Thursday, June 20, 2013

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

1000 page views!!
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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