Thursday, July 23, 2015

Millipede Mating

I think this brings things full circle. Two weeks ago there was a barrage of baby pill bugs, last week we saw death occur as a hungry beetle larvae happened upon a slug, and this week we have millipede mating!


What we can see occurs over a period of 6 hours, and at some point it looks like three millipedes are involved. It's difficult to tell if they are the same millipedes participating throughout the entirety.

I had originally incorrectly titled this post "Centipede Mating". You can see between 16:02:01 and 16:57:02 that each body segment has two pairs of legs. If these were Centipedes you would only see one pair per segment. Assuming these are mating Millipedes we might get to see a slew of babies in a few weeks! Apparently they start off with only three pairs of legs and only after a few molting sessions do they appear as we're used to seeing them.

Amazing piece of info: Millipedes are part of the Myriapod family (many feet), and were the first oxygen breathing animal to walk on land! And last, these creatures are a significant contributor to decomposition, that crazy process that results in this wonderful pile of material we call soil that keeps you and I fed. Next time you're eating anything or simply going somewhere on a walk, thank the Millipedes.

 - https://en.wikipedia.org/wiki/Pneumodesmus
 - https://en.wikipedia.org/wiki/Myriapoda
 - http://www.biokids.umich.edu/critters/Myriapoda/

Image stabilization issues
Some of the videos I compile tend to shake left and right, a result of the scanner occasionally starting at a slightly different position. It always scans the same distance and looking at one image next to another it's difficult to see any difference. Play them back in a video and it becomes very apparent that the images don't line up.

I've used FFMPEG's deshake option to smooth out this jitter, but it's difficult to remove all of it. Going through each image one at a time is a bit too time consuming, so we need to either resolve the initial problem that causes it, or figure out a more accurate work around.

A few thoughts on resolving / working around this:
1. Figure out how the scanner returns home.
 - At 600 DPI even a millimeter off will result in a 20pixel shift. When viewing the whole 8.5x11" area it's not very obvious, when zooming into a smaller area it is. The intended use of these scanners from the manufacturer likely did not include building timelapse videos : )

2. Can we compare the first twenty rows of pixels from left to right of sequential images?
 - Once we find a certain percentage match, trim all rows to the left off.

3. Apply a ~5mm solid white border to the glass scanning plate
 - Use imagemagick to locate the border and crop within the boundary.

1 comment: