Digital twins - Photogrammetry

3D CityScapes is constantly looking to increase the complexity and realism of our digital twins. Using photogrammetry, we provide our clients even more lifelike representations, faster designs, and impeccable interactions/visualizations.

What is Photogrammetry?

Photogrammetry is a field of science and technology responsible for detecting information about an object from a series of images. To produce these high quality 3D representations, we create three levels where designs fall into, using machine-learning and algorithms.

  1. Human made objects (highest quality of detail)
  2. Machine assisted object (medium quality detail)
  3. Machine made objects (lowest quality of detail)

Photogrammetry is a crucial step in achieving  levels 2 and 3. 

Why Photogrammetry?

Photogrammetry provides the basis for producing exceptional digital twins of cities, with minimal human input and at a fraction of the cost. This gives us and our clients a competitive edge when it comes to production, management and delivery. 

How is it done?

3D CityScapes takes a traditional and machine learning approach. In a traditional photogrammetry project, there are 4 stages:

  1. Image placement
  2. Image comprehension
  3. Image triangulation
  4. Model creation

1. Image Placement

First we identify where on a 3 dimensional map the images should be placed. By identifying which cameras see the same object, we can determine the position of the cameras.

2. Image INTERPRETATION

Once we identify where the cameras are positioned, we proceed to camera triangulation. Most cameras have a hemisphere lens as shown below:

This hemisphere distorts the image changing the distance between pixels at different areas of the image. Once we calculate the distances between each pixel, we then start to measure the distance to each point in the 3D space from the cameras.

3. IMAGE TRIANGULATION

Once each point in the image has been assigned a 3D location, we match these points between 2 or more images. This creates a virtual point cloud, which then allows us to convert it into a mesh. Below is an example of this mesh without texture:

4. CREATION OF 3D MODEL

The final step is to add in colour and texture. Below is an example of one of the texture files: 

 

Once the texture file is applied to the mesh, our 3D artists will make additional adjustments to the model, ready to be loaded on to our application. 

Here is a level 3 city design, built using this approach:

Book a free online demo to learn more about how we can bring your vision to life.

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