Hi,
I've been trying to figure out what's the best way to accurately plan my flights for photogrammetry use. I'm having a bit of a difficult time calculating the necessary distances between photos at different altitudes, for achieving 70% / 40% overlap.
I have found a few simple formulas for doing this, but they all use the "format size" as data input; and basically, I don't know what it goes here for a Canon sx260 hs. I know the sensor size (6.2mm x 4.6mm), but I guess this is not what I'm supposed to use in the formula, as this would result in taking photos every couple meters, even flying at 100m or 200m.
Any help would be appreciated.
M
Replies
I've been using APM2.5 and the Phantom FX-61 frame to map forests for 2 years now. See my latest posts about photometry based point clouds.
Color Coded Height Ramping For Measuring Entire Forests.
http://www.ents-bbs.org/viewtopic.php?f=235&t=6491
Enchanted Forest Surveyed For the First Time Ever
http://www.ents-bbs.org/viewtopic.php?f=69&t=6490
Structure From Motion To Produce High Resolution Point Clouds
http://www.ents-bbs.org/viewtopic.php?f=235&t=5544
Aerial Surveying For Tall Trees Using UAVs
http://www.ents-bbs.org/viewtopic.php?f=235&t=5200
It is quite easy to generate very accurate point clouds using photo-bursts from a $200 camera. Just make sure you have a really fast camera. The most overlap the better. Don't worry about overlap percentage...just take 1GB of photo-bursting over the target with lens pointed normal to ground. The structure from motion algorithm by UAW will produce a better point cloud with random overlaps and the more the better. Just make sure prior and fore image have overlap. keep sequences registered for entire photo-burst otherwise you'll get disjointed point clouds(which can me merged with software). If camera is point not 90 degrees to ground your point cloud will be significantly les dense. I use the mission planner trigger output to a servo attached to a LUMIX10x CMOS camera FZ7-$200 on amazon. I can program the photo-burst precisely for awesome 3D point clouds of specific tree crowns or structures, or wide areas. The cost is pennies on the dollar compared to traditional LiDAR. The next hurdle is determining scale of the point cloud. Email me for more information if interested.
website www.landmarktrees.net
Thank you Max Messinger for describing Mission Planner’s Grid feature. Looks like everything is there.
Hello Forest Mapper and I am so glad to find someone with that much experience in using UAV for photogrammetry purpose.
I would very much appreciate if you can share your expertise to help me choose the affordable UAV, camera and other necessary add-ons to perform an accurate photogrammetry survey.
I expect to:
1) Keep a low budget
2) Use copter not plane
3) Use free software to plan a mission and pre-configure autonomous flight
4) Use <$200 range camera
5) Insert copter’s GPS coordinates as GPS tag of the pictures, not the camera’s
6) Achieve at least 15 minutes flight time
7) Configure a copter to “return home” in case of low battery alert
Steaming live video could be a case in the future, but it is not required now, as long as I am able to see copter’s current location on my pc.
I visited http://www.landmarktrees.net/ but found two e-mails. Not sure which one is yours.
Looking forward to hearing from you and thank you in advance.
http://www.suasnews.com/2011/11/10219/the-secrets-of-photomapping-a...
I use Canon S100 for photomapping. At 24mm equivelant focal length, the photo width is 1.28 times of the altitude, i.e., photo width is 256m at when altitude is 200m.
Hi Manuel,
you can use a spreadsheet for flight planning:
http://www.dronesimaging.com/en/solutions/documentation/
Good luck
Hello!
I`m Trying to produce some terrain mapping. I use an SX260HS with the CHDK interval script, and choose with 3sec interval on my 550 Hexacopter. Tried on auto and Tv modes, but all the photos are blurred. Can you help me about the settings you use on the camera? Supose you use in manual mode...
When i solve this problem, i`ll try to use script and cable to connect the camera shutter to the Arducopter!
Thank`s in advance,
Miguel
Hey Miguel,
Unfortunately, the SX260 doesn't work well at all with multicopters due to vibration affecting the optical lens stabilization. Try an S100 or a plane.
( Here is an side-by-side comparation of the 3 models:
http://www.dpreview.com/products/compare/side-by-side?products=cano... )
I have the S200 OEM. It is awesome.. I think Laser Tech has it outsourced by a Chinese company. This is the best laser sensor for UAV, bar none. I use it for collision avoidance and height verification.
Here's a list of compatible cameras. It looks like both of those will work with CHDK.
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