Hello forum,
First of all some background...
Having spent a good 2 years playing about with an Skywalker, Ursus and a Canon camera running CHDK, and designing my own uav, which actually flew recently ,I have come to the conclusion that flying wings may just be the best type of platform for short range aerial mapping tasks to create DEM, DSM models for GIS purposes.
The Skywalker was okay (but quite fragile, and now in pieces!), but I think it is too small to fit a roll gimbal on it. And I've found that if pictures are taken on a slight angle, it is very difficult to use software to tile them up nicely. this is my best effort, but far from perfect. The roads on the right do not line up as the camera must have been on a 45 degree angle when the picture was taken. (click for larger resolution) - It was taken using an ixus80 attached to an URSUS Airframe
Realizing that I need to use an airframe that can accommodate a stabilized roll gimbal, i started to design and build my own twin boom design. It took 6 months from initial design, to first test flight. It has a wingspan of 2.4m - AUW of 5kg, and a flight duration of around 30 minutes with 2 x 5000mah packs. However it needs a heck of a lot of room to take off and land, something i don't have in the areas i need to take photos.
Picture of twin boom plane...
What are peoples experiences with using flying wings for this reason? I have the following types of flying wings, and wondering which one is the best to begin with?
- jp-si 48" span Zagi
- Scaled up 60" span jp-si Zagi (hot wire cut by myself)
- x8 2m wing
I have been using the 60" wing to test the APM2 and 3dr radios. And was using the URSUS (now in pieces after a nasty crash!) as a test platform to practice with the Canon CHDK Kit.
Here's a few pictures of the wing and camera....(click images for larger version.)
My question is how straight forward do you think it is to fit a roll stabilized gimbal to any of the above airframes?
Replies
Small update - In order to measure progress on my aerial photo taking abilities, I thought i'd compare a dataset of a flight i did last year with a dataset i took yesterday using what i have learnt in the passed several months. Initially when creating this blog, I flew over a local cliff and beach area, It was using an Ursus airframe and IXUS80 camera, the flight was entirely manual, and I did not capture large areas.
I have just flown over the same area again, This time using a an x5, sx230, and APM 2.5 flightpath. I flew 2 flights, and collected about 400 hi-res geo-referenced photographs. I have run these through ICE, and the output isn't great (as i had to downsize the images from 4000x3000 to 2000x750), but thought i'd share the results...
I plan on doing a bit more with this dataset, including running it through visual SFM, CMVS, and hopefully CMPMVS. I have learnt that when reducing the quality of photos for processing, lots of match points are removed, and the software struggles significantly. This map is much bigger than the original, but far from perfect! Interesting landscape though....
Nice photo, I have an Aurora too, great radio :)
Small build update - I'ts been a quiet few weeks what with moving house and all.....! but i've been doing a bit of tinkering, and have now modified the x5 to carry the larger Canon SX230. Hopefully this will give better quality pictures. It has a wider lens, and the CHDK is better with this camera. I should also be able to use shorter shutter speeds in cloudy conditions. The Ixus 120 struggles in cloudy conditions. we'll see. I also cut the hatch into 3, as the closing mechanis isn't great on the x5, and its been lightened by 100g by removing un necessary foam and fixings.
Hopefully doing the first flight in a few days...some pics
On a completely different note, I re-assembled my 2.5m twin boom aircraft with the intension of flying it this week... I'm gonna stick and APM on it and see how it does... I'm going to hopefully get some performance figures as well. I know it isnt that great in terms of flight time...Here she is! a bit rough around the edges, but i intend on making another one of these for larger mapping missions, and will use all the lessons learnt from this one... that's my winter project sorted!
I've only now got round to downloading the flight logs form the plane for the flight over the river mouth....What a colourful mess! This was 4 flights. One of the flights was repeated due to the fact the camera was not taking pictures, towards the left hand side of the image.
Now, how about a data set of this place.....
A number of things need to happen before I can do this, but i reckon the trust that owns the island would allow it....and probably like the data...
Rich,
So far so good. I ran the SIFT and complete 3D reconstruction and it resulted in a single promising looking model.
Here is the Sparse 3D point cloud:
FYI, I almost completed the second FLight Riot post processing tutorial last night. I just want to make some edits so it flows better but it shows very simply how to run the outputs of VisualSFM (.cmp) through CMPMVS and then sisplay the 3D model in Meshlab.
B
Rich,
I couldn't reply under your last message either.
A couple thoughts...
I think that VisualSFM, unlike many other post processing software, actually benefits from a variety of heights and angles. These shots may not be great for the aerial imagery and resulting stitch but they seem to be very beneficial to the point cloud creation. This can certainly be further tested.
I can't wait to see a more thorough set of pics of Southerndown. It would be PERFECT for a CMPMVS tutorial. I mean it really doesn't get much better in terms of showing what the post processing is capable of creating. Unfortunately, during the summer I have to stay far from beaches as well.
As for the river mouth data set (i think you know what I'm about to say here) feel free to zip it up and ship it over to me.
Let's see what kind of ortho and model we can squeeze out of it!
The testing goes much quicker with more than one person creating data to process :)
B
Here is Autopano GIGAs attempt at stitching the images...
a bit better than ICE, but far from perfect....
Here is Microsoft ICE's attempt at stitching the photos from monday's flight...
I'd like to be able to create a textured 3d model, using the orthophoto, and the point cloud....
Great work Richard, I'm behind you with similar proyect, I'm in Skywalker step ;) with some difficulties to lauch it, so when I saw the catapult I think a flying wing perhaps its a good idea and discover your post :)
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