Patent ID: 8385425
Filing Date: 2013-02-26
Classification: H04N

Abstract:
1. A method to be executed at least in part in a computing device for temporal filtering of video signals employing sign-based pixel difference classification, the method comprising: receiving two sequential video frames comprising a current frame and an immediately previous frame; comparing pixel values of a block of pixels in the current frame with pixel values of a corresponding block of pixels in the immediately previous frame; from the comparison, identifying differences in values between the pixel values of the block of pixels in the current frame with the pixel values of the corresponding block of pixels in the immediately previous frame, wherein the values include a magnitude and a sign; from the identified differences in the values, creating a corresponding block of signs associated with the differences in the values identified between the pixel values of the block of pixels within the current frame and the values of the corresponding block of pixels in the immediately previous frame; determining a randomness of a distribution of the signs in the corresponding block of signs associated with the differences in the values identified between the pixel values of the block of pixels within the current frame and the pixel values of the corresponding block of pixels in the immediately previous frame; based on the randomness of the distribution of the signs in the corresponding block of signs, classifying the block of pixels within the current frame as one of a background and non-moving foreground block of pixels if the randomness meets a predefined criterion; if the block of pixels within the current frame is one of a background and non-moving foreground block, performing recursive temporal filtering on the block of pixels within the current frame, otherwise not filtering the block of pixels within the current frame; performing the comparing pixel values of the block of pixels in the current frame with pixel values of the corresponding block of pixels in the immediately previous frame, identifying differences in the values between the pixel values of the block of pixels in the current frame with the pixel values of the corresponding block of pixels in the immediately previous frame, creating a corresponding blocks of signs associated with the differences in the values identified between the pixel values of each of the block of pixels within the current frame and the values of each of the corresponding block of pixels in the immediately previous frame, determining the randomness of a distribution of the signs in each of the corresponding block of signs, classifying each of the block of pixels within the current frame based on the randomness of the distribution of the signs in the corresponding block of signs and filtering on each block of pixels within the current frame when classified as one of a background and non-moving foreground block for all blocks in the current frame; and encoding the classified and partially filtered frame for subsequent transmission to a video rendering application.