What is Laser scanning?

Laser scanners capture millions of points by using laser time-of-flight or phase-shift to accurately measure distances. Millions of measurements are then transformed into a dense and highly accurate 3D point cloud. Think of it as capturing the “geometry” of a site with extreme precision. For a more in-depth guide, please see What Is Point Cloud Scanning?

What is Photogrammetry?

High resolution handheld or drone cameras capture hundreds, sometimes thousands of overlapping 2D photographs from many angles and transforms them into a 3D mesh of the space. Think of it as capturing the “appearance” of a site and deriving geometry from it. For a more in-depth guide, please see What Is Photogrammetry?

Laser Scanning: What is it good for?

The biggest advantage of laser scanning is the extremely high accuracy. It provides millimetre level accurate data making it ideal for structural analysis, MEP clash detection and other projects which require near perfect measurements. Laser scanners take direct measurements meaning it is almost completely immune to errors from lighting, surface patterns or camera. Laser scanners also work perfectly without any light; this makes them ideal for work in places like Mines or Tunnels. You can see real examples of our work in the Wieliczka Salt Mine and tunnel scanning projects in Sweden.

Photogrammetry: What is it good for?

The biggest advantage of photogrammetry is the low cost of entry. A high-quality professional drone and a high-resolution camera are significantly cheaper than a terrestrial laser scanner. If accuracy is not what you are after, even a smartphone can be used to collect the necessary 2D photographs that can then be processed into a 3D Mesh. What photogrammetry loses in accuracy, it gains in photorealism. This is invaluable for condition assessments, facade studies, architectural documentation, and creating visually compelling deliverables for clients. You can see cracks, material types, and colours directly. Photographs collected by drone can also record data in places that a laser scanner could not.

What to choose: Laser Scanning or Photogrammetry

What is the required deliverable accuracy?

For millimetre accuracy, Laser Scanning is the optimal choice – The direct measurements capture precise geometry ideal for structural analysis or clash detection. For centimetre accuracy, Photogrammetry is the way to go, achieving visually rich mesh models, perfect for condition reports and visualisations.

What is the environment?

Choose Laser Scanning for complex indoor spaces with shiny surfaces, glass, or low light. This method is far less susceptible to reflections or darkness. Drone photogrammetry, on the other hand, excels at large external topographies covering big areas of land. For close-range photorealistic detail, handheld photogrammetry is best.

What is the budget?

For high budgets, Laser Scanning delivers unmatched precision but requires expensive equipment and skilled operators. For limited budgets, Photogrammetry is the better choice. Consumer drones, cameras or even smartphones can be used to make quality 3D capture accessible at a fraction of the cost.

There is always the right tool for a job, and having the knowledge and expertise allows you to make the optimal choice. Analysing the most important factors for your project is key; Accuracy, cost, data file size and site conditions all need to be considered before making the choice between Laser Scanning or Photogrammetry. But there is a third option, the hybrid approach.

The Hybrid Approach

At 3Deling, we use a mixture of Laser Scanning, handheld and drone Photogrammetry, to get the best results for our clients. Point cloud data gathered by way of laser scanning can be processed with mesh date gathered by way of photogrammetry. This is the best of both worlds. It gives you the ability for extremely high accuracy in places where its required, with a photorealistic mesh. Years of experience using these methods give us the ability to advise you on what is the best fit for your project.

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