Introduction To UAV Photogrammetry And Lidar Mapping Basics

The increasing use of UAVs for photogrammetry and lidar mapping in aerial surveys is not surprising.  Using GPS enabled UAVs for aerial surveying is very cost effective in comparison to hiring an aircraft with photogrammetry equipment.  Because UAVs are relatively inexpensive, many organisations will have their own fleet, allowing for rapid surveys over large land areas where required. 

With GPS-equipped drones, digital cameras and powerful computers, surveys with an accuracy down to 1 to 2 cm is very possible.

In this post we take an overall look at this technology and which sectors are benefiting by using UAVs for Photogrammetry and lidar mapping.

The use of quadcopters and multirotors in photogrammetry and lidar mapping is still in the very early stages.  There are so many terrific uses for drones and the opportunities are vast and exciting. Now is the best time to learn about UAVs, photogrammetry, 3D and lidar mapping.

If you are interested in pursuing a UAV Photogrammetry business or similar, buy the best quadcopter and sensors you can.  There is no point in having equipment that is not able to do the job or does it poorly.  There will be excellent work and opportunities in the many years to come in this industry and especially for owners of quality UAVs and equipment.

What Exactly Is UAV Photogrammetry

Photogrammetry is the science of making measurements from photographs. The output of photogrammetry is typically a map, a drawing or a 3D model of some real-world object or land mass.

3D Maps And Models 

To create 3d maps from aerial photogrammetry, the camera is mounted on the drone and is usually pointed vertically towards the ground. Using photogrammetry to create 3D models of monuments or statues, the camera is mounted horizontally on the UAV.

Multiple overlapping photos (80 to 90% overlap) of the ground or model are taken as the UAV flies along an autonomous programmed flight path called a waypoint.  To overlap photos of an object or land by 80 to 90% would be impossible to complete accurately by pilot navigation.  It is essential to have a UAV which has waypoint Navigation technology.

UAV LiDar Mapping Explained

UAV Lidar (Light Detection And Ranging) involves mounting a laser scanner on a UAV to measure the height of points in the landscape below the UAV.

UAVs with lidar scanners can capture hundreds of square kilometres in a single day. By measuring 10-80 points per square meter, a very detailed digital model of a landscape can be created.

The accuracy of the measurements allows the 3D models created to be used in any planning, design, and decision making processes across many sectors.

Lidar sensors can also pierce dense canopy and vegetation, making it possible to capture bare earth structure that satellites cannot see, as well as ground cover in enough detail to allow vegetation categorisation and change monitoring.

Photogrammetry And Lidar Uses 

Through the use UAV photogrammetry and lidar mapping, there are many products which can be extracted from the aerial imagery.  These products include:

• DEM / DTM / DSM (surface models)

• Orthophoto’s (geospatially corrected aerial images)

• 3D Building Models

• Contour Maps

• Planemetric features such as road edges and heights, signs, building footprints, etc.

• 3D vegetation modelling

• Volumetric Surveys

Here are some of the best uses of lidar and photogrammetry.  All of these sectors benefit for having precision 3D images of their projects.  They also benefit with increased efficiency and reduced costs than using traditional aircraft.

• Forestry Management and Planning

• Flood Modelling

• Pollution Modelling

• Mapping and Cartography

• Urban Planning

• Coastline Management

• Transport Planning

• Oil and Gas Exploration

• Quarries and Minerals (Volumetrics and Exploration)

• Archaeology

• Cellular Network Planning

Cameras For Photogrammetry And 3D Mapping

There are several drones with cameras which are ready made for 3D Mapping.  In reality, any drone equipped with an intervalometer on the camera would be suitable.  An intervalometer  triggers the camera shutter.  A minimum photo capture would be 1 photo every every 2 seconds.  The below cameras all work well for Photogrammetry and Mapping.

• Canon Cameras – S110, SX260

• Sony Cameras – QX1,DSC-RX100 A7R, A7, A7S, NEX-6, NEX-5R, NEX-5T, A5100

• Panasonic Cameras – GH3

GoPro camera lenses aren not great for creating aerial maps.  To get some sort of decent results, you would have to be flying higher than 400 ft (approx 120m).

Photogrammetry Best Practice 

From the Art Of Photogrammetry – If the photos aren’t good, then it’s going to put a ceiling on the quality of your 3D model, no matter how good the software is.  The photos should be as clear as possible.  If you were to zoom in on your aerial photos, are the small features blurry. If so try to figure this the reason and your 3D images will improve immensely.

Eliminate everything standing in the way of maximum sharpness. This is where more megapixels actually matters.  Shooting in RAW definitely helps.

Lighting is always important in photography. Bright, even lighting will allow you to have a small aperture to reduce the image’s depth of field.  Shallow depth-of-field is actually a bad thing for photogrammetry, because blurred details confuse the software. Our goal is to have high-detail, sharp, and flat imagery. That requires closing up the aperture, which means you need more light. Good lighting will also allow you to lower the ISO which will reduce grain, and it will allow you to have a high shutter speed which reduces motion blur.

Give the software only high resolution information. If you are mapping a sculpture or building and don’t need the background, then mask it out.

If one image is off or not aligning correctly with the images before and after it, then delete this image.  In many ways, you’re smarter than the software which will be stitching the images together.  Filtering out bad or off line photos before the software gets to work, will make the 3D Photogrammetry software as smooth as possible.

If its not in the picture, then It’s not in your mesh and 3D image.  Make sure you have the coverage you need to get all the details you want, because it’s difficult to go back and re-shoot in the exact same conditions.

If you are new to the world of photography, here is a terrific article with on aerial photography tips.

UAVs For Photogrammetry And 3D Mapping

Most of the drones highlighted below, you can read deeper into their features in our drone reviews on this website. Also check out 6 very affordable drones with Autopilot and GPS.

3DR X8-M Drone For Aerial Mapping

The 3DR X8-M comes as a full package which includes the quadcopter, the Canon high resolution 12 MP digital camera and also the Pix4DMapper 3rd edition software required for rendering the photos into 3D maps.  The 3DR X8-M has GPS, autonomous waypoint navigation, repeatable flight paths and is perfect for precision aerial maps and surveys.

The X8-M is one of the easiest UAVs to plan and program autonomous missions and creating 3D photogrammetry maps.

3DR Aero-M Fixed Wing UAV

The Aero-M is an all-in-one solution for creating high-resolution visual-spectrum aerial maps. It’s the perfect platform for acquiring highly detailed data for large-scale operations such as farming, construction, conservation, as well as search and rescue and emergency response. the Aero-M has a lightweight and tough foam frame.

The Aero-M package includes a Canon S100 high-resolution 12 MP camera, the powerful Pix4Dmapper LT 3DR Edition software which is used to create highly accurate, georeferenced and orthorectified mosaics.

View the last video below to see how easy it is to plan an autonomous mission with the Aero-M and also to create a 3D maps of a large area.

Trimble UX5 UAV

The Trimble UX5 ensures optimal image quality along with maximum photogrammetric accuracy. The UX5 camera has a large imaging sensor which captures very sharp, color-rich images, even in dark or cloudy conditions. The 24 MP camera and its custom optics give the UX5 the ability to capture data down to 2.0 cm (0.79 in) resolution.

The design of the Trimble UX5 means it can fly in practically all weather conditions.

Aeryon Scout Map Edition Quadcopter

The Aeryon sUAS is designed for any application that requires survey-grade accuracy orthomosaics, DSMs and point clouds from aerial or oblique imagery – and seamless integration with GIS, CAD, and traditional photogrammetry software.  The Aeryon Map Edition includes the Aeryon SkyRanger sUAS, the integrated imaging payload for image capture and Pix4Dmapper software to enable field and office image processing, including integrated tools for 3D output visualization and editing.

DJI Matrice 100 Customizable UAV

The Matrice 100 platform has all of DJI’s easy-to-fly technology built in. It includes the flight controller, propulsion system, GPS, DJI Lightbridge, a dedicated remote controller, and a rechargeable battery. It has additional expansion bays allowing you to add components such as cameras, infrared sensors and LiDar scanners used to create complex 3D Maps. The Matrice 100 has enhanced GPS with allows for highly accurate photogrammetry.   The enhanced GPS also allows you to track the Matrice 100’s position in real time, while enabling faster satellite acquisition, more accurate position holding and flight planning.

SenseFly eBee Pro Mapping UAV

The eBee mapping UAV is a fixed wing, fully autonomous drone which captures high-resolution aerial photos that you can transform into accurate 2D orthomosaics and 3D models. The eBee can cover up to 12 square kilometers (4.6 square miles) in a single flight, and over smaller areas, flying at lower altitudes, it can acquire images with a GSD of down to 1.5 cm/pixel.

The eBee comes with two software packages: eMotion (flight planning and control) & Postflight Terra 3D (professional photogrammetry).

DJI Ground Station With Photogrammetry

With the DJI Ground Station, there is photogrammetry software which  can be used to produce professional and accurate mapping. The Phantom 2 Vision and Vision+ have the Ground Station built into the Vision App.  For the Phantom 2, the Ground Station with Photogrammetry tool can be purhased.  That has now changed.

Special Note: On December 12, 2015, Google will stop supporting Google Earth and DJI’s PC Ground Station software is based on the Google Earth API.   This means that DJI will also discontinue support for PC Ground Station.

2 of DJI’s products, the Ace One WP flight controller and 900M Datalink, both of which rely on the PC Ground Station software, will also cease to be functional. The 2.4GHz Bluetooth Datalink’s PC Ground Station functionality will also cease to be functional, however the iPad Ground Station functions will not be affected.

DJI Phantom 3 And Inspire 1 Photogrammetry 

Only recently (September 2015), the latest DJI Inspire 1 and Phantom 3 models now have waypoint navigation and are now ready for Photogrammetry.  The best software to use is the Pix4Dmapper Mesh DJI edition.  More information on the Pix4DMapper software below.

DJI Spreading Wings S1000 For Mapping

The DJI Spreading Wings brand can be customized to carry many different types of cameras and sensors including those mentioned above which are ideal for Photogrammetry and Mapping.  In choosing a camera, you need to have a matching gimbal to carry the camera.  DJI are world leaders when it comes to drones, gimbal and camera stabilization.

Pix4Dmapper Mesh – DJI Special Edition

The Pix4Dmapper Mesh software has a special edition for DJI drones.  The Mesh software automatically converts your images into 3D models.  You can also get a preview of the 3d model or map on your phone within one hour after landing.  Then using the desktop software, you can edit and optimize your 3D models.

There is so much more you can do with this Mesh software including measuring lines and surfaces, create fly through videos, and export the model in full 3D textured mesh and video format.  You can rent the Pix4Dmapper Mesh software annually which includes all free updates.

This Pix4Dmapper Mesh DJI Edition now works with the Inspire 1 and Phantom 3.

UAVs Photogrammetry And LiDar Mapping Videos

This videos shows the monumental task of creating the 3D Model of the Christ the Redeemer Statue in Rio de Janeiro.

This next video comes from Tim Lucas which demonstrates how UAV’s carrying photogrammetry payloads are being used.

Below is a nice tutorial video on LiDar technology.  This video shows traditional aircraft being used for LiDar mapping.  However, we are already seeing that UAVs are more practical and cost effective for LiDar mapping.

This final video shows you how easy it is to create a 3D photogrammetry map of an area using the 3DR Aero-M fixed wing aircraft. With the right UAV, equipment and software, creating 3D images is pretty easy.