Daewoo Electronics Co., Ltd.

Daewoo Electronics Corporation

Samsung Co., Ltd.

Hae-Mook Jung

Seong-Dae Kim

Jae-Gark Choi

Si-Woong Lee

Soon-Jae Cho

Gyu-Hwan Chang

Jong-Hwa Lee

Min-Sub Lee

Woi-Soo Park

Hyun-Duk Cho

Yi-Han Kim

A method and apparatus processes a video signal by selectively encoding and decoding a plurality of blocks included in the video signal. The encoding apparatus selects a plurality of processing blocks from a motion compensated error signal and decides position data of the processing blocks, wherein error values contained in the processing blocks are larger than the remaining error values and each of the position data of the processing blocks denotes a left top pixel position of each of the processing blocks. Then the apparatus transforms the processing blocks to a plurality of sets of transform coefficients and converts the plurality of sets of transform coefficients into a plurality of sets of quantized transform coefficients. The plurality of sets of quantized transform coefficients are combined with the position data of the processing blocks in order to provide an encoded signal.

Method and apparatus for selectively encoding/decoding a video signal

An apparatus, for use in a motion-compensated video signal encoder, for determining a predicted current frame based on a current frame and a previous frame of a digital video signal, including: a unit for selecting a number of pixels from the pixels contained in the previous frame; a unit for detecting a first set of motion vectors between the current and the previous frames, each of the first set of motion vectors representing a motion for each of the selected pixels; a unit for producing a second set of motion vectors for all of the pixels contained in the current frame by using the first set of motion vectors; and a unit for assigning the value of each of the pixels in the previous frame, which corresponds to one of the pixels in the current frame through one of the second set of motion vectors, as the value of the one of the pixels in the current frame.

Method and apparatus for encoding a video signal using pixel-by-pixel

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

Motion vectors are determined between a current frame and a preceding frame within a frame duration by employing a time-sharing multi-tier hierarchical motion estimation approach, wherein the candidate blocks being grouped into a multiple number of hierarchical search areas. The motion vector determination scheme is initiated by performing a motion estimation of a highest hierarchy for all of the search blocks; and an error function and a motion vector of the highest hierarchy are stored. Subsequently, motion-estimation of a lower hierarchy is performed for each of the selected search blocks which have the error functions greater than the threshold value of the highest hierarchy. In the next step, the error functions of the highest and the lower hierarchies are compared for each of the selected search blocks and a smaller error function is selected therefrom to thereby update each of the stored potential motion vectors with the motion vector corresponding to the selected error function. The updating process is repeated for the next hierarchies and the stored potential motion vectors are provided as the motion vectors of the current frame when updating process for the stored potential motion vector for a predetermined lowest hierarchy is accomplished or the frame duration is exhausted.

Method and apparatus for detecting motion vectors based on hierarchical

An apparatus, capable of improving the overall coding efficiency by encoding an image signal having a still object based on an improved object oriented coding technique, comprises a first detector for detecting a contour image signal placed at the boundary of the object within the image signal and for encoding the detected contour image signal, to thereby generate a first encoded image signal; a divider for dividing the image signal into a plurality of image blocks with a predetermined identical size; a second detector for detecting image blocks containing the contour image signal from the image blocks and for generating a reconstructed image block for each of the detected image blocks; an encoder, responsive to a selection signal corresponding to the type of the image blocks, for selectively encoding the reconstructed image blocks or the non-detected image blocks, to thereby produce a second encoded image signal; and a formatter for formatting the first and the second encoded image signals.

Apparatus for encoding an image signal having a still object

An apparatus for estimating motion vectors between a current frame and a reference frame of video signals employs a set of moving object patterns, each of the, moving object patterns representing a predetermined pattern of movement for at least one moving object and comprises; unit for storing the set of moving object patterns; unit for dividing the current frame into a multiplicity of search blocks of an identical size; unit for producing a search region from the reference frame corresponding to one of the search blocks; unit for producing a plurality of candidate blocks of the identical size in the search region; and unit for comparing the one of the search blocks with the plurality of candidate blocks in the search region on the basis of each of the moving object patterns to produce a codeword index for a selected moving object pattern and a motion vector representing the displacement of one of the moving object(s) defining the selected moving object pattern.

Apparatus for detecting motion vectors using moving object patterns

A blocking matching motion estimation apparatus estimates a displacement of a search block in a current frame with respect to each of candidate blocks in a previous frame to produce motion vectors and error signals representing the similarity between the search block and a candidate block. The motion estimating apparatus employs a weight function to weight a number of error signals based on a MSE measurement and selects a weighted error signal entailing a minimum error to produce a motion vector corresponding thereto. The weight function is determined by using either a local variance for a localized subblock defined for each pixel in the search block or a gradient of pixels in the search block filtered by a 2-dimensional gradient filter.

Block matching motion estimation apparatus employing a weight function

A method for encoding a block of video signal which includes a plurality of frames, each of the frames is divided into a multiplicity of nonoverlapping blocks and each of the blocks contains K.times.K pixels, K being a positive integer. The method determines two reconstruction values and a bit plane for the block, scans K.times.K binary pixels included in the bit plane in a zigzag order for providing run-length and level values, encodes the run-length and the level values by using a predetermined variable length coding table, thereby providing a coded bit plane, determines a selection signal denoting either the bit plane or the coded bit plane which is represented with a fewer number of bits; choosing either the bit plane or the coded bit plane in response to the selection signal, and combines the two reconstruction values, and either of the bit plane and the coded bit plane which was selected.

Method and apparatus for encoding a video signal by using a block

A method capable of improving the image quality comprises the steps of (a) detecting a motion vector for each search block in the current frame by using a block matching algorithm, (b) dividing a search block into a central region positioned at the center of the search block and a boundary region located outside the central region, (c) determining the motion vector for the search block as an optimum motion vector for the central region, and (d) determining a multiplicity of optimum motion vectors for the boundary region of the search block based on motion vectors for the search block and its one or more adjacent search blocks.

Motion compensation method for use in an image encoding system

An apparatus for encoding a digital video signal to provide a digitally coded video signal comprises a source coder for generating a set of quantized transform coefficients corresponding to each of the coding blocks, a scanning order determination block for adaptively determining a scanning order for each video frame based on a number of quantized transform coefficients having a non-zero value, located at a same pixel position in each of the coding blocks contained in a video frame and generating scanning order information representing the scanning order for each video frame, a scanner for scanning the set of quantized transform coefficients in response to the scanning order information to thereby generate scanned quantized transform coefficients, a statistical coder for statistically coding the scanned quantized transform coefficients to thereby generate statistically coded data, and a channel coder for encoding the statistically coded data together with the scanning order information to thereby generate digitally coded video signal.

Apparatus for encoding a digital video signal using an adaptive scanning

A method for determining motion vectors by employing a multi-tier hierarchical motion estimation comprises (a) motion-estimating each of the hierarchical search blocks of a processing block with respect to a corresponding hierarchical search region to thereby provide motion vectors and minimum error functions corresponding to hierarchical search blocks, (b) comparing the minimum error functions with a predetermined threshold, (c) determining a search block having a least minimum error function among the hierarchical search blocks; and (d) if minimum error functions of one or more search blocks are smaller than the predetermined threshold, determining as a motion vector of the processing block, a motion vector corresponding to a search block of a highest hierarchy among said one or more search blocks and if none of the minimum error functions are smaller than the predetermined threshold, determining a motion vector corresponding to the search block determined in said step (c) as a motion vector of the processing block.

Method for determining motion vectors using a hierarchical motion

A method, for use in a video signal encoding system, for processing a block of quantized transform coefficients first divides the block of quantized transform coefficients into a predetermined number of subblocks and detects one or more non-zero subblocks, each of the non-zero subblocks having at least one non-zero valued quantized transform coefficients therein. Thereafter, a predetermined sequence of the quantized coefficients is provided based on the detected non-zero valued subblocks, the provided sequence of the quantized transform coefficients consisting of all the coefficients within the non-zero subblocks. The predetermined sequence of the coefficients is then runlength and variable length coded for the transmission thereof.

Adaptive runlength coding based on zero and non-zero subblocks

A method for use in an object-oriented analysis-synthesis coder, for segmenting an image of a current frame into moving objects and describing each motion of the moving objects with a set of motion parameters, which comprises the steps of: (a) comparing the current frame with a preceding frame to detect a motion vector field; (b) sliding window blocks on the motion vector field, and computing the degree of homogeneity for each of the window blocks to produce a seed block; (c) determining a set of initial values for the set of motion parameters based on the seed block; (d) evaluating whether each motion vector contained in and around the seed block is describable with the set of initial values or not, to thereby detect a revised region; (e) determining a set of revised values for the set of motion parameters from the revised region; (f) evaluating whether each motion vector contained in and around the revised region is describable with the set of revised values or not, to thereby detect a newly revised region; and (g) repeating the steps (e) and (f) until the difference between a current revised region and a previous revised region is less than a predetermined value, to thereby determine a set of final values for the set of motion parameters.

Method for segmenting and estimating a moving object motion

A digital video signal encoder includes a discrete cosine transform and quantization circuit for generating a set of quantized transform coefficients corresponding to each of the coding blocks. The set of quantized transform coefficients is divided into a first and a second subsets of scanned quantized transform coefficients by a scanning circuit, the first subset including a predetermined number of quantized transform coefficients located on a predetermined low frequency zone and the second subset having the rest of quantized transform coefficients located on a high frequency zone. The first and the second set are transferred to a vector quantizer and a variable length coder, respectively. The variable length coder performs the statistical coding of the second subset of quantized transform coefficients to thereby generate statistically coded data; and vector quantizer performs the vector quantization of the first subset of scanned quantized transform coefficients to thereby generate vector quantized data.

Apparatus for encoding an image signal using vector quantization

A method, for use in an object-oriented analysis-synthesis coder, for segmenting an image signal into moving objects contained in a current frame and describing each motion of the moving objects with a set of motion parameters using a multi-stage segmentation comprises the steps of: (a) comparing the current frame with its preceding frame to detect a moving area in the current frame; (b) further comparing the current frame with the preceding frame to detect a motion vector for each pixel in the moving area, i.e., a motion vector field; (c) first segmenting the motion vector field by using a two dimensional translational patch model; (d) secondly segmenting the first stage segmenting results by using a planar patch model; and (e) thirdly segmenting the second-stage segmenting results by using a parabolic patch model.

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Seoul, South Korea

Hae-Mook Jung