# US 2010/0166333 A1 · Noise filter

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- Number: US 2010/0166333 A1
- Document ID: US20100166333A1
- Status: Published application
- Kind: A1
- Application number: 12/643,615
- Filed: 2009-12-21
- Published: 2010-07-01
- Earliest claimed: 2008-12-29
- Assignees: Dongbu HiTek Co., Ltd.
- Inventors: MIN GYU SHIN
- Web page: https://patentgrep.com/patent/US20100166333A1

## CPC

- G06T 5/70: Denoising; Smoothing
- G06V 10/30: Noise filtering
- G06T 2207/20192: Edge enhancement; Edge preservation
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

A noise filter according to an embodiment includes: a first filter that functions as an edge detector to detect a high-frequency component area of an image; a second filter that performs a noise filtering function for the remaining areas of the image while conserving the high-frequency component area detected by the first filter; and a function processor that controls operations of the first filter and the second filter. According to an embodiment, since noise filtering for only a noise component area is performed by dividing the image into a high-frequency component area and a noise component area, it is possible to minimize deterioration of the high-frequency area and improve the resolution and quality of the image.

## Claims

### Claim 1

A noise filter, comprising:
a first filter performing as an edge detector to detect a high-frequency component area of an image;
a second filter performing a noise filtering function for remaining areas of the image while conserving the high-frequency component area detected by the first filter; and
a function processor that controls operations of the first filter and the second filter.

### Claim 2 (depends on 1)

The noise filter according to claim 1, wherein the first filter is expressed by a matrix function of
FC
1
=
[
1.0000
1.4142
1.0000
0.0000
0.0000
0.0000
-
1.0000
-
1.4142
-
1.0000
]
FC
2
=
[
1.0000
0.0000
-
1.0000
1.4142
0.0000
-
1.4142
1.0000
0.0000
-
1.0000
]
FC
3
=
[
0.0000
-
1.0000
1.4142
1.0000
0.0000
-
1.0000
-
1.4142
1.0000
0.0000
]
FC
4
=
[
1.4142
-
1.0000
0.0000
-
1.0000
0.0000
1.0000
0.0000
1.0000
-
1.4142
]

### Claim 3 (depends on 1)

The noise filter according to claim 1, wherein the first filter performs as the edge detector in eight directions from a pixel of the image and uses a 3×3 kernel in each direction.

### Claim 4 (depends on 1)

The noise filter according to claim 1, wherein the second filter is a bilateral filter (BF) and performs the noise filtering function while conserving a second high-frequency component area comparatively smaller than the high-frequency component area detected by the first filter by performing filtering by using two attributes.

### Claim 5 (depends on 4)

The noise filter according to claim 4, wherein the two attributes are “spatial Gaussian” and “range Gaussian”.

### Claim 6 (depends on 1)

The noise filter according to claim 1, wherein the second filter is defined by an equation of
BF

[
I
]
p
=

1
W
p

∑
q
∈
S

G
σ
s

(

p
-
q

)

G
σ
r

(
I
p
-
I
q
)

I
q
≈

∑
q
∈
S

G
S

G
σ
r

(
I
p
-
I
q
)

I
q
∑
q
∈
S

G
S

G
σ
r

(
I
p
-
I
q
)
=

∑
q
∈
S


-
(
I
q
-
I
p
)
2
2

σ
r
2

G
S

I
q
∑
q
∈
S


-
(
I
q
-
I
p
)
2
2

σ
r
2

G
S
,
where Gσs (∥p−q∥)≈Gs represents a matrix function of
(
1
/
16
)
×
[
6
8
9
10
9
8
6
8
10
12
13
12
10
8
9
12
14
15
14
12
9
10
13
15
16
15
13
10
9
12
14
15
14
12
9
8
10
12
13
12
10
8
6
8
9
10
9
8
6
]
.

### Claim 7 (depends on 1)

The noise filter according to claim 1, wherein the function processor sequentially actuates the first filter and then the second filter for each pixel.

### Claim 8 (depends on 1)

The noise filter according to claim 1, wherein the function processor judges whether noise filtering is not required with a predetermined area in accordance with the position of each pixel and the intensity of a high-frequency component after the first filter is actuated, and selectively actuates the second filter depending on the judgment result.