Image noise is random (not present in the object imaged) variation of brightness or color information in images, and is usually an aspect of electronic noise. It can be produced by the sensor and circuitry of a scanner or digital camera. Image noise can also originate in film grain and in the unavoidable shot noise of an ideal photon detector. Image noise is an undesirable by-product of image capture that adds spurious and extraneous information.
The original meaning of "noise" was and remains "unwanted signal"; unwanted electrical fluctuations in signals received by AM radios caused audible acoustic noise ("static"). By analogy unwanted electrical fluctuations themselves came to be known as "noise". Image noise is, of course, inaudible.
The magnitude of image noise can range from almost imperceptible specks on a digital photograph taken in good light, to optical and radioastronomical images that are almost entirely noise, from which a small amount of information can be derived by sophisticated processing (a noise level that would be totally unacceptable in a photograph since it would be impossible to determine even what the subject was).
Read more about Image Noise: In Digital Cameras, Image Noise Reduction, Video Noise, Useful Noise, Low- and High-ISO Noise Examples
Famous quotes containing the words image and/or noise:
“Some days your hat’s off to the full-time mothers for being able to endure the relentless routine and incessant policing seven days a week instead of two. But on other days, merely the image of this woman crafting a brontosaurus out of sugar paste and sheet cake for her two-year-old’s birthday drives a stake through your heart.”
—Melinda M. Marshall (20th century)
“It is as real
as splinters stuck in your ear. The noise we steal
is half a bell. And outside cars whisk by on the suburban street
and are there and are true.
What else is this, this intricate shape of air?
calling me, calling you.”
—Anne Sexton (1928–1974)