In-wing camera for aerial photography

[Greg Arehart]

To answer a few questions:

First - how difficult would it be to install similar setup in already closed wing?

It would be a pain but not impossible. You would have to work through the window hole to install everything. However, if properly planned it might not be too difficult to do. If you look at Figure 1, note that the cross-ribs are actually screwed to the angle brackets and thus are removable. The only permanent part of the installation is the brackets riveted to the original wings. So one could build the entire installation outside and with some careful and creative riveting (pulled rivets should work), place the brackets appropriately and then install the remainder of the parts (kind of like building a ship in a bottle...).

Second - how much may it cost to machine two metal backing plates?

I would guess that this might cost you $100 plus the cost of the Al plate. It is a relatively simple machining task and wouldn't take more than a half hour at a good shop. Alternatively, you could just cut several 1/8-inch thick pieces and make a sandwich rather than using a single machined piece. That would save the cost of a machine shop and serve the same purpose.

How difficult would it be to replace the camera should it fail or you decide to upgrade as technology gets more sophisticated?

Very simple. The camera is held in by the Z brackets plus the normal tripod knurled knob on the bottom of the camera (not easily seen in the photos). Any camera of similar size could be substituted into the system by modifying the brackets. One would, of course, have to redo the power wiring and on-off switch wiring. Almost all cameras these days come with the USB connection built in already, so that is simply a plug-in item. Worst case is if the technology gets larger, one could rebuild the entire apparatus since there is more room in the bay (Figure 6). Unlikely technology is going to get larger, but one never knows...

You could always blow a bubble cover, that would allow a longer camera to sit in your wing.

True, and I thought of that but wanted to keep it simple and inexpensive. The window is easily replaced by going to the local plastics shop. A bubble window would allow for more tilt angle, but I can also tilt the entire airplane! The camera I am using already has 6x optical zoom, so a longer lens doesn't seem necessary to me at this point. Note that I have done a minimal amount of testing of the camera with the lens zoomed, so don't know what the vibration issues might be.

Why did you mount it into the structure of the wing rather than in an external pod of some sort?

Less drag, simpler (in my mind anyway), and better looking. Mostly personal preference. Might also be better from a vibration standpoint. I could see the advantages of an external pod with a simple plug-in and a couple bolts on a bracket.

And for that matter why did you locate it in the wing and not the fuselage?

Has to be on the wing. I don't know about your belly, but mine has some oil constantly there (still working on that aspect of things!) which would potentially cause distortion in the window (like raindrops). Hot exhaust gases would also cause optical distortion under the fuselage. One could mount the camera in the front corners of the fuselage, but there's alreacy enough junk there with the fuel line vents, rudder pedals, etc. And my thinking was that there was likely to be more vibration in the fuselage than in the wing.

Did you consider using a gimballed mirror with a fixed camera?

Interesting idea, and no I did not consider this. I suspect again there is potential for vibration issues (moreso than with the camera only), plus the camera would take a mirror image requiring more image processing (not to mention the confusion of looking at the viewfinder backwards!).

Does the software you use tag the photos with GPS lat/lon or stitch mosaics?

The Breeze software does not do any tagging, but it is a simple matter to carry a GPS unit and, provided the GPS and camera clocks are synchronized, you can geotag the photos later at home. If you would like, send me a pm with your email address and I will send you a KMZ file that you can open in google earth and see both our flight path and the linked photos (these are from a handheld in the cockpit, but the idea is the same). I am thinking of buying a new laptop that has an embedded GPS unit (a lot of them do now, kind of like the iPhone) that would make this geotagging almost instantaneous. I don't have the software to stitch images, but have colleagues that can do this. There are some potential issues with image distortion at the edges, probably a bit more so than the normal BLM aerial photos, but the new software can apparently deal with that reasonably effectively. It's really out of my area of expertise, but I am aware that it exists.

Another note. This camera has image stabilization built in, so that probably helps with vibration issues. Most modern cameras that have significant zoom capabilities have this feature.

greg

[6S4 Hugo]

Originally Posted by Greg Arehart

I don't have the software to stitch images, but have colleagues that can do this. There are some potential issues with image distortion at the edges, probably a bit more so than the normal BLM aerial photos, but the new software can apparently deal with that reasonably effectively. It's really out of my area of expertise, but I am aware that it exists.

Another note. This camera has image stabilization built in, so that probably helps with vibration issues. Most modern cameras that have significant zoom capabilities have this feature.

greg

Microsoft ICE is a free and easy to use program that will stitch photos together. It is the fastest and easiest programs that I have ever used. The price made it a sure winner for me.

[GaryStofer]

This installation looks excellent!

A few years ago I put a camera in the outboard wing access panel of my RV8 and made a wireless remote control for the camera. It worked reasonably well, but since I had the cam mounted hard to the craft it was rather difficult to take precise pictures, especially in unsteady air and down low (below 5000ft).

I eventually made a camera stabilization device based on solid state gyros, accelerometers and software to hold the camera steady in pitch and roll then successfully flew it on board of a RC helicopter.

Because I used a rather large camera at the time I was not able to get the cam and gimbal mechanism back into the wing access plate hole and subsequently lost focus on the project.... With the small cameras available now this would not be a problem however.

If there is interest for such a thing on this forum I'd be inclined to pick up where I left off and put together a cam stabilization kit for the RVs.

Gary Stofer , N427GS, RV8,

[Greg Arehart]

Gary,

A lot of the digital cameras now have built-in image stabilization. Most of my photos have been taken at 1/1000 second (depth of field is not an issue) and I seem to get pretty clear sharp shots. It would be interesting to see whether your stabilization setup would make a difference. Certainly it would allow for taking photos at lower light settings that require a longer shutter speed. An additional benefit (sounds like from your description) would be that one could set up the camera at a specific angle (say, vertically) and the gyros would take out some/all of the tilt associated with banks and changing angle of attack. I would be interested in knowing what it would take to do this. If you would rather discuss off-list, feel free to email (arehartatunrdotedu) or pm me.

greg

[loopfuzz]

That looks really cool. Nice work!

[GaryStofer]

The stabilization with external means (i.e. Servos) is not for image stabilization due to vibration but for motion stabilization of the platform. It is a means to keep the camera pointing at the same spot even though the aircraft pitches and rolls, within reasonable limits of course.

When I flew my fixed mounted camera I had a heck of a time flying excatly "over" the target. When I needed to make a slight correction to my course I would lift my wing and the cam would point out or in and I would loose the target altogether..... Then I ended up flying unnecessarily high so I would have a bigger field of view, but of course that ate into the final resolution of the picture.

The electronic I made allowed for manual control of the cameras two axis, so that I could tilt and pan the camera with two knobs on the remote control. Then the electronic holds that angle even though the platform rolls and pitches about. I was thinking of adding a feature where the camera automatically pans front to back as you fly directly over an object by tying into the airspeed and knowing AGL , so that you get a series of shots at different angles, but I never got to that point.

Gary

[trib]

How do you aim your camera? Do you just have it zoomed so the area is so large you get the target- but lose quality? Is there a remote monitor that is used to see what the camera sees? I'm very interested in mounting a camera and am curious on the common practice when using these in an RV.

[GaryStofer]

The Canon Cameras (A530 for ex) have a video out that is active when shooting. You need a small video monitor in the cockpit to see what the camera sees. Also most of the Canon cams can run a different firmware (search for CHDK and camera). This allows you to make a remote trigger which connects to the USB plug of the camera, eliminating my RC-servo remote control for the trigger.

I have started to make a gimbal mount for the Canon camera, so that the cam can be remotely positioned from the cockpit and then be held steady by gyros ( in the roll axis at least), however I did not get any interest for this from the forum and so I didn't continue past the proof of concept. If people would be interested in this I would consider putting together a kit...

Gary

[Scott_F]

Originally Posted by GaryStofer

If people would be interested in this I would consider putting together a kit...

Gary

Gary,
How hard (and expensive) would this be to do? I've always been interested in remote sensing type aerial photography, so I would be iterested in doing it. But I'm still a long way from flying...

[Greg Arehart]

Tim,

Aim using the servos if necessary. The image is relayed to my laptop in the passenger seat and the operator just pushes the "take picture" button and captures the image that s/he is looking at on the computer screen. As I write this I am sitting here awaiting the Panasonic guy who is delivering a test laptop that is 1000 nits bright and (hopefully) will make seeing the picture in the cockpit of an RV easier to do. So far, we've had to have the operator mostly under a piece of cardboard or cloth to cut the light and be able to see the laptop screen.

greg