Noise estimation and reduction apparatus for video signal processing
AssigneeThomson Licensing
InventorsRobert Norman Hurst, Jr., Jungwoo Lee
Life of this patent
Estimating the term…
Abstract
Video signal compression apparatus generates residues representing pixel value differences between predicted and real pixel values of a current frame of a video signal. Noise reduction circuitry, in the form of nonlinear processing functions, attenuates lower amplitude residues greater than higher amplitude residues and is responsive to a noise estimate. The processed residues are transformed to provide a compressed video data output. The nonlinear processing functions attenuate noise and reduce image distortion.
Claims21
Apparatus for compressing an image representative video signal containing pixel data comprising:
- means for estimating noise in said video signal and providing an output;
- means for generating residues having lower and higher amplitude components, said residues representing differences of pixel values between predicted pixel values and real pixel values of a current frame of said video signal being compressed;
- nonlinear processing means, coupled to said generating means, for attenuating lower amplitude residues greater than higher amplitude residues and providing processed residues at an output, wherein a transfer function of said nonlinear processing means is responsive to said noise estimate;
- and
- transform means for transforming said processed residues and providing a compressed video data output.
Apparatus for filtering noise in a signal comprising:
- an input processor for receiving and processing said signal to provide an output suitable for filtering;
- and
- a nonlinear processing means, coupled to said input processor, for attenuating lower amplitude components of said processed output more than higher amplitude components and for providing a filtered output, wherein the transfer function of said nonlinear processing means is in the class of coring functions, having a coring window, that substantially provide:
- (a) an identity function, in which the output is equal to the input, outside said coring window;
- and
- (b) a convex-downward and continuously increasing function inside said coring window.
Video signal compression apparatus comprising:
- means for estimating noise in a video signal and providing an output;
- nonlinear processing means for adaptively filtering said video signal with a coring function and providing a filtered video output signal, said coring function substantially providing a convex-downward and continuously increasing function inside a coring window of said coring function, wherein said coring function is responsive to said noise estimate;
- and
- transform means for compressing said filtered video output signal to provide a compressed video data output.
Dependencies are inferred from the claim text.