METHOD FOR ENCODING A VIDEO SIGNAL USING FEATURE POINT BASED MOTION ESTIMATION

A method for adaptively selecting feature points according to motions of objects between the current frame and the previous frame, comprising the steps of: subtracting a pixel value of the previous frame from a pixel value of the current frame to thereby provide a differential pixel value; comparing the differential pixel value with a first threshold value TH1 and selecting processing regions having differential pixel values larger than the first threshold value TH1; detecting a motion vector for each pixel of the processing region in the previous frame; providing a pixel value of the current frame based on the motion vector for each pixel of the processing region in the previous frame; subtracting a pixel value of said each pixel of the processing region in the previous frame from the pixel value of the current frame to thereby provide an error pixel value; comparing the error pixel value with a second threshold value TH2 and selecting grid regions having error pixel values larger than the second threshold value TH2; generating a first grid for each of the processing regions in the previous frame and generating a second grid for said each of the grid regions; detecting edge points from the previous frame; and selecting, as the feature points, a multiplicity of pixels in the previous frame based on the first and the second grids and the edge points.