Video denoising is the process of removing
noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference aris ...
from a
video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...
signal. Video denoising methods can be divided into:
* Spatial video denoising methods, where
image noise reduction
Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree. Noise rejection is the ability of a circuit to isolate an und ...
is applied to each
frame individually.
* Temporal video denoising methods, where noise between frames is reduced.
Motion compensation
Motion compensation in computing, is an algorithmic technique used to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. It is employed in the encoding of video d ...
may be used to avoid ghosting artifacts when blending together pixels from several frames.
* Spatial-temporal video denoising methods use a combination of spatial and temporal denoising. This is often referred to as 3D denoising.
It is done in two areas:
They are chroma and luminance, chroma noise is where one see color fluctuations and luminance is where one see light/dark fluctuations. Generally, the luminance noise looks more like film grain while chroma noise looks more unnatural or digital like.
Video denoising methods are designed and tuned for specific types of noise.
Typical video noise types are following:
*
Analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
noise
**
Radio channel
Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio sta ...
artifacts
*** High frequency interference (dots, short horizontal color lines, etc.)
*** Brightness and color channel interference (problems with antenna)
*** Video reduplication – false contouring appearance
**
VHS artifacts
*** Color-specific degradation
*** Brightness and color channel interference (specific type for VHS)
*** Chaotic line shift at the end of frame (lines resync signal misalignment)
*** Wide horizontal noise strips (old VHS or obstruction of magnetic heads)
** Film artifacts (''see also
Film preservation
Film preservation, or film restoration, describes a series of ongoing efforts among film historians, archivists, museums, cinematheques, and non-profit organizations to rescue decaying film stock and preserve the images they contain. In the wid ...
'')
*** Dust, dirt, spray
***
Scratches
*** Curling (emulsion exfoliation)
***
Fingerprint
A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfac ...
s
*
Digital
Digital usually refers to something using discrete digits, often binary digits.
Technology and computing Hardware
*Digital electronics, electronic circuits which operate using digital signals
** Digital camera, which captures and stores digital ...
noise
**
Blocking – low bitrate artifacts
** Ringing – low and medium bitrates artifact especially on animated cartoons
** Blocks (slices) damage in case of losses in digital transmission channel or disk injury (scratches on DVD)
Different suppression methods are used to remove all these artifacts from video.
See also
*
Image denoising
References
External links
Reduce noise in video
{{DEFAULTSORT:Video denoising
Noise reduction
Video
Video processing
Video signal