CT (computed tomography 3D scanner) at the Fraunhofer IIS.

Fusion of Both Techniques

Both photogrammetry and 3D CT scanning have their advantages and disadvantages. With the fusion
of both techniques, we want to combine the strengths of both systems.

The biggest advantage of photogrammetry is that it creates a colored 3D model
The biggest advantage of 3D CT scanning is that it measures very accurately and that it also captures the interior of an object

By fusing of both techniques, we get a highly accurate colored 3D scan.

Photogrammetry camera rig inside 3D CT scanner — Swann Rack / Holocreators Inside the walk-in 3D CT—a photogrammetry set-up consisting of DSLR cameras and lights

Research Project Cooperation

For this research project, we cooperated with the Institute of Technology Deggendorf and the
research institute Fraunhofer IIS. These institutes research the application possibilities of industrial
computed tomography. As a first feasibility study, we 3D scanned a shoe.

3D CT-scanning software from Fraunhofer IIS — Swann Rack / Holocreators 3D CT software that controls the computed tomography 3D scanner

How Does the 3D Scan Work?

The shoe is placed on a turntable and photographed by three cameras. After a triple set of pictures
has been taken, the turntable rotates a few degrees further, and the cameras take another set of
pictures. The result is a set of 72 images from many different perspectives, from which a 3D model
can be calculated using photogrammetric software. For the next step, the 3D CT scanner is switched
on, and the shoe is x-rayed. Both 3D scanning techniques are performed one after the other and
without moving the shoe.

3D CT scan of Adidas shoe without color — Swann Rack / Holocreators 3D CT scan of a sports shoe without color

Merging Two 3D Scans

The recording process results in two 3D scans. One with color, created by photogrammetry and one
created using 3D computed tomography. Both data sets are merged. The color information of the
photogrammetric 3D scan is projected over the 3D CT scan. This fusion results in a highly accurate
3D scan with color.

Fusion of 3D CT scan and photogrammetry to create a color 3D model of Adidas shoe — Swann Rack / Holocreators Fusion of 3D CT and Photogrammetry produces a highly accurate 3D scan of the sports shoe with
color

Project Data for Download

We have prepared the unprocessed 3D CT scan, the photogrammetry photos and the finished 3D
scan for you to download.

Conclusion

The fusion of photogrammetry and 3D CT is ideal for creating highly accurate 3D scans of an object
with color. If we find a way to automate the recording process, as well as the data processing, this
3D scanning technique could be relevant for 3D product photography.

Do you need a 3D CT scan with color?

Holocreators offers professional 3D-scanning and reverse engineering services. We create 3D scans
with computed tomography (3D CT) and photogrammetry and thus can offer your highly accurate 3D
scans in color. We would love to help you with your project. Please call us at +49
40 481133 or send an email info@holocreators.com

Last updated: 10.06.2020
Explanation

Author: Swann Rack

Swann has been enthusiastic about everything 3D for many years. His roots lie in analog holography, which brought him to digital 3D-modeling in 2011.

The rapid progress of various 3D-scanning techniques fascinated himso much thathe founded Holocreators together with his brother Miro Rack in 2015.

Ready to get started?

Name*
First
Email*
Phone
Your message
Upload an image or drawing
JPG, PDF, or PNG max 100 MB
Drop files here or

Accepted file types: jpg, png, pdf, jpeg, Max. file size: 100 MB.
Consent*
You agree that your information from this contact form will be saved and processed to respond to your request. Holocreator's privacy policy and Terms and Conditions apply.*

How to 3D-scan people or animals?

With the help of specialized 3D scanners, you can 3D-scan people and animals. This allows you to create 3D models that can be 3D-printed or used for 3D animation. We'll show you three different devices that make such 3D scans possible.

Estimated reading time: mins

Last updated: 11.11.2020
Explanation

What is Kitbashing?

Kitbashing is associated with model making. It is composed of the words "Kit" and "Bashing". “Kit” refers to "model kit". So, when a model maker is "kitbashing", he blends parts from different model kits. Similar to a collage. The model maker combines several individual models into an entirely new model.

Estimated reading time: mins

Last updated: 06.08.2020
Explanation

What Types of 3D Model Databases Are Available?

We have compiled a selection of 3D model databases. You can download 3D models and then edit them in a 3D program or 3D print them. There are databases with free 3D models and those that sell them.

Estimated reading time: mins

Last updated: 05.08.2020
Explanation

What is Reverse Engineering? (Converting a 3D-Scan to CAD)

Reverse engineering is required whenever a 3D scan (STL format) needs to be converted into a CAD model (STEP format). We will give you a brief overview of three different reverse engineering techniques.

Estimated reading time: mins

Last updated: 02.08.2020
Explanation

What is the difference between NURBs model and a mesh?

A NURBS model consists of points connected by curves. A polygon mesh consists of thousands or millions of small triangles. CAD surface models are usually created using NURBS surfaces, while 3D scans are typically exported as a polygon mesh. The conversion from a polygon mesh to a NURBS model is called "reverse engineering".

Estimated reading time: mins

Last updated: 01.08.2020
Explanation

Reverse engineering and error propagation

Reverse engineering enables us to create a copy of an object. For this purpose, the part is 3Dscanned, then the 3D scan data is converted into a CAD format, and finally, the part is manufactured. All these steps result in noticeable deviations. If an error adds up over multiple steps, then we call this error propagation.