Drone Mission For 3D Imaging

Screen capture from DroneDeploy app

A while back, I did a video series on the tool-chain required to get 3D drone acquired imagery processed into HTML format so anyone can view it.  I have had some requests to give more details on the drone mapping mission phase.  Of all the steps in the process, flying the drone mission is probably the easiest.  And if you do not want to specialize in all the other technology, flying your own mission will give you the image sets to send out for processing.

When you fly an automated mapping mission, you will be using a different app to pilot your drone.  The DJI Go app is probably what you are used to using but a mapping app can fly your drone as well.  There are a number of free apps that will work but I use an app called Drone Deploy.  They have a paid processing service but the app is free.  You can create a free account with Drone Deploy and plan your flight on a PC or right in the app.

In the planning phase, you will draw out the area you wish to map, choose an altitude and overlap.  the images need to overlap by 60-90% (front lap and side lap) depending on what you are imaging.  Detailed features like trees are more challenging and need more overlap from a higher altitude.  A flat field could be mapped at 200 feet with 60% overlap with great results.  Once you are ready, you hit the ‘Fly’ button and your drone will take off, fly the grid and land near the take-off point.  You will then have a batch of images stored in the drone’s SD card.  At this point I look at the images and remove any that may not be needed.  It will speed up processing if duplicate or oblique images are removed.  When your drone makes its turns, sometimes it takes photos while turning that are rotated but redundant.  so I usually remove two or three images from each turn and any images at the beginning or end that do not fit the grid.

Scanned with a Phantom 4, Exported 3D model with Blend4Web

If you want to do more specialized imaging, like 3D scanning a structure, you will need to add in some oblique photo angles.  Basically, run your drone around the object in ascending circles to get side images.

Now that you have your batch of images, they are ready to be processed into a 3D model (or georeferenced image).  There are some free trial services you can try.  Pix4D and DroneDeploy both have free trial options.  OpenDroneMap is open source and free, though a bit more technical to get it up and running.  3DXMedia can go a step further and process your imagery into a web ready HTML format.  If you are interested having this done or learning how to do it yourself, feel free to contact us.

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