Types of noise There are two different types of noise found in digital images. Luminance noise shows up as a speckled pattern, like specks of black sand, and is similar to the grain that was found when using high-ISO black-and-white films. Chromatic noise is coloured and looks like the rainbow-like sheen when looking at a patch of oil (and is similar in appearance to the blotchy dye patterns that you saw when enlarging high-ISO colour films). CHROMATIC Colour, or ‘chroma’ noise is a multicoloured speckling, where neighbouring pixels show random colour variations. This is quite easy for noise reduction processes to remove without harming image detail, and you tend to see it on older cameras. LUMINANCE Luminance noise is caused by random variations in brightness between pixels and it’s harder to deal with because noise reduction processes can’t readily distinguish noise from real detail. Reducing it will usually have an effect on fine detail too. You can see examples of both in the infographics below. source : digitalcameraworld/2014/02/19/what-is-iso-camera-sensitivity-settings-and-the-best-ways-to-use-them/3/
Posted on: Sat, 27 Sep 2014 03:46:27 +0000