Tuesday, 9 April 2019

What lens and camera settings are recomended for UAV (drone) aerial imagery capture?



I have been toying with the idea of purchasing/bowrrowing a UAV and attempting to capture my own aerial imagery. I have pretty good DSLR Canon gear and several lenses but I am wondering what lens, focal length and camera settings, including capture intervals, vehicle speed, etc. are recommended.



Answer



All of the specific answers I can come up with would have likely already occurred to you as a photographer. A low distortion lens with a shorter focal length (based on your prospective altitude). High shutter speed to minimize motion/vibration impacts. Interval and speed are something of a function of your flight plan and altitude - I don't know if there are specific numbers to follow vs it being a equation to be solved for each flight since you want to ensure sufficient for in- and cross-track overlap. Generally speaking, from a camera settings standpoint you can just think of it as another type of panoramic stitching scenario.


Your best bet might be talking to DroneMapper. They are software as a service that aims to process images collected by UAVs, and as such offer recommendations on equipment and procedures - very generally in their FAQ, more specific on their Guidelines page, and several very specific PDF guides and informational papers under Documentation (all under Support on the nav menu). From various areas of that site:



For best results: Shutter Speed >= 1/1000th, Auto ISO, White Balance setting fixed to 'Sunlight', 'Day' or 'Cloudy' depending on sky conditions. We've also seen great results with a fixed ISO setting.


...a good rule of thumb to use is the camera shutter speed should be set at no lower than the time to move one half of a pixel...


We recommend > 60% in-track overlap (75% is a good target #). So for this example let's say you fly at a nominal 13 m/sec. 75% overlap in-track means that you move 52 m relative to the ground (75% of 209 m = 157 m; 209-157 m = 52m) and take a photo. At 13m/sec you need to take a photo every 4 sec. Depending on expected wind conditions and the actual UAV ground speed you may want to adjust your photo interval faster to maintain adequate overlap.




Other links: Two commercial companies developing in this field are SkySight Aerial Imaging and Falcon UAV; they might be willing to talk with you about some of your questions. Two other websites that may have some good info are DIY Drones and a section of the Virtual Terrain Project on collecting your own imagery.


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