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Video denoising is the process of removing noise from a video signal. Video denoising methods are divided into:
- Spatial video denoising methods, when only one frame is used for noise suppression. Such methods are close to image noise reduction.
- Temporal video denoising methods, when only temporal information is used. Such method can be divided into:
- Motion adaptive methods - some analysis of pixel motion detection is used. If there is no motion in some pixels - serious averaging with previous pixels are used. In case of motion more accurate averaging required to avoid "ghosting" artifacts.
- Motion compensative methods use motion estimation to predict and consider right pixel values from correct place from previous frame(s). This method requires more time, but produce better results.
- Spatial-Temporal video denoising methods use a combination of spatial and temporal denoising.
Video denoising methods are designed and tuned for specific types of noise. Typical video noise types are following:
- Analog noise
- Radio channel 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)
- 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.
[edit] See also
