A Good Field Day: Eight Full Flights!

June 2nd, 2013 was a good field day for photo collection! I flew eight flights with Crimson, the Arducopter hexa with Mikrokopter motors and frame. Five flights were for the "matrix", this summer's big project of comparing the effect of different flight conditions on 3D scan quality. This condition was diffuse lighting, high wind, flying 40m above the canopy, with 50% side overlap. The last three flights were to test our georeferencing method. Jonathan and Dana set out orange buckets over known GPS coordinated, which we will check for error in the georeferenced point cloud built from this day's photos.

The white flags on the ground represent the eight spots the copter landed on in auto landing mode. All eight flights were fully autonomous, all I had to do was rev up the props and enable auto mode, then disable auto mode to cut the motors once it touched back down. The GPS in the copter seems pretty reliable for auto landing, seeing as the copter always landed within the same 2m circle. The white flags coming out of my hat are "antennas" which actually help me gauge the wind speed, because the flags flap more in stronger wind, which I can feel with my head.

This is the ground control station. Aside from the orange bucket and Dana's lunch on the left, everything except the copter, tarp, and umbrella gets packed up into the backpack for easy transport.

This is representative of the eight flights. As you can see, the path sometimes curves. I suspect it is due to the high wind gusts we were flying in. These kind of curves were not present on calm days, so they will hopefully manifest themselves as a measurable difference in scan quality. That is the point of flying the "matrix" of different conditions. This flight is the standard 250x250 meter collection

A typical photo from repetition 1. All photos were very detailed, I'm not seeing any intermittent blurring like I used to with the SD4000 cameras of old. The color is a bit dark, but it looks like this in full sun as well, since the color is always calibrated off of our grey camera card. In the future, we may try using a darker card to obtain brighter pictures. Note the orange bucket on the lower edge of the photo.

Cross posted from the Ecosynth.org blog.

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Comment by Randy on July 3, 2013 at 11:18am

Nicely done.  You may find that setting the WP_YAW_BEHAVIOR parameter to 0 which will disable the copter from turning as it flies removes some of the curves that you can see at the beginning of the legs.

Comment by wbal57 on July 3, 2013 at 11:22am

What camera were you using for this mission?

Comment by Stephen Zidek on July 3, 2013 at 11:26am

Thanks Randy, but I'm already using condition yaw before every point to keep it pointed at 38 degrees (the heading the tracks follow).  I'll change WP_YAW_BEHAVIOR though, then I should only need one condition yaw at the beginning of the file!

Here's a KMZ from a calmer day.  Still a few curves, but for the most part much better.  I suspect that I may need to work on the compass, but since these flights are part of a "matrix" of varying flight conditions, I'm not changing anything right now.

Comment by Stephen Zidek on July 3, 2013 at 11:28am

I did just notice that my picture is perpendicular to the road, yet the KML shows the copter flying over that road at an angle.  Strange that I could be off by what looks like 10 degrees and still get nice looking tracks.  I'm sure the camera is mounted straight.

Comment by Randy on July 3, 2013 at 11:48am

The navigation controller can certainly handle 10degrees of error and still get the copter to it's destination pretty well, you'll just get more and more curved paths and/or "toilet bowling".  Of course I don't see any toilet bowling in your tracks .. to be honest, i'm not sure how bad the error needs to be for it to start showing up but I know that anything less than 45 degrees of error and it will reach the target eventually.

Comment by Stephen Zidek on July 3, 2013 at 3:10pm

@wbal57 I use the Canon ELPH 520 in a "waterproof" (not anymore since I drilled holes in it) case to protect the lens, with velcro holding the shutter button down for continuous shooting.  Mounting is straight down with rubber shock mounts.


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