O'Reilly logo

The Low Light Photography Field Guide by Michael Freeman

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Noise-Reduction Software

So far, I’ve concentrated on how noise occurs, what it looks like, and the problems of detecting it. With all types of noise-reduction software, there are two principal steps.

The first is detection, selecting those pixels considered to be rogue artifacts. The second, which we’ll now look at, is the procedure for replacing them. At pixel level, noise is not simply removed, because that would leave a pattern of “holes,” whatever their color. It has to be replaced with values that blend it into its surroundings. The simplest way is to use a blurring filter, which has the effect of smearing the pixel values over a chosen radius. A Gaussian Blur filter is the standard, default means of digital blurring, although for noise ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required