US 12,355,957 B2Granted

Temporal filter

AssigneeTelefonaktiebolaget LM Ericsson (publ)

InventorsPer Wennersten, Christopher Hollmann, Jacob Ström

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Abstract

There is provided a method, performed by a temporal filter. The method comprises obtaining a current picture and a set of one or more neighbor pictures comprising a first neighbor picture, wherein each of the one or more neighbor pictures either precedes or follows the current picture in a picture count order. The method comprises, based on a first block of pixel values of the current picture and a first block of pixel values in the first neighbor picture, determining a first filter weight, W1, for at least a first pixel value in the first block of pixel values of the current picture, wherein the first block of pixel values in the first neighbor picture correspond to the first block of pixel values in the current picture. The method comprises, calculating a first filtered pixel value, Pf1, at least using as inputs to the calculation: W1, P1, and Pr1, where PI is the first pixel value from the first block of pixel values of the current picture, and Pr1 is a pixel value from the first neighbor picture that corresponds to the first pixel value.

Claims20

Dependent claims

A method for producing filtered pixel values, the method comprising:

obtaining a current picture and a set of one or more neighbor pictures, wherein each of the one or more neighbor pictures either precedes the current picture or follows the current picture in a picture count order, the set of neighbor pictures comprising a first neighbor picture;
based on a first block of pixel values of the current picture and a first block of pixel values in the first neighbor picture, determining a first filter weight, W1, for at least a first pixel value in the first block of pixel values of the current picture, wherein the first block of pixel values in the first neighbor picture correspond to the first block of pixel values in the current picture;
calculating a first filtered pixel value, Pf1, at least using as inputs to the calculation:
W1, P1, and Pr1, where P1 is the first pixel value from the first block of pixel values of the current picture, and Pr1 is a pixel value from the first neighbor picture that corresponds to the first pixel value, wherein
determining W1 comprises determining a base weight, bw, and a sigma weight, sw, where W1 is a function of at least:
bw and sw, and
determining bw and sw comprises:
for each pixel value included in the first block of pixel values of the current picture, determining a squared difference by calculating:
(Pi−Pri){circumflex over ( )}2, where Pi is the pixel value included in the first block of pixels of the current picture, and Pri is a pixel value from the neighbor picture that corresponds to Pi;
summing the determined squared differences to produce a sum of squared differences, SSD, value;
calculating at least one of an error value, E, or a frequency metric, F, where E is a function of the SSD value and F is a function of the SSD value;
and
determining bw and sw based on E and/or F.

10 more elements

A temporal filter, the temporal filter comprising:

processing circuitry;
and
a memory, the memory containing instructions executable by the processing circuitry, wherein the temporal filter is operative to perform a method comprising:
obtaining a current picture and a set of one or more neighbor pictures, wherein each of the one or more neighbor pictures either precedes the current picture or follows the current picture in a picture count order, the set of neighbor pictures comprising a first neighbor picture;
based on a first block of pixel values of the current picture and a first block of pixel values in the first neighbor picture, determining a first filter weight, W1, for at least a first pixel value in the first block of pixel values of the current picture, wherein the first block of pixel values in the first neighbor picture correspond to the first block of pixel values in the current picture;
calculating a first filtered pixel value, Pf1, at least using as inputs to the calculation:
W1, P1, and Pr1, where P1 is the first pixel value from the first block of pixel values of the current picture, and Pr1 is a pixel value from the first neighbor picture that corresponds to the first pixel value, wherein
determining W1 comprises determining a base weight, bw, and a sigma weight, sw, where W1 is a function of at least:
bw and sw, and
determining bw and sw comprises:
for each pixel value included in the first block of pixel values of the current picture, determining a squared difference by calculating:
(Pi−Pri){circumflex over ( )}2, where Pi is the pixel value included in the first block of pixels of the current picture, and Pri is a pixel value from the neighbor picture that corresponds to Pi;
summing the determined squared differences to produce a sum of squared differences, SSD, value;
calculating at least one of an error value, E, or a frequency metric, F, where E is a function of the SSD value and F is a function of the SSD value;
and
determining bw and sw based on E and/or F.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/269,873Filed 10 Dec 2021 · us provisional application
Priority: 28 Dec 2020
Published: US 2024/0314307 A119 Sep 2024
Granted: 8 Jul 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04N 19/117
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: filters, e.g. for pre-processing or…
H04N 19/105
Selection of coding mode or of prediction mode: selection of the reference unit for prediction within a chosen coding or prediction mode, e.g.…
H04N 19/136
Characterised by the element, parameter or criterion affecting or controlling the adaptive coding: incoming video signal characteristics or properties
H04N 19/172
The unit being an image region, e.g. an object: the region being a picture, frame or field