Sucking out the atmosphere

[mattbell]

The view from an aircraft is incredible, but the atmospheric haze even on clear days dramatically reduces the contrast.  However, I realized that, mathematically speaking, the haze is adding a constant amount of light to each pixel of the image.  (The blue haze that occurs in absence of air pollution or atmospheric particulate matter comes primarily from Rayleigh scattering.  Rayleigh scattering is also the answer to the childhood question "Why is the sky blue?)  I can estimate the color value of this haze by finding a particularly dark part of the image and assuming that the actual object there is black.  Then, I can subtract that value from every pixel.  The results are dramatic:

Before:



After:



More pairings:

Bay bridge construction:



A reservoir:



Some hills:



If I really want to do this right, I should take multiple black samples to account for the fact that there is a greater distance (and thus more haze) in the top parts of the photo than there is at the bottom.  Then I can make a gradient in Photoshop between the two values. 

Comments

[nasu-dengaku.livejournal.com]

Those are fantastic!

[agentsteel53.livejournal.com]

thanks :)

I tend to do a lot of levels adjustment on the shadow end to fix contrast problems, whether due to windshields, airplane windows, or the lens itself losing contrast.