公开(公告)号：US20250008084A1

公开(公告)日：2025-01-02

申请号：US18710252

申请日：2022-11-08

Applicant: Nokia Technologies Oy

Inventor： Pekka ASTOLA ,  Jani LAINEMA

IPC: H04N19/105 ,  H04N19/132 ,  H04N19/167 ,  H04N19/176 ,  H04N19/186 ,  H04N19/463 ,  H04N19/50 ,  H04N19/85

Abstract: A method comprising: obtaining an image block unit comprising samples in color channels of unit comprising samples in color channels of one or two chrominance channels and one luminance channel (900); reconstructing samples of said luminance channel of the image block unit (902); predicting chrominance samples of at least one color channel of image block unit using at least two cross-component prediction models, each comprising their corresponding linear model parameters, and a luminance threshold value dividing the samples of said luminance channel between said at least two cross-component prediction models (904); defining a weighting function for said at least two cross-component prediction models based on location of said two or more chrominance samples and the luminance threshold value (906); and applying a smoothing function for samples residing within an offset value from said luminance threshold value, wherein said smoothing function adjusts chrominance values of said samples residing within said offset value by applying said weighting function on the corresponding at least two linear model parameters of the at least two cross-component prediction models (908).

公开(公告)号：US20250056017A1

公开(公告)日：2025-02-13

申请号：US18710679

申请日：2022-11-09

Applicant: Nokia Technologies Oy

Inventor： Ramin GHAZNAVI YOUVALARI ,  Pekka ASTOLA ,  Jani LAINEMA ,  Alireza AMINLOU

IPC: H04N19/176 ,  G06T7/40 ,  H04N19/147 ,  H04N19/186 ,  H04N19/70

Abstract: A method comprising: obtaining an image block unit comprising samples in color channels of one or two chrominance channels and one luminance channel: reconstructing samples of said luminance channel of the image block unit: determining parameters for at least one prediction model for predicting samples of at least one color channel of the image block unit using a prediction model based on one or more reference samples in a neighboring block in current channel/frame, one or more reference samples in a block neighboring a co-located block in a reference channel/frame; and one or more reference samples inside the co-located block in the reference channel/frame; and determining said at least one prediction model as a polynomial and/or exponential prediction model.

公开(公告)号：US20240292005A1

公开(公告)日：2024-08-29

申请号：US18574177

申请日：2022-06-07

Applicant: Nokia Technologies Oy

Inventor： Ramin GHAZNAVI YOUVALARI ,  Pekka ASTOLA

IPC: H04N19/196 ,  H04N19/132 ,  H04N19/159 ,  H04N19/176

CPC classification number: H04N19/196 ,  H04N19/132 ,  H04N19/159 ,  H04N19/176

Abstract: A method comprising: obtaining an image block unit comprising samples in color channels of one or two chrominance channels and one luminance channel (800); reconstructing samples of said luminance channels of the image block unit (802); predicting samples of at least one color channel of image block unit using a cross-component prediction model based on reconstructed samples on a reference channel, wherein parameters of the cross-component prediction model are determined at least partly based on a plurality of reconstructed chrominance samples and their corresponding reconstructed luminance samples in neighboring image block units (804); predicting a plurality of color channel samples in said neighboring image block units co-locating at least part of the reconstructed chrominance and luminance samples using said cross-component prediction model (806); determining a difference between values of the predicted plurality of color channel samples in said neighboring image block and corresponding reconstructed color channel samples (808); and adjusting the parameters of the cross-component prediction model based on said difference (810).

公开(公告)号：US20240064311A1

公开(公告)日：2024-02-22

申请号：US18259765

申请日：2021-12-17

Applicant: Nokia Technologies Oy

Inventor： Pekka ASTOLA ,  Alireza AMINLOU ,  Jani LAINEMA

IPC: H04N19/167 ,  H04N19/186 ,  H04N19/59

CPC classification number: H04N19/167 ,  H04N19/186 ,  H04N19/59

Abstract: The embodiments relate to a method comprising obtaining sample values of a target area in a picture to be encoded (310); obtaining sample values of a regressor area in a picture to be encoded (320); determining at least one set of prediction coefficients by means of a linear regression (330); predicting the sample values of the target area using the determined at least one set of prediction coefficients to result in a first predicted sample values (340); determining best performing set of prediction coefficients (350); predicting the sample values of the target area using the best performing set of prediction coefficients (360); encoding an indication indicating the best performing set of prediction coefficients along the bitstream (370), and iterating the steps for all target areas in the picture to be encoded (380). The embodiments also relate to a decoding method, and apparatuses for encoding and decoding.