# US 2010/0165157 A1 · Apparatus for demosaicing colors and method thereof

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- Number: US 2010/0165157 A1
- Document ID: US20100165157A1
- Status: Published application
- Kind: A1
- Application number: 12/648,929
- Filed: 2009-12-29
- Published: 2010-07-01
- Earliest claimed: 2008-12-30
- Assignees: Dongbu HiTek Co., Ltd.
- Inventors: Ji Cheol Hyun; Seung Heon Jeon
- Web page: https://patentgrep.com/patent/US20100165157A1

## CPC

- H04N 23/843: {Demosaicing, e.g. interpolating colour pixel values}
- H04N 25/134: {based on three different wavelength filter elements}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An apparatus and method for demosaicing colors in an image sensor can accurately locate edge directionality by detecting a successive 1-line edge precisely. The embodiments may include an image sensor containing information on a color signal detected from each pixel, a first line memory receiving and storing output data from the image sensor, a missing green information extractor extracting missing green pixel information from the data of the first line memory, a delayer receiving the data of the first line memory, the delayer delaying the received data for a prescribed duration, the delayer outputting the delayed data, a second line memory temporarily storing the data outputted from the missing green information extractor and the data provided via the delayer, and a missing red/blue information outputter extracting missing red/blue information from the data of the second line memory.

## Claims

### Claim 1

An apparatus comprising:
an image sensor containing information on a color signal detected from each pixel;
a first line memory receiving and storing output data from the image sensor;
a missing green information extractor extracting missing green pixel information from the data of the first line memory;
a delayer receiving the data of the first line memory, the delayer delaying the received data for a prescribed duration, the delayer outputting the delayed data;
a second line memory temporarily storing the data outputted from the missing green information extractor and the data provided via the delayer; and
a missing red/blue information outputter extracting missing red/blue information from the data of the second line memory.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the missing green information extractor includes a gradient calculating unit for finding a gradient in a current pixel.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the missing green information extractor includes a line edge determining unit comparing a minimum/maximum difference value of green pixel values within a kernel to a threshold.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the line edge determining unit is configured to determine one of a presence and a non-presence of a successive 1-line edge region according to a result of the comparison.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the missing green information extractor includes a directionality determining unit determining directionality of an edge in a current center pixel through edge sensing for 8 neighbor pixels centering on a center pixel.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the missing green information extractor includes an edge classifying unit configured to discriminate one value selected from the group consisting of a plain plane, a successive 1-line edge region, a vertical edge region, a horizontal edge region and a texture edge region.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the edge classifying unit is configured to discriminate the one value based on values provided by the gradient calculating unit and the line edge determining unit.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the missing green information extractor includes an edge refining unit configured to modify a neighbor edge direction.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the edge refining unit is configured to modify the neighbor edge direction using values provided by the edge classifying unit and the directionality determining unit, and using a threshold.

### Claim 10 (depends on 9)

The apparatus of claim 9, wherein the gradient calculating unit uses color demosaicing using variance of color correlation.

### Claim 11 (depends on 10)

The apparatus of claim 10, wherein the gradient calculating unit applies equations, which define a color difference between neighbor pixels, to color demosaicing using variance of color correlation, including:
dH=|Ki,jH−Ki,j−2H|+|Ki,jH−Ki,j+2H|
and
dV=|Ki,jV−Ki−2,jV|+|Ki,jV−Ki+2,jV|,
wherein the indication ‘Kij’ is used to indicate a color subpixel value, i indicates a row of a subpixel value, j indicates a column off the subpixel value, dH indicates a horizontal gradient, dV indicates a vertical gradient.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein horizontal and vertical weights are set to
KUH=[(imgi,j−1+imgi,j+1)>>]+[(imgi,j−2+2*imgi,j+imgi,j+2)>>2]
and
KUV=[(imgi−1,j+imgi+1,j)>>]+[(imgi−2,j+2*imgi,j+imgi+2,j)>>2],
respectively.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the missing green information extractor extracts the missing green pixel information from the data of the first line memory by supplementing a fault of the incorrect edge sensing in a region where a successive 1-line narrow edge exists.

### Claim 14

A method comprising:
a first color information storing step of receiving and storing information on a color signal detected in each cell from an image sensor;
a missing green information extracting step of extracting missing green pixel information in the first color information storing step;
a delaying step of delaying the first color information data for a prescribed duration and then outputting the delayed data;
a second color information storing step of storing data extracted through the missing green information extracting step and data provided via the delaying step; and
a missing red/blue information outputting step of extracting missing red/blue information from the data stored in the second color information storing step.

### Claim 15 (depends on 14)

The method of claim 14, wherein the missing green information extracting step includes finding a gradient in a current pixel.

### Claim 16 (depends on 15)

The method of claim 15, wherein the missing green information extracting step includes comparing a minimum/maximum difference value of green pixel values within a kernel to a threshold and then determining a presence or non-presence of a successive 1-line edge region according to a result of the comparison.

### Claim 17 (depends on 16)

The method of claim 16, wherein the missing green information extracting step includes determining directionality of an edge in the current center pixel through edge sensing for 8 neighbor pixels centering on a center pixel.

### Claim 18 (depends on 17)

The method of claim 17, wherein the missing green information extracting step includes an edge classifying step of discriminating one value selected from the group consisting of a plain plane, a successive 1-line edge region, a vertical edge region, a horizontal edge region and a texture edge region based on the gradient value and a presence or non-presence of a 1-line edge region.

### Claim 19 (depends on 18)

The method of claim 18, wherein the missing green information extracting step includes an edge refining step of modifying a neighbor edge direction using a threshold based on the classified edge and directionality of the edge.

### Claim 20 (depends on 14)

The method of claim 14, the missing green information extracting step comprising the step of extracting the missing green pixel information by supplementing a fault of the incorrect edge sensing in a region where a successive 1-line narrow edge exists in the first color information storing step.