Nippon Telegraph and Telephone Corporation

Inter-University Research Institute Corporation Research Organization of Information and Systems

Seishi Takamura

Atsushi Shimizu

Yoshiyuki Yashima

Hirohisa Jozawa

Kazuto Kamikura

Yukihiro Bandoh

Shohei Matsuo

Shiori Sugimoto

Masaaki Matsumura

Kazuya Hayase

Hiroshi Watanabe

Atsushi Sagata

Hiroshi Fujii

Hideaki Kimata

Takayuki Kurozumi

Yoko Sogabe

Cheng Yang

Gene Cheung

Yukihiro Bandou

An image coding method includes: an image acquisition step of acquiring a coding-target image; a feature map generation step of generating a feature map, based on the image; a contraction function generation step of performing fractal compression of the feature map and generating a contraction function; and an entropy encoding step of performing entropy encoding of the contraction function.

Image encoding method, image decoding method, image encoding apparatus, image decoding apparatus and program

An image encoding method that generates and encodes a gram matrix representing an image feature when encoding an image to be encoded includes a feature map generation step of generating a plurality of feature maps from the image to be encoded; a gram matrix generation step of generating a gram matrix through calculations between/among the feature maps; a representative vector determination step of generating a representative vector and a representative coefficient value by singular value decomposition of the gram matrix; and a vector encoding step of encoding the representative coefficient value and the representative vector.

Image encoding method and image decoding method

An image generation apparatus for generating a reference image that is referenced when encoding a time-series frame group that is a set of frames in which a second subject is captured so as to be temporally apparently deformed due to a property of a first subject comprises a reference image generation unit that generates the reference image in which a change in an image based on the property of the first subject is suppressed and apparent deformation of the second subject is suppressed.

Image generation apparatus, image generation method and program

An encoding method is performed by an encoding apparatus, and the encoding method includes a step in which an image of an object captured by a camera in a plurality of frames of a moving image is analyzed and it is determined whether camera parameters relating to an intrinsic matrix of the camera are invariable, a step in which, when the camera parameters are invariable, six parameters representing destinations of three points for a projective transformation unit of the image of the object are generated, and a homography matrix is generated on the basis of the six parameters, and a step in which projective transformation is performed on the projective transformation unit of the image of the object using the homography matrix, and a prediction signal of the image of the object is generated on the basis of the result of the projective transformation.

Encoding method, encoding apparatus, and program

A coding amount estimation device includes: a feature vector generation unit that generates a feature vector on the basis of a feature map generated by an estimation target image and at least one filter set in advance; and a coding amount evaluation unit that evaluates a coding amount of the estimation target image on the basis of the feature vector.

Encoding amount estimation apparatus, encoding amount estimation method and encoding amount estimation program

An image processing device that updates a pixel value of a processing target image and generates a new image generates a first feature vector based on the processing target image and a first feature map generated with at least one pre-decided filter; updates the processing target image to generate an updated image; generates a second feature vector based on the updated image and a second feature map generated with at least one pre-decided filter; performs quality evaluation of the updated image based on the first and second feature vectors and generates a quality feedback vector which is a vector based on a result of the quality evaluation; performs an encoding amount evaluation on the updated image and generates an encoding amount feedback vector which is a vector based on a result of the encoding amount evaluation; and determines an updating amount in updating of the updated image based on the quality feedback vector and the encoding amount feedback vector.

Image processing apparatus, image processing method and image processing program

A predictive image acquisition device is a predictive image acquisition device for associating an observation signal, the observation signal being a signal obtained from an original image serving as a decoding target image and being a lower dimensional signal than the original image, a first predictive image having a high correlation with the original image, and a second predictive image having a high correlation with the original image with each other to obtain a combined predictive image, and includes an interpolation factor acquisition unit configured to obtain an interpolation factor set for each pixel of the combined predictive image from the first predictive image, the second predictive image, and the observation signal, and a combined predictive image acquisition unit configured to combine the first predictive image and the second predictive image for each pixel using the interpolation factor to obtain the combined predictive image, and the pixels constituting the observation signal are expressed by a linear sum of the original image.

Prediction image acquisition apparatus, original signal acquisition apparatus, prediction image acquisition method and program

Regions based on which an interpolation method of a fractional-accuracy pixel is switched are optimized, and the interpolation method is switched for each of the divided regions, thereby reducing residual energy of inter-frame prediction with motion compensation. A video encoding apparatus is provided with: an encoding information acquiring unit which acquires encoding information for each block; a region classification unit which performs a region classification on a block-by-block basis in accordance with the encoding information; a divided region redefinition processing unit which shifts a region dividing line in a horizontal direction, a region dividing line in a vertical direction, or both the region dividing line in the horizontal direction and the region dividing line in the vertical direction based on a result of the region classification, and determines a region dividing line with which density of blocks belonging to a particular region classification is greater than or equal to a predetermined threshold value; an interpolation method switching unit which switches an interpolation method of a fractional-accuracy pixel for each of divided regions divided by the region dividing line; an interpolation performing unit which performs interpolation of the fractional-accuracy pixel for each of the divided regions; a picture encoding unit which encodes a picture using inter-frame prediction with motion compensation of fractional-accuracy for an interpolated picture; and a region classification information encoding unit which encodes information on the region classification.

Video encoding method, video decoding method, video encoding apparatus, video decoding apparatus, and programs thereof

Setting a reference pixel signal from a decoded pixel signal in intra-prediction in which a prediction signal is generated in the same frame, acquiring prediction mode identification information that identifies an intra-prediction mode, generating a prediction signal based on the reference pixel signal and the prediction mode identification information, making a determination regarding correction of the prediction signal using a reference pixel having a shorter distance from a pixel that is a prediction target in the intra-prediction mode identified by the prediction mode identification information, and correcting the generated prediction signal according to a result of the determination are included in order to provide an image encoding method and an image decoding method capable of improving subjective image quality and coding efficiency using a closer decoded pixel in an intra-prediction process.

Intra-prediction encoding method, intra-prediction decoding method, intra-prediction encoding apparatus, intra-prediction decoding apparatus, program therefor and recording medium having program recorded thereon

A video encoding device uses motion-compensated inter-frame prediction by dividing an image into blocks, each block a predetermined size, designating a first component value of a plurality of component values of a motion vector (MV) between an encoding target block and a neighboring block, designating a second component value, and encoding each first and second component values; a first component encoding means encodes a difference value of a first component and a second component encoding means, which obtains a probability of occurrence of a candidate value for the second component value of the MV of the encoding target block, based on a difference value between the first component value of the neighboring block MV and the first component value of the encoding target block MV and the second component value of the neighboring block MV, specifies a codeword of the second component value, encoding it based on the occurrence probability.

Video encoding device, video decoding device, video encoding method, video decoding method, and non-transitory computer-readable recording media that use similarity between components of motion vector

The prediction error energy in inter-frame prediction with motion compensation is reduced and the coding efficiency is improved. A video encoding method using fractional-accuracy motion compensation includes: a step of generating multiple weighted filter coefficients from multiple interpolation filter sets using weight parameters which designate weight values of interpolation filter coefficients; a step of selecting weighted filter coefficients which minimize prediction error energy in the fractional-accuracy motion compensation from among the weighted filter coefficients; a step of interpolating fractional-accuracy pixels for a reference picture by application of an interpolation filter with the selected weighted filter coefficients and encoding an input picture with the fractional-accuracy motion compensation; and a step of encoding the weight parameters used for generating the selected weighted filter coefficients and the interpolation filter coefficients and adding encoded weight parameters and encoded interpolation filter coefficients to an encoded bitstream.

Method and apparatus for encoding video, method and apparatus for decoding video, and programs therefor

A reduction in residual energy of inter-frame prediction with motion compensation and improvement in encoding efficiency are achieved by using a region-dividing type adaptive interpolation filter that takes an edge property of a picture into consideration. An edge calculation unit calculates edge information from reference picture data designated by a motion vector. A region dividing unit divides an encoding target frame into a plurality of regions that are units to which interpolation filters are adaptively applied based on the edge information. A filter coefficient optimizing unit optimizes an interpolation filter for a fractional-accuracy pixel for each of the regions. A reference picture interpolating unit interpolates the fractional-accuracy pixel of a reference picture using the optimized interpolation filter, and a predictive encoding unit performs predictive encoding using motion compensation of fractional-accuracy.

The computational complexity of a denoising filter is reduced while suppressing a reduction in coding efficiency. In a video encoding/decoding apparatus which uses a loop filter, a deviation degree calculating unit calculates the degree of deviation between a denoising target pixel and a surrounding pixel using a decoded image. A template shape setting unit limits a template shape so that its size is proportional to the degree of deviation relative to the maximum value of the degree of deviation in the decoded image. When noise of the target pixel is removed, weighted in accordance with the degree of similarity between a template of the target pixel and a template of each of search points in a search shape and the weighted sum of pixel values at the search points, the loop filter performs template matching using the limited template shape and removes noise of the target pixel.

Video encoding/decoding methods, video encoding/decoding apparatuses, and programs therefor

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

In an image processing apparatus, an edge direction detection unit calculates an edge direction using a denoising target image. A search shape setting unit sets a search shape in which the number of search points along the direction perpendicular to the edge direction is smaller than the number of search points along the edge direction, using the calculated edge direction as an index used for limiting the search shape. When noise of a target pixel is removed with a weight in accordance with the degree of template similarity between a template for the target pixel and a template for each of search points within a search shape and the weighted sum of pixel values at the search points, a filter execution unit executes a process of performing template matching on only search points within the set search shape and removing the noise of the target pixel.

Image processing method, image processing apparatus, video encoding/decoding methods, video encoding/decoding apparatuses, and non-transitory computer-readable media therefor that perform denoising by means of template matching using search shape that is set in accordance with edge direction of image

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Yokosuka, Japan

Seishi Takamura