Dual-channel adaptive 2D noise reduction for video signals

A video image noise reduction system, comprising:

• a splitter that splits an input video image signal into a low-pass channel signal and a high-pass channel signal;
• a low-pass signal processor that processes the low-pass signal by adaptive directional filtering;
• a high-pass signal processor that processes the high-pass channel signal by nonlinear filtering;
• and
• a combiner that combines the processed low-pass signal and the processed high-pass signal to obtain a noise-reduced output image.

A method for reducing noise in video image signals, comprising the steps of:

• splitting an input video image signal into a low-pass channel signal and a high-pass channel signal;
• determining the channel noise levels for the low-pass channel and the high-pass channel;
• processing the low-pass signal by adaptive directional filtering based on the estimation of the local image 2D statistics, local image 1D statistics, the local image structure direction and the noise level of the low-pass channel;
• processing the high-pass channel signal by nonlinear filtering based on the estimation of said local statistics and the noise level of the high-pass channel;
• and
• summing the processed low-pass signal and the processed high-pass signal to obtain a noise-reduced output image.

A video image noise reduction system, comprising:

• a splitter that splits an input video image signal into a low-pass channel signal and a high-pass channel signal;
• a channel noise calculator that determines the channel noise levels for the low-pass channel and the high-pass channel;
• a low-pass signal processor that processes the low-pass signal by adaptive directional filtering based on the estimation of the local image 2D statistics, local image 1D statistics, the local image structure direction and the noise level of the low-pass channel;
• a high-pass signal processor that processes the high-pass channel signal by nonlinear filtering based on the estimation of said local statistics and the noise level of the high-pass channel;
• and
• a combiner that combines the processed low-pass signal and the processed high-pass signal to obtain a noise-reduced output image.