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1. US20200186836 - Adaptive DCT Sharpener

Office United States of America
Application Number 16210900
Application Date 05.12.2018
Publication Number 20200186836
Publication Date 11.06.2020
Publication Kind A1
IPC
H04N 19/625
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
60using transform coding
625using discrete cosine transform
H04N 19/124
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
10using adaptive coding
102characterised by the element, parameter or selection affected or controlled by the adaptive coding
124Quantisation
H04N 19/184
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
10using adaptive coding
169characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
184the unit being bits, e.g. of the compressed video stream
CPC
H04N 19/184
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
10using adaptive coding
169characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
184the unit being bits, e.g. of the compressed video stream
H04N 19/625
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
60using transform coding
625using discrete cosine transform [DCT]
H04N 19/124
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
NPICTORIAL COMMUNICATION, e.g. TELEVISION
19Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
10using adaptive coding
102characterised by the element, parameter or selection affected or controlled by the adaptive coding
124Quantisation
Applicants Google LLC
Inventors Peyman Milanfar
Feng Yang
Sungjoon Choi
Title
(EN) Adaptive DCT Sharpener
Abstract
(EN)

Methods are provided for sharpening or otherwise modifying compressed images without decompressing and re-encoding the images. An overall image quality is determined based on the source of the compressed image, the quantization table of the compressed image, or some other factor(s), and a set of scaling factors corresponding to the image quality is selected. The selected scaling factors are then applied to corresponding quantization factors of the image's quantization table or other parameters of the compressed image that describe the image contents of the compressed image. The scaling factors of a given set of scaling factors can be determined by a machine learning process that involves training the scaling factors based on training images determined by decompressing and then sharpening or otherwise modifying a source set of compressed images. These methods can provide improvements with respect to encoded image size and computational cost of the image modification method.

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