Method for removing noise of image signal and image processing device using the same

Patent metadata

Field	Value
Publication number	US-2015131922-A1
Application number	US-201414303129-A
Country	US
Kind code	A1
Filing date	Jun 12, 2014
Priority date	Nov 11, 2013
Publication date	May 14, 2015
Grant date	—

Abstract

A method of removing noise of an image signal includes receiving a first frame and a second frame, generating a spatial filtering frame by performing spatial filtering on the second frame, generating a temporal filtering frame by performing temporal filtering on the first frame, and generating a second filtering frame, using the temporal filtering frame, the spatial filtering frame, and the second frame.

First claim

1 - 6 . (canceled)

7 . An image processing device configured to process an image signal, the image signal including at least a first frame and a second frame, the image processing device comprising:
a frame rate conversion (FRC) unit configured to generate an intermediate frame in a sequence between a first filtering frame and a second filtering frame; and a noise filter unit configured to generate the second filtering frame by removing noise in the second frame, using both of temporal filtering and spatial filtering.

8 . The device of claim 7 , wherein the first filtering frame and the second filtering frame are generated, using the first frame and the second frame, respectively, and
the first frame is a n th frame in a sequence and the second frame is a n+1 th frame in the sequence, wherein n is a natural number.

9 . The device of claim 7 , wherein the noise filter unit comprises:
a spatial filter unit configured to spatially filter the second frame to generate a spatial filtering frame; a temporal filter unit configured to temporally filter the first frame to generate a temporal filtering frame; and a spatial-temporal filter unit configured to generate the second filtering frame from the spatial filtering frame and the temporal filtering frame.

10 . The device of claim 9 , wherein the noise filter unit further comprises:
a weight unit configured to obtain a temporal weight by measuring a similarity between the first frame and the second frame, and wherein
the temporal filter unit is configured to temporally filter the first frame based on the temporal weight.

11 . The device of claim 10 , wherein the temporal weight includes a global weight associated with a global motion vector (GMV) between the first and second frames, and a local weight associated with a local motion vector (LMV) between the first and second frames, and
the temporal filter unit is configured to temporally filter the first frame further based on the GMV weight and the LMV weight.

12 . The device of claim 11 , wherein the spatial-temporal filter unit generates the second filtering frame based on:
F′ 2 ( i, j )=( F temporal ( i, j )+(1−min(αglobal, αlocal))· F spatial ( i, j )+αuser· F 2 ( i, j ))/αtotal
where F′ 2 is the second filtering frame, F temporal is the temporal filtering frame satisfying F temporal (i, j)=αglobal·F 1 (i-gmvy, j-gmvx)+αlocal·F 1 (i-lmvy, j-lmvx), F 1 is the first frame, F 2 is the second frame, F spatial is the spatial filtering frame, αglobal is the GMV weight, αlocal is the LMV weight, αuser is a desired weight, and αtotal is the sum of the αglobal, the αlocal, (1−min (αglobal, αlocal)), and αuser, and min (αglobal, αlocal) is a minimum value of the global and the αlocal.)

13 . The device of claim 9 , wherein the noise filter unit further comprises:
an interpolator configured to convert a first filtering frame into the first frame, and provide the first frame to the weight unit, the first filtering frame being a previously filtered frame with noise therein removed.

14 . The device of claim 13 , wherein the FRC unit is configured to generate the intermediate frame based on the first filtering frame and the second filtering frame.

15 . An image display device comprising:
the image processing device of claim 7 ; and a display unit configured to,
perform signal processing on one or more of the first filtering frame, the second filtering frame and the intermediate frame, and
display one or more of the first filtering frame, the second filtering frame and the intermediate frame on a screen.

16 . An image processing device comprising:
a buffer configured to store a filtered first frame and an unfiltered second frame; a noise filter configured to temporally and spatially filter the unfiltered second frame to generate a filtered second frame; and a frame rate converter configured to generate an intermediate frame in a sequence between the filtered first frame and the filtered second frame.

17 . The image processing device of claim 16 , wherein the sequence of the filtered first frame and the filtered second frame are part of a picture sequence, and the frame converter is configured to vary a frame rate of the picture sequence by inserting the intermediate frame therein such that one or more of a motion blur and a judder in the picture sequence is reduced.

18 . The image processing device of claim 16 , wherein the noise filter is configured to temporally filter the unfiltered second frame based on a global motion estimate without partitioning the unfiltered second frame.

19 . The image processing device of claim 16 , wherein the noise filter comprises:
a spatial filter configured to spatially filter the unfiltered second frame to generate a spatial filtered frame; a temporal filter configured to temporally filter an unfiltered first frame to generate a temporal filtered frame, the unfiltered first frame being an unfiltered version of the filtered first frame; and a spatial-temporal filter configured to generate the filtered second frame based on the spatial filtered frame and the temporal filtered frame.

20 . The image processing device of claim 19 , wherein the spatial-temporal filter is configured to provide the filtered second frame to the buffer as a next filtered first frame, and the noise filter is configured to recursively perform the temporally and spatially filtering thereon.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Simson Yonatan Shlomo

Classifications

• G06T5/50 Primary

  using two or more images, e.g. averaging or subtraction · CPC title

• G06T5/10 Primary

  using non-spatial domain filtering · CPC title

• G06T2207/10016

  Video; Image sequence · CPC title

• G06T2207/20182

  Noise reduction or smoothing in the temporal domain; Spatio-temporal filtering · CPC title

• H04N5/21

  Circuitry for suppressing or minimising disturbance, e.g. moiré or halo · CPC title