# US 7,609,912 B2 · Image transforming device and method based on edges

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- Number: US 7,609,912 B2
- Document ID: US7609912B2
- Status: Granted
- Kind: B2
- Application number: 11/090,566
- Filed: 2005-03-28
- Published: 2005-10-20
- Granted: 2009-10-27
- Earliest claimed: 2004-04-20
- Assignees: Samsung Electronics Co., Ltd.
- Inventors: Won-Seok Chae
- Web page: https://patentgrep.com/patent/US7609912B2

## CPC

- G06T 3/403: Edge-driven scaling; Edge-based scaling
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

An image transforming apparatus and method include a linear interpolation block for generating linear interpolation information for a pixel to be interpolated between original pixels of a predetermined image; an edge information generating block for generating edge information and edge location information; a weight determining block for determining a weight for the linear interpolation information and the edge information of the interpolation pixel based on the edge location information; an interpolation information generating block for determining a pixel value of the interpolation pixel by reflecting the weight to the edge information and the linear interpolation information; and an interpolating block for generating the interpolation pixel based on the pixel value determined in the interpolation information generating block. Therefore, an image can be transformed into a high-resolution enlarged image with an edge area expressed clearly.

## Claims

### Claim 1

An apparatus for transforming an image, comprising:
a linear interpolation block for generating linear interpolation information for an interpolation pixel to be interpolated between original pixels of a predetermined image;
an edge information generating block for generating edge information which represents a pixel value of a pixel for indicating an edge and generating edge location information for indicating a location of an edge area of the image using two threshold values, within each of blocks consisting of the original pixel and interpolation pixel, respectively;
a weight determining block for determining a weight for the linear interpolation information and the edge information of the interpolation pixel based on the edge location information;
an interpolation information generating block for determining a pixel value of the interpolation pixel by reflecting the weight to the edge information and the linear interpolation information; and
an interpolating block for generating the interpolation pixel based on the pixel value determined in the interpolation information generating block.

### Claim 2 (depends on 1)

The apparatus as recited in claim 1, further comprising an edge determining block for determining whether a predetermined block is an edge block that includes the edge surface, when the image is divided into a plurality of blocks, each comprising the original pixels and a predetermined number of interpolation pixels,
wherein, if the block is not determined to be the edge block, the interpolating block generates the interpolation pixels based on the linear interpolation information.

### Claim 3 (depends on 1)

The apparatus as recited in claim 1, wherein the edge information generating block comprises:
a threshold value determining unit for determining a predetermined upper threshold value and a predetermined lower threshold value;
a primary edge information generating unit for comparing the linear interpolation information with the upper threshold value and the lower threshold value, and generating primary edge information for indicating pixel values of the pixels in the block and primary edge location information for indicating a location of a pixel that forms the edge surface; and
a filtering unit for converting the primary edge information into the edge information by performing median filtering and transforming the primary edge location information into the edge location information based on the transformed edge information.

### Claim 4 (depends on 3)

The apparatus as recited in claim 3, wherein the threshold value determining unit calculates the upper threshold value and the lower threshold value based on an equation, which is expressed as:
Th
⁢
⁢
1
=
Max
+
Min
2
+
α
,
Th
⁢
⁢
2
=
Max
+
Min
2
-
α
,
wherein Th1 denotes the upper threshold value, Th2 denotes the lower threshold value, Max and Min denote the maximum pixel value and the minimum pixel value among pixel values of adjacent pixels of an original pixel, respectively, and αdenotes an arbitrary constant.

### Claim 5 (depends on 3)

The apparatus as recited in claim 3, wherein the primary edge information generating unit generates the primary edge information and the primary edge location information based on an equation which is expressed as:
When LI>Th1: Et=Max, Lt=0
When LI<Th2: Et=Min, Lt=0
When Th2<LI<Th1:
Et
=
(
Max
-
Min
)
×
(
LI
-
Th
⁢
⁢
1
)
(
Th
⁢
⁢
1
-
Th
⁢
⁢
2
)
+
Min
,
Lt
=
1
,
wherein LI denotes linear interpolation information, Et denotes primary edge information, Lt denotes primary edge location information, Th1 denotes an upper threshold value, Th2 denotes a lower threshold value, and Max and Min denote the maximum pixel value and the minimum pixel value among pixel values of adjacent pixels of an original pixel, respectively.

### Claim 6 (depends on 5)

The apparatus as recited in claim 5, wherein the filtering unit determines a predetermined size of a window with a predetermined pixel of the block at the center, arranges primary edge information of each pixel of the window sequentially, and determines a median thereof as the edge information of the pixel.

### Claim 7 (depends on 1)

The apparatus as recited in claim 1, wherein the weight determining block determines a weight for edge information of each pixel in the block based on an equation which is expressed as:
w
=
d
⁢
⁢
1
d
⁢
⁢
1
+
d
⁢
⁢
2
,
wherein w denotes a weight, and d1 denotes a distance to a non-edge block among adjacent blocks, and d2 denotes a distance to an edge area in the block.

### Claim 8 (depends on 1)

The apparatus as recited in claim 1, wherein the interpolation information generating block comprises:
a first multiplier for multiplying the edge information by a first weight;
a second multiplier for multiplying the linear interpolation information by a second weight; and
an adder for adding operation results of the first multiplier and the second multiplier.

### Claim 9

An image transforming method of an apparatus for transforming an image, comprising the steps of:
a) generating linear interpolation information for an interpolation pixel to be interpolated between original pixels of a predetermined image;
b) generating edge information which signifies a pixel value of a pixel for indicating an edge of the image and generating edge location information for indicating a location of an edge area of the image using two threshold values, within each of blocks consisting of the original pixel and interpolation pixel, respectively;
c) determining a weight for the linear interpolation information and the edge information of the interpolation pixel based on the edge location information;
d) determining a pixel value of the interpolation pixel by reflecting the weight to the edge information and the linear interpolation information; and
e) generating the interpolation pixel based on the determined pixel value,
wherein the steps are preformed by the apparatus.

### Claim 10 (depends on 9)

The method as recited in claim 9, further comprising:
f) determining whether a predetermined block is an edge block that comprises the edge surface, when the image is divided into a plurality of blocks, each comprising the original pixels and a predetermined number of interpolation pixels,
g) generating the interpolation pixels based on the linear interpolation information if the block is not determined to be the edge block.

### Claim 11 (depends on 10)

The method as recited in claim 10, wherein the step b) comprises the sub-steps of:
b1) determining a predetermined upper threshold value and a predetermined lower threshold value;
b2) comparing the linear interpolation information with the upper threshold value and the lower threshold value;
b3) generating primary edge information for expressing pixel values of the pixels in the block and primary edge location information for expressing a location of a pixel that forms the edge surface;
b4) converting the primary edge information into the edge information by performing median filtering; and
b5) converting the primary edge location information into the edge location information based on the converted edge information.

### Claim 12 (depends on 11)

The method as recited in claim 11, wherein, in the step b1), the upper threshold value and the lower threshold value are calculated based on an equation, which is expressed as:
Th
⁢
⁢
1
=
Max
+
Min
2
+
α
,
Th
⁢
⁢
2
=
Max
+
Min
2
-
α
,
wherein Th1 denotes the upper threshold value, Th2 denotes the lower threshold value, Max and Min denote the maximum pixel value and the minimum pixel value, respectively, among pixel values of adjacent pixels of an original pixel, respectively; and α denotes an arbitrary constant.

### Claim 13 (depends on 11)

The method as recited in claim 11, wherein, in the step b3), the primary edge information and the primary edge location information are generated based on an equation which is expressed as:
When LI>Th1: Et=Max, Lt=0
When LI<Th2: Et=Min, Lt=0
When Th2<LI<Th1:
Et
=
(
Max
-
Min
)
×
(
LI
-
Th
⁢
⁢
1
)
(
Th
⁢
⁢
1
-
Th
⁢
⁢
2
)
+
Min
,
Lt
=
1
,
wherein LI denotes linear interpolation information, Et denotes primary edge information, Lt denotes primary edge location information, Th1 denotes an upper threshold value, Th2 denotes a lower threshold value, and Max and Min denote the maximum pixel value and the minimum pixel value among pixel values of adjacent pixels of an original pixel, respectively.

### Claim 14 (depends on 11)

The method as recited in claim 11, wherein the step b4) comprises the sub-steps of:
b4-1) determining a predetermined size of a window with a predetermined pixel of the block at the center; and
b4-2) arranging primary edge information of each pixel of the window sequentially, and determining a median thereof as the edge information of the pixel.

### Claim 15 (depends on 9)

The method as recited in claim 9, wherein, in the step c), a weight for edge information of each pixel in the block is determined based on an equation which is expressed as:
w
=
d
⁢
⁢
1
d
⁢
⁢
1
+
d
⁢
⁢
2
,
wherein w denotes a weight, and d1 denotes a distance to a non-edge block among adjacent blocks, and d2 denotes a distance to an edge area in the block.

### Claim 16 (depends on 9)

The method as recited in claim 9, wherein the step d) comprises the sub-steps of:
d1) multiplying the edge information by a first weight;
d2) multiplying the linear interpolation information by a second weight; and
d3) adding operation results of the step d1) and the step d2).