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Saturday, June 8, 2013

24. More RasPi Cam Pictures

I thought I would try hitching up my Raspberry Pi camera to my scope.  The scope is an Opticron Mighty Midget Waterproof Field Scope which has a 14 to 36 times zoom with a 50 mm objective.  There is a UV filter on the objective and the outside diameter of the eyepiece end is about 40 mm.   

The angle of the Pi with its WiFi adapter attached, is not ideal for picking up the WiFi network so that there are only certain positions in the upstairs room where I can pick up WiFi and at the same time get a view through the windows.  The position shown below happens to be almost directly above the WiFi router downstairs, with only a ceiling and wooden floor (no bricks, concrete or steel) in between.

Here's the setup:


The Mighty Midget was mounted on a tripod, with the RasPi Cam fitted to the lens cover, with the Pi hanging on for dear life below.  

It's very difficult to get reasonable results by just sticking the RasPi Cam on the end with tape, which I discovered with my time lapse sequences.  The camera gradually moves if there is any tension on the tape, especially if the room is very warm, or there's very strong sunshine about so I cannibalised my plastic eyepiece lens cover by boring a 7.5mm x 7.5mm square hole in the centre for pushing the camera part of the camera board into.  Here are some still pictures, some of which I straightened and cropped a little using Photoshop Elements:
This first picture, shown raw, was taken on a hazy sunny morning.  The quality hasn't been enhanced, so the internal window reflections add to the haze.  The buildings in the background are about 4 miles away.

The following images have been taken at the lowest zoom setting, and have been enhanced using Photoshop Elements.  

The boat above is about a half mile away.

These buildings are up to 4 miles away.

Distance here is up to about 4 miles.

The background buildings above are about 2 miles away.


The same buildings above imaged with maximum zoom.  Sharpness falls off with high zoom on this scope.

Distance here is about 3 miles.  The image was taken at minimum zoom.

Not bad for casual shots through the window?  Make sure you click on these to see them full size!

Here is a time lapse series taken with the field scope.  It's a 60-image series taken at 1 second intervals:



For the next one, I managed to get a setup with the Pi Cam properly aligned and with improved WiFi reception.  You can see a Jet Ski pulling a Banana Boat going past.  There was a little jitter on the video despite my binning of sticky tape - there's probably something elasticy - maybe the rubber lens cover that I cannibalised.  

I was able to fix this using Kang Li & Stephen Kang's Image Stabiliser Plugin for ImageJ, and it works a treat!  See http://www.cs.cmu.edu/~kangli/code/Image_Stabilizer.html  

I would certainly recommend ImageJ for image processing - see http://imagej.nih.gov/ij/features.html - it's Java based, open source, regularly updated, and there's a world of Plugins available, and - if you know a little Java, you can write your own Plugins!!.

Have a look at these YouTube videos full screen:

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