Apparatus for demosaicing colors and method thereof

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,

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.

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

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

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

9. 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.

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

11. 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=|K i,j H −K i,j−2 H |+|K i,j H −K i,j+2 H |

and

dV=|K i,j V −K i−2,j V |+|K i,j V −K i+2,j V |

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.

12. The apparatus of claim 11 , wherein horizontal and vertical weights are set to

K U H =[( img i,j−1 +img i,j+1 )>>1]+[( img i,j−2 +2 *img i,j +img i,j+2 )>>2]

and

K U V =[( img i−1,j +img i+1,j )>>1]+[( img i−2,j +2 *img i,j +img i+2,j )>>2],

respectively.

13. 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 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;

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.

14. The method of claim 13 , wherein the missing green information extracting step includes finding a gradient in a current pixel.

15. The method of claim 14 , 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.

16. The method of claim 15 , 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.

17. The method of claim 16 , 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.

18. The method of claim 17 , 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.