Daewoo Electronics Co., Ltd.

Min-Sub Lee

Hae-Mook Jung

An apparatus for encoding a digital video signal to reduce a transmission rate of the digital video signal, which comprises a feature point based motion compensation circuit for selecting a set of feature points from the reconstructed reference frame to detect a set of motion vectors between a current frame and a original reference frame corresponding to the set of feature points by using a feature point based motion estimation, and for generating a second predicted frame based on the set of motion vectors and the reconstructed reference frame. The feature point based motion estimation employs a convergence process in which a displacement of each of the feature points are given to a motion vector thereof and the six triangles of each of the hexagon are affine-transformed independently using the displacements of their vertex feature points. If the displacements provide a better PSNR, the motion vector of the subject feature point is sequentially updated. Therefore, the inventive convergence process is very efficient in the matching process to determine the predicted image as close as possible to the original image having zooming, rotation or scaling of objects.

Method and apparatus for encoding a video signal using feature point

A method for determining feature points comprises a step for (a) providing directional gradients and a gradient magnitude for each pixel in the video frame, (b) normalizing the directional gradients by dividing the directional gradients with the gradient magnitude, (c) generating a first edge map having the gradient magnitude for each pixel, (d) generating a second edge map having the normalized direction gradients for each pixel, (e) dividing the first edge map into a plurality of blocks of an identical size, (f) providing, for each of the pixels included in each of the blocks, normalized directional gradients for a set of a predetermined number of pixels from the second edge map, (g) obtaining a variance for each of the pixels included in each of the blocks based on the provided normalized directional gradients, (h) determining a feature point for each of the blocks based on the gradient magnitude and variance corresponding to each of the pixels therein.

Method and apparatus for determining feature points

An image processing system for processing a video signal includes an encoder and a decoder, wherein the encoder comprises a frame decimator for selecting a plurality of frames from the video signal, a unit for creating M number of candidate frames for each of the non-selected frames, i.e., skipped frames by using M number of skipped frame prediction factors, and a unit for comparing each of the N skipped frames with each of the candidate frames to transmit a skipped frame prediction factor for each of the N skipped frames to the decoder; and the decoder comprises a unit for deciding each of the N skipped frames between the previous frame and the reconstructed current frame by using the transmitted skipped frame prediction factor.

Image processing system using pixel-by-pixel motion estimation and frame

A video signal encoding apparatus determines quasi-feature points on the current frame based on selected feature points on the previous frame. A predicted current frame is obtained based on a number of triangle regions formed by the quasi-feature points. After determining a frame difference signal by subtracting the predicted current frame signal from the current frame signal, a plurality of processing regions are selected from the frame difference signal based on the magnitude of average pixel difference values corresponding to the triangle regions. Only the selected processing regions are then encoded for transmission to thereby reduce a transmission rate. A video signal decoding apparatus comprises corresponding circuits for decoding the selectively encoded video signal.

Method and apparatus for encoding/decoding a video signal

An inventive apparatus determines true motion vectors between a current and its previous frames for feature points selected from the previous frame wherein a selected feature point is surrounded by its neighboring four feature points to form a previous rhombus having a set of four triangles based on the selected feature point. A motion vector displacement generator gives a predetermined N number of displacements to an initial motion vector for its corresponding feature points to thereby produce a subset of N candidate motion vectors and a motion prediction block provides a current rhombus corresponding to the previous rhombus by the initial motion vectors, wherein the current rhombus has N sets of four triangles due to the N candidate motion vectors. A true motion vector is selected from the subset of N candidate motion vectors, which entails a minimum error value between the predicted pixel values for each triangle set in the current rhombus and their respective corresponding current pixel values from the previous frame.

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Seoul, South Korea

Min-Sub Lee