Fusion of Photogrammetry and LiDAR

In the first part of this 2-part series, we outlined the benefits and drawbacks of using either photogrammetry or LiDAR to generate a digital elevation model (DEM), with a focus on how the two methods perform in different environments.

In this second article, we will discuss how photogrammetry and LiDAR can be used in tandem to improve the solution as a whole.

Benefits and Drawbacks


Photogrammetry and LiDAR are powerful tools that produce excellent results when used correctly.
Below is a recap of part 1 of this newsletter, listing the individual pros and cons for LiDAR and Photogrammetry.

LiDAR Photogrammetry
Advantages - Vegetation canopy penetration
- High vertical accuracy
- Rich scene information
- High horizontal accuracy
Disadvantages - No scene information
- Lower point density
- Vegetation occlusion
- Image overlap and matching required
- Lower vertical accuracy


Sensor Fusion, the Stronger Solution

In a movie, the right music or sounds can drastically alter the feeling of a scene – the audio complements the video, producing a better result. In the same way that audio and video together make a better scene, LiDAR and Photogrammetry can be fused to produce a better solution.


With the combination of LiDAR and Photogrammetry, information can be extracted from the datasets based on the individual strengths of each method. The accuracy and detail of the LiDAR data can be complemented with the context and point density of the photogrammetry, resulting in a single 3D dataset encompassing the best of both worlds.

This ideal 3D dataset can now be used to extract valuable information for your project needs, for example, automated 3D building models, environmental analysis based on vegetation health and structure, 3D visualizations, and so many more.

Summary

Combining both LiDAR and photogrammetry tools negates the majority of drawbacks for each method alone. The result is a superior surface or 3D model that is accurate, and rich in colour scene information. The combination of OGL Engineering's LiDAR sensor (Leica ALS70) and aerial camera (Leica RCD30) does not introduce significant complexity to processing, and has proven results that can add value to your project.