Photogrammetry with drones

Drone photogrammetry is a technique that uses drones with cameras or other sensors to collect aerial images from different angles and heights.

Remember that if you purchase a drone with a device that captures images and you want to do photogrammetry, you are (almost certainly) required by law to register as a drone operator. Consult before commencing your aviation operation.

What is photogrammetry?

Drone photogrammetry is a technique based on the principle of triangulation, which uses between 125 and 150 photographs (to achieve good results) taken from different points of view to measure and represent 3D objects made with UAS.

The different types of drones, or unmanned aerial vehicles (UAVs), have opened up an incredibly wide field and new possibilities for accurate three-dimensional modelling.

This technique of capturing geospatial data has undergone a significant transformation with the advance of drone technology, which allows images to be captured from different positions and heights, obtaining, consequently, a greater amount of information.

These images are then processed to create accurate and detailed three-dimensional (3D) models in order to study and precisely define an area or the shape, dimensions and spatial position of an object or motif.

Drones for 3D photogrammetries

Nowadays with any drone over 300€, thanks to powerful software and applying the right technique, you will get very good results.

However, if your goal is to achieve professional photogrammetry with drones, I suggest drones like the Mavic 3 Enterprise and the high-end drones with RTK if you need to achieve more precise photogrammetry and more accurate measurements.

Having a GPS on the ground to give you supporting geolocations could be another good option.

It is important to do thorough research and compare the features of each drone to ensure you purchase the right device for your drone photogrammetry project.

(Probably) The best drones for photogrammetry

I don’t know if these drones are the best drones for photogrammetry, but I am sure that with any of them you will be able to achieve more than good results.

The best drone for drone photogrammetry will depend on your needs, budget and the requirements of the project. What we can do is to enhance the quality of the final product by installing a higher quality camera.

• DJI Phantom 4 RTK: This drone is one of the most widely used for photogrammetry and mapping. It features a high-precision RTK positioning system, a 20 MP camera with 4K and 60fps recording. It has an omni-directional system to avoid obstacles. It has advanced autonomous flight functions, such as ActiveTrack and Tapfly, and a battery life of about 30 minutes.
• DJI Mini 4 PRO: The DJI Mini 4 PRO is, to date, a drone that can be flown without a licence within cities and towns. It is foldable and ultra-lightweight, and offers exceptional image quality with its 48MP camera and 4K recording. With a flight range of up to 34 minutes.. It has the possibility of using waypoints, just like the DJI Air 3, which are so useful (in professional work) when it comes to tracing a route, making the flight easier and helping us to save batteries, as we will avoid erratic trajectories that always waste them.
• Parrot Anafi USA: A state-of-the-art drone designed for professional and security applications. With a Quad Bayer sensor offering a dynamic range of 14EV in HDR10 mode. It has a 48MP camera with up to 6x zoom, a flight range of up to 32′. It is an ideal drone for surveillance, inspection and aerial mapping operations.

• DJI Mavic 2 Pro: We always come back to the great DJI Mavic 2 Pro. This high-end drone features the famous Hasselblad 20 MP camera, a 1″ CMOS sensor and 4K recording capability. It offers a flight range of 31′ and a video transmission range of 8 km. Intelligent flight and omni-directional obstacle detection. This makes it one of the best options for professional drone photography and videography.
• DJI Mavic Air 2s: It is a foldable and portable drone that features a 20 MP camera, 1″ CMOS sensor and capable of recording video in 5.4K. It has a flight range of 31′ and a transmission range of 12km. Intelligent flight modes and omni-directional obstacle detection. It is one of the best drones of 2023 for creative photo and video. Versatile and powerful as it0 is.
• Autel Evo II Pro: The Autel Evo II is a professional drone featuring a camera with a 1″ CMOS sensor and 6K resolution capable of recording video up to 9km, intelligent flight modes and omni-directional obstacle detection. It is a great choice for mapping and industrial applications.
• DJI Phantom 3 Standard: This is a more affordable budget drone with a 12 MP camera capable of recording Full HD video. It offers a flight range of up to 25′, and a transmission range of 500 metres.
• MAVIC 3M: The Mavic 3M is a drone that combines an RGB camera with 4 multispectral cameras. It has a 20 MP 4/3 CMOS RGB and RTK (satellite positioning) camera. This drone is suitable for precision agriculture, as you can see in the following video.

This has been my personal selection of the best and most affordable drones you can buy for photogrammetry.

Remember that by purchasing some of these products, for you at no extra cost from these links, you help to maintain my website, Javier Gómiz, and to continue offering you the best information about photography and video with drones.

Process and steps for photogrammetry with drones

This image capturing technique is very similar to the process of panoramic photography, and like panoramic photography, if you want to know how to get a good photogrammetry, I recommend you to follow the steps below:

Pre-flight photogrammetry

1. RAW images: We will need a type of drone that allows us to take RAW photographs with which to match the configuration and characteristics of all the photographs obtained.
2. Weather: Normally we will look for cloudy but bright days to avoid harsh shadows and to have a softer and more homogeneous lighting throughout our scene.
3. Image acquisition correlation: Try to take correlative images to make it easier for the software to assemble 3D images during rendering.
4. Manual flights: If they are not very specific professional flights, personally, I recommend flying and taking pictures manually and without using waypoints. We will be able to focus on the areas we are most interested in. If you need to make more precise photogrammetries with drones and more accurate measurements, I recommend the drones with more specific systems that I have already mentioned.
5. Nooks and crannies: Check and make sure that the pictures you take reach those “hidden” corners and angles, by tilting and balancing the gimbal of the drone until you reach them well, you will avoid “patching without information” in your final project.
6. Configuración de la cámara correcta:
   • White balance between 5200-5700 (for this kind of cloudy day)
   • Highest quality resolution of photographs
   • Use the 4:3 format (horizontal photos) and avoid wide-angle shots that tend to distort the edges and especially the corners.
   • Ensure that each photograph is in focus before shooting.

Post-flight photogrammetry

1. Image processing: The images we have captured are downloaded and processed with special software for photogrammetry, which I will talk about in the next point.
2. 3D model generation: Using this information obtained from the image matching, a 3D model of the area or object of interest is generated. This model is an accurate and detailed three-dimensional representation of the terrain, building or object we have captured.
3. Analysis and application: Once the 3D model has been generated, it can be used for different analyses and applications as described below.

Best free software for photogrammetry with drones

Here are the best free programmes for 3D photogrammetry with drones:

• Meshroom
• Regard3D
• Colmap
• OpenMVS
• VisualSFM

There are also paid software and programmes for photogrammetry with drones, which offer more advanced features that may be of interest to us when developing our photogrammetry project with drones:

• Agisoft Metashape
• Pix4Dmapper
• RealityCapture
• PhotoScan de Agisoft
• 3DF Zephyr de 3Dflow
• ContextCapture de Bentley Systems

Once you have obtained your 3D photogrammetry with any of these programmes, you can use programmes such as 3D MAX or AUTOCAD to finish it.

If the purpose of your project is to isolate a certain object and you want to apply an environment or scenery to it, you can use other programs such as Lumion or Blender.

Finally, to obtain our playback file, I advise you to import all the material obtained so far into video editing programmes such as Premiere or Da Vinci.

Applications of photogrammetry with drones

I will tell you which are the most common in everyday life:

Cartography and topography

3D photography allows the creation of high-precision and high-resolution topographic maps and orthophotos. These maps are used for urban planning, natural resource management, natural disaster risk assessment, infrastructure management, among other applications.

By taking a professional drone pilot course in photogrammetry and topography, you will gain the knowledge and skills to plan, carry out and produce photogrammetric and topographic data of the scenarios you want.

Precision farming

Drones equipped with multispectral cameras can capture images of crop fields at different wavelengths, enabling real-time analysis and monitoring of plant health. This helps in early disease detection, optimisation of irrigation and fertiliser application, and in decision making to improve agricultural productivity.

By taking a professional drone pilot course in precision agriculture you will acquire knowledge and skills in the early detection of the condition of different types of crops using drones.

Infrastructure inspection

3D drone photogrammetry can be used for the inspection of bridges, roads, railways, power towers, buildings and other structures. Drones can safely access hard-to-reach areas and capture images that enable defect detection, structural condition assessment and maintenance planning.

In the Professional Course in Technical Inspections + Pix4D Certification you will acquire the knowledge and skills necessary to operate unmanned aircraft. You will learn how to analyse wind farms, power lines, solar panels and telecommunication towers.

Architecture and construction

3D models generated from 3D drone photogrammetry can be used in design planning, project visualisation, construction feasibility assessment and monitoring the progress of a construction site.

Tourism and cultural heritage

3D drone photogrammetry can be used for the documentation and preservation of archaeological sites, monuments, cultural heritage and tourist attractions.

Environment and conservation

Drones equipped with high-resolution sensors can capture images of protected natural areas, wildlife habitats and fragile ecosystems. This allows monitoring of the environment, identification of changes in vegetation, detection of endangered species and planning of conservation actions.

Advantages of aerial photogrammetry over traditional photogrammetry

The advantages are clear, and to my mind quite obvious, such as:

• Speed and efficiency in data capture
• Ease of access to hard-to-reach areas.
• Image capture security. You will avoid physically exposing yourself to situations in which taking a photo could be dangerous.

All this makes drone photogrammetry an interesting, valuable and fundamental tool in many sectors.

Expert in photogrammetry with drones

Severino Martínez is one of the leading experts and benchmarks in drone photogrammetry in Spain. He has some very interesting work that may enlighten you in this emerging world of drone photogrammetry.

I invite you to see the work of Severino Martínez in the interview that Rafa Ocón did with him in Droneguru.

What do you think about photogrammetry with drones? Did you know this technique? I read you!