Nippon Telegraph and Telephone Corporation

Nagoya University

Yoshiyuki Yashima

Kazuto Kamikura

Shinya Shimizu

Hideaki Kimata

Seishi Takamura

Masaki Kitahara

Yukihiro Bandoh

Kazuya Hayase

Masayuki Tanimoto

Toshiaki Fujii

Kenji Yamamoto

Shohei Matsuo

Masaaki Matsumura

Yukihiro Bandou

A scalable video encoding method of performing encoding by predicting an upper-layer signal having a relatively high spatial resolution by means of interpolation using an immediately-lower-layer signal having a relatively low spatial resolution. The method computes a first weighting coefficient for each image area of a predetermined unit size in a search for estimating a motion between an encoding target image area in an upper layer and a reference image area, where the first weighting coefficient is computed based on a brightness variation between an image area, which belongs to an immediately-lower layer and has the same spatial position as the encoding target image area, and the reference image area; and performs a motion estimation using a signal which is obtained by correcting a decoded signal of the reference image area by the first weighting coefficient and functions as an estimated signal in the motion estimation, so as to compute a motion vector. Then the method computes a second weighting coefficient based on a brightness variation between a reference image area indicated by the motion vector and the image area which belongs to the immediately-lower layer and has the same spatial position as the encoding target image area; and determines a signal, which is obtained by correcting a decoded signal of the reference image area by using the second weighting coefficient, to be a compensated signal in motion compensation, which functions as a predicted signal of the encoding target image area.

Scalable video encoding method and decoding method, apparatuses therefor, programs therefor, and storage media which store the programs

An automatic producing method for a predicted value generation procedure that predicts a value of an encoding target pixel by using a previously-decoded pixel. A parent population is generated by randomly producing predicted value generation procedures each of which is indicated by a tree structure, and a plurality of predicted value generation procedures are selected as parents from the parent population. One or more predicted value generation procedures are generated as children based on a predetermined tree structure developing method which subjects the selected predicted value generation procedures to a development where an existing predicted value generation function can be an end node of a tree. A predicted value generation procedure having a best estimation cost is selected from among the predicted value generation procedures as the parents and children, where the sum of an information content for representing the tree structure and an amount of code evaluated by a predicted pixel value obtained by the tree structure is used as an estimation cost. A final predicted value generation procedure is produced by iterating the relevant operation.

Predicted pixel value generation procedure automatic producing method, image encoding method, image decoding method, apparatus therefor, programs therefor, and storage media which store the programs

A video encoding method for encoding a plurality of images as a video image. The method includes a reference parallax data setting step of setting reference parallax data which indicates a viewing difference between a first image and an already-encoded second image, in order to encode target encoding data assigned to a predetermined position in the first image; a corresponding position setting step of setting a corresponding position in the second image, which can correspond to the predetermined position, by using the reference parallax data; a code table setting step of setting a code table corresponding to target encoding data assigned to the corresponding position; and a target encoding data encoding step of encoding the target encoding data in the first image by using the code table.

Video encoding method and apparatus, video decoding method and apparatus, programs therefor, and storage media for storing the programs

A video encoding method for generating, based on disparity information between an already-encoded reference camera image and an encoding target camera image corresponding to the reference camera image, a disparity-compensated image by means of inter-camera image prediction; and encoding a differential image between the encoding target camera image and the disparity-compensated image. The method includes selecting, for each predetermined section unit on the differential image, one of a decoded differential image group obtained by decoding a differential image between the already-encoded camera image and the disparity-compensated image and a decoded camera image group obtained by decoding the already-encoded camera image, by determining whether or not there is a disparity-compensated image at the corresponding position, that is, whether or not the corresponding pixel in the disparity-compensated image has an effective value.

Video encoding method and decoding method, apparatuses therefor, programs therefor, and storage media which store the programs

A video encoding method, in which a video signal consisting of two or more signal elements is targeted to be encoded, includes a step of setting a downsampling ratio is set for a specific signal element in a frame, in accordance with the characteristics in the frame; and a step of generating a target video signal to be encoded, by subjecting the specific signal element in the frame to downsampling in accordance with the set downsampling ratio. The frame may be divided into partial areas in accordance with localized characteristics in the frame; and a downsampling ratio for a specific signal element in these partial areas may be set in accordance with the characteristics in each partial area.

Video encoding method and decoding method, apparatuses therefor, programs therefor, and storage media for recording the programs

A method for encoding an image using an intraframe prediction is provided which includes selecting a gradient of a pixel value that is indicated by an image signal to be predicted among a plurality of gradient candidates, generating a predicted signal by applying a gradient in accordance with the distance from a prediction reference pixel based on the gradient, intraframe-encoding the image signal to be predicted based on the predicted signal, and encoding information indicating the size of the selected gradient. Alternatively, the method includes estimating the gradient of a pixel value that is indicated by an image signal to be predicted based on an image signal which has already been encoded, generating a predicted signal by applying a gradient in accordance with the distance from a prediction reference pixel based on the gradient, and intraframe-encoding the image signal to be predicted based on the predicted signal.

Image encoding and decoding apparatuses, image encoding and decoding methods, programs thereof, and recording media recorded with the programs

When video images are processed by applying temporal or spatial interframe prediction encoding to each divided area, and generating a predicted image of a processing target area based on a reference frame of the processing target area and reference information which indicates a predicted target position of the processing target area in the reference frame, predicted reference information is generated as predicted information of the reference information. Reference information used when an area adjacent to the processing target area was processed is determined as predicted reference information prediction data used for predicting the reference information of the processing target area. Reference area reference information is generated using one or more pieces of reference information used when a reference area indicated by the prediction data was processed. The predicted reference information prediction data is updated using the reference area reference information. The predicted reference information is generated using one or more pieces of the updated predicted reference information prediction data.

Predicted reference information generating method, video encoding and decoding methods, apparatuses therefor, programs therefor, and storage media which store the programs

A video encoding method includes selecting a reference vector target frame and a reference frame from among already-encoded frames; encoding information for designating each frame; setting a reference vector for indicating an area in the reference vector target frame with respect to an encoding target area; encoding the reference vector; performing a corresponding area search by using image information of a reference vector target area, which belongs to the reference vector target frame and is indicated by the reference vector, and the reference frame; determining a reference area in the reference frame based on the search result; generating a predicted image by using image information of the reference frame, which corresponds to the reference area; and encoding differential information between image information of the encoding target area and the predicted image.

A video encoding method for encoding video images as a single video image by using parallax compensation which performs prediction by using parallax between the video images, and a corresponding decoding method. The number of parameters as parallax data used for the parallax compensation is selected and set for each reference image. Data of the set number of parameters is encoded, and parallax data in accordance with the number of parameters is encoded. During decoding, parallax-parameter number data, which is included in encoded data and designates the number of parameters as parallax data for each reference image, is decoded, and parallax data in accordance with the number of parameters is decoded, where the parallax data is included in the encoded data.

Video encoding method and decoding method by using selected parallax for parallax compensation, apparatuses therefor, programs therefor, and storage media for storing the programs

In a video scalable encoding method, based on encoding information of an immediately-lower image region in an immediately-lower layer, which is present at spatially the same position as an encoding target image region, a data structure of the weight coefficient, that includes a proportional coefficient and an offset coefficient, is determined. When the immediately-lower image region performed interframe prediction in the immediately-lower layer, the method identifies an immediately-lower layer reference image region that the immediately-lower image region used as a prediction reference for motion prediction, and calculates the weight coefficient by applying a weight coefficient that the immediately-lower image region used in weighted motion prediction to a DC component of an image region in the upper layer, which is present at spatially the same position as the immediately-lower layer reference image region, and assuming a result of the application as a DC component of the immediately-lower image region.

Video scalable encoding method and decoding method, apparatuses therefor, programs therefor, and recording media where programs are recorded

An image encoding method for encoding a pixel value of an encoding target by using a predicted value generated by spatial or temporal prediction using a previously-decoded image. The method performs prediction of the pixel value of the encoding target and obtains the predicted value; computes data of a probability distribution which indicates what value an original pixel value has for the obtained predicted value, by shifting, in accordance with the predicted value, difference distribution data of a difference between the original pixel value and the predicted value in predictive encoding, where the difference distribution data is stored in advance; clips the obtained data of the probability distribution so as to contain the data in a range from a lower limit to an upper limit for possible values of the original pixel value; and encodes the pixel value of the encoding target by using the clipped data of the probability distribution of the original pixel value from the lower limit to the upper limit.

In scalable video encoding, incidence rates of combinations of optimum prediction modes to be selected for spatially corresponding blocks of an upper layer and a lower layer are determined based on an optimum prediction mode that was selected in a conventional encoding, and then a correspondence table that describes relationships therebetween is created. Subsequently, the combinations of the selected optimum prediction modes described in the correspondence table are narrowed down based on the value of the incidence rate so as to create prediction mode correspondence information that describes the combinations of the optimum prediction mode narrowed down. When encoding the upper layer block, the prediction mode search candidate that is to be searched in the encoding is decided by referring to the prediction mode correspondence information using as a key the optimum prediction mode selected in the encoding of the spatially corresponding lower layer block and thereby reducing the number of the prediction mode search candidates.

Scalable video encoding method, scalable video encoding apparatus, scalable video encoding program, and computer readable recording medium storing the program

A video encoding method includes setting candidates for reference pixels to pixels within a predetermined distance range measured from an encoding target block; generating a predicted signal by sequentially selecting reference pixels used for the intra prediction of the encoding target block from among the reference pixel candidates while changing a distance condition from the encoding target block, and by generating the predicted signal based on the reference pixels for each distance condition; computing an encoding cost required for subjecting the encoding target block to intra prediction encoding using each generated predicted signal; finally determining reference pixels used for the intra prediction of the encoding target block based on each computed encoding cost; and encoding information which indicates the position of the determined reference pixels.

By using parallax compensation which performs prediction by using parallax between video images, the video images are encoded as a single video image. Reference parallax for a target image to be encoded is set, wherein the reference parallax is estimated using a reference image; area division in an image frame is set; parallax displacement for each divided area is set, wherein the parallax displacement is the difference between the reference parallax and parallax for the parallax compensation; data of the area division is encoded; and data for indicating the parallax displacement is encoded. During decoding, reference parallax for a target image to be decoded is set, wherein it is estimated using a reference image; data for indicating area division, which is included in encoded data, is decoded; and data of parallax displacement, which is included in the encoded data, is decoded for each area indicated by the area division data.

Video encoding method and decoding method, apparatuses therefor, programs therefor, and storage media for storing the programs by using parallax compensation

Growing community of inventors

Yokosuka, Japan

Yoshiyuki Yashima