Getting a camera into the air using a UAV is not too much of a problem. Provided that the UAV can take the weight of the camera and is sufficiently balanced, getting an aerial image is quite a simple operation. The difficulty is when the ambient light is not enough to enable the camera to shoot with enough shutter speed to overcome the movement and vibrations of the UAV.

Having a good pitch and roll gyro stabilised camera mount with vibration damping is essential. The camera is then always facing at the correct angle to the ground and will not be affected by the roll of the UAV so the camera always stays level. However should the light levels be so low that the camera needs a slow shutter speed then the images will suffer from camera shake.

If you use a camera without stabilisation then a shutter speed of 1/500th sec is about a slow as you can get away with. A good image stabilised camera can manage 1/125th sec perhaps 1/100thsec. Elelctronic image stabilsation such as 'pixel tracking' can produce excellent results. This is where the camera detects movement in the image and maps the image over itself thereby creating a crisp image.

The image below was taken on a very dull December morning in Scotland. The aperature was f3.5 and the shutter speed 1/25th sec. Although we could have increased the ISO to 400 or even 800 to increase the shutter speed that would have compromised the image quality. Even with the ISO at 160 and the shutter speed very low the pixel tracking creates a very clear image under very difficult lighting and operational conditions. This image is untouched and is not post processed.

Our UAV is set to take photos every 3 secs with a Pentax W90 12MP camera. That means we can take many photos in one location and by rotating the UAV slightly we can get a photographic 'sweep' of the area. It is important to keep the UAV as still as possible during the sweep and it is useful to keep the 'Altitude Hold' and GPS on at the same time. Alternatively with the new firmware 0.86 it is possible to set the camera to trigger using a 'Waypoint Event' and rotate the UAV a fixed number of degrees between shots.

Using Microsoft ICE (Image Composite Editor) - available here we can simply choose the best photos to stitch together to make a large composite image. See some examples here

We have tested the new firmware and after a few modifications the Flight Control 0.86c and Navigational Control 0.26e has proved to be acceptable and we will be using these upgrades for our flights.

The new firmware allows us to log the flight running temperatures and current of the speed controllers at approx 1 sec intervals. Any possible faults with the motors can be seen by analysing the data. Also the new Waypoint software allows us to simply program the Navigational Control board with an grid array of waypoints or a radial array of a panoramic array. This will simplify on site waypoint generation and allow us to quickly set up new waypoint flights.