Multiple exposures 18 in total for long exposure effect

Started 9 months ago | Discussions thread
AudiiDudii Contributing Member • Posts: 527
Re: Median vs average

JimKasson wrote:

Greg7579 wrote:

I am probably embarrassing myself here, but how does this remove the crowds?

Consider one pixel of a four images. One has part of a person in it. The other three does not. Say the part of the person is pure, bright red (255,0,0). Say the same place where the person is not is middle grey (127, 127,127). The median of the four frames is (127,127, 127). It's as if the person were never there.

In camera systems use averaging, because median processing is too computationally expensive. The average value for the above pixel is (159, 127,127). A red ghost of the person remains.

For the benefit of those who don't already know this, median blending is also great for reducing the amount of noise in long-exposure photos for the same reason it works to eliminate people ... two stones / one bird!  Or something like that...

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