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Thursday, June 20, 2013

25. Still Fiddling around with RasPiCam Time-Lapse and Video

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The recent spell of good weather here has given me the opportunity to snap away with the RasPiCam.  I've been using it so much recently that I actually thought the Pi had died - communications stopped and the LEDs on the Pi were off, despite the fact that the power was on and the input capacitor was hot.  I dismantled the whole setup and I was about to parcel up the Pi for return for repair under warranty (assuming there is a 12-month warranty), when a final test (measuring voltages etc) showed that all was well.  

Interestingly, I received my Pi on the 25-Jun-12, just under a year ago.  It's going fine now but the poor thing must have over-heated in the summer heat.  Mind you, it has been powered up for virtually all of that year since I got it!  Hopefully it's going to be OK.

Anyway, taking advantage of the sunshine for decent images, I made some more YouTube productions:

Above is a time lapse sequence of images taken at 10 second intervals.

Above is part of an overnight time lapse sequence at 15 minute intervals. I removed 4 or 5 hours of complete darkness.

This is a 10 minute time lapse sequence of images taken at 1 minute apart. The above images have been processed to remove haziness. I did this using ImageJ's Image -> Adjust-> Brightness/Contrast facility. Some of the above images are arguably over-processed, losing information.

Here's a 60 minute time lapse series of 60 images taken from Rostrevor, showing the changing light over Slieve Gullion and Warrenpoint:

Above is an un-processed 30-second mp4 video, not time-lapse, taken as:
raspivid -o video1.h264 -w 1080 -h 1080 -t 30000

(There's not a great deal happening in that scene).  The video was produced by using the previously installed gpac's MP4Box to convert the .h264 to .mp4 on the Pi itself:
MP4Box -add video1.h264 video1.mp4 

and now transferring the resulting mp4 file to my PC using WinSCP (not by email as before!), also previously described.

I used VideoPad Video Editor (free download) to read the mp4 file (some processing can be done by VideoPad) and export it as a sequence of jpeg's (1094 images) which ImageJ is able to import.  ImageJ can then File -> Save As -> AVI.  The AVI is a suitable format for YouTube input.  When no intermediate processing is to be done (as above) YouTube can import the untreated mp4 file:
Above is a screenshot of VideoPad in action.

You can see how hazy the above video is due to light scattering in the 2 mile distance in humid conditions.  The heat haze also adds to the unsharpness of the images due to convection currents.  I decided to show it unprocessed to show how effective contrast enhancement can be on the other images.

Here is a processed version, which is over-processed.  It's quite difficult to apply very subtle processing without losing information:

The colours are somewhat improved, but some might say - over-saturated in places.  It's not easy!!

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