Patent ID: 8175414

Claim:
A dynamic noise filter, comprising: a noise estimation circuit for calculating a noise mean (u) and a noise variance (v) according to maximum absolute luminance differences of estimation blocks associated with a plurality of pixels having the several lowest noise levels according, to a current image and its corresponding preceding image and performing noise estimation to generate a temporal attribute parameter and a spatial attribute parameter of the current image; a temporal noise reduction (TNR) filtering circuit for receiving the current image and its corresponding preceding image, modifying a first kink position in its own TNR characteristic curve at a minimum alpha value to form an updated TNR characteristic curve for the current image according to the temporal attribute parameter generated by the noise estimation circuit at the preceding image period and generating at least one first filtered scan line and a corresponding first parameter flow; a motion estimation circuit for providing both settings of pixels in a mosquito noise region and a movement amount of a mosquito noise block comprising a target pixel according to an input image and its corresponding preceding image when the mosquito noise block has a strong edge region, wherein when a difference between a maximum value and a minimum value of the mosquito noise block is greater than a threshold value, the mosquito noise block is expanded to the mosquito noise region and the mosquito noise block is regarded as having the strong edge region; a spatial noise reduction (SNR) filtering circuit for modifying a second kink position in its own SNR characteristic curve at a maximum gain value to form an updated SNR characteristic curve for the current image and for generating a second filtered scan line and a corresponding second parameter flow according to the spatial attribute parameter generated by the noise estimation circuit at the preceding image period, preceding outputs of the motion estimation circuit, and the at least one first filtered scan line and the corresponding first parameter flow; and a blending circuit for sequentially blending the second filtered scan line and one of the at least one first filtered scan line to generate an output scan line according to the corresponding second parameter flow.