Video denoising
Video denoising is the process of removing noise from a video signal. Video denoising methods can be divided into:
- Spatial video denoising methods, where [Noise reduction#In images|image noise reduction] is applied to each frame individually.
- Temporal video denoising methods, where noise between frames is reduced. Motion compensation 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.
Overview
Video denoising is done in two areas: they are chroma and luminance; chroma noise is where one sees color fluctuations, and luminance is where one sees 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 the following:
- Analog noise
- * Radio channel artifacts
- ** High-frequency interference
- ** Brightness and color channel interference
- ** Video reduplication – false contouring appearance
- * VHS artifacts
- ** Color-specific degradation
- ** Brightness and color channel interference
- ** Chaotic line shift at the end of frame
- ** Wide horizontal noise strips
- * Film artifacts
- ** Dust, dirt, spray
- ** Scratches
- ** Curling
- ** Fingerprints
- Digital noise
- * Blocking – low bitrate artifacts
- * Ringing – low and medium bitrates artifact, especially on animated cartoons
- * Blocks damage in case of losses in digital transmission channel or disk injury