Tuesday, April 2, 2019

Random obstructions

Yesterday I took this photo in Barcelona while waiting for the airport bus at Pla├ža d'Espanya:

Laura lamented the presence of the various lamp posts and traffic signals. Given the flatness of the sky, I though this was an ideal situation for some Snapseed photo editing. I loaded the above image into Snapseed and erased the various random obstructions. I also cropped it a bit and got this:


In the flat sky, they get wiped out pretty well, but you can still see the bottom parts of the posts. In more detailed parts of the photo, Snapseed doesn't work as effectively, so I usually just leave those bits alone and hope people don't notice.

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With daylight savings time resuming here in Spain over the weekend, were now back to 6 hours ahead of the east coast and 9 hours ahead of the west coast. The advancing spring and the changing sun angles make every evening along the river a little different:


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Speaking of random obstructions. Today I started coding an example algorithm I'm developing. In part of it, I need to generate random numbers according to a bi-variate density distribution. After looking around a bit on-line and getting what I thought were overly complicated solutions, I decided to take a shot at writing my own recipe. For a non-negative density function, r_values, with maximum, rmax, just do this:



Not sure if it's mathematically sound, but it does what I need.