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:
“The essence of the physicality of the most famous blonde in the world is a wholesome eroticism blurred a little round the edges by the fact she is not quite sure what eroticism is. This gives her her tentative luminosity and what makes her, somehow, always more like her own image in the mirror than she is like herself.”
—Angela Carter (1940–1992)
“Places where he might live and die and never hear of the United States, which make such a noise in the world,—never hear of America, so called from the name of a European gentleman.”
—Henry David Thoreau (1817–1862)