Patent ID: 7522220
Filing Date: 2009-04-21
Classification: G06K,G06T

Abstract:
1. 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; processing the low-pass signal by adaptive directional filtering processing the high-pass channel signal by nonlinear filtering; combining the processed low-pass signal and the processed high-pass signal to obtain a noise-reduced output image; estimating the local image statistics; wherein the step of processing the low-pass signal further includes the steps of processing the low-pass signal by adaptive directional filtering based on the estimated local image statistics and the noise level of the low-pass channel, and the step of processing the low-pass signal by adaptive directional filtering further includes the steps of: computing the local 2D and 1D statistics; detecting the local image structure direction; generating a 1D adaptive directional filter using the calculated 1D statistics and the low-pass channel noise level; and obtaining a 2D filtered result from the low-pass signal using the 2D statistics; obtaining a 1D adaptive directional filtered result from the from the low-pass signal using the 1D adaptive directional filter; and combining the 2D mean result and the 1D adaptive directional filter result to obtain the processed low-pass channel output signal.