Scaling algorithm for efficient color representation/recovery in video

• US 6,236,433 B1
• Filed: 09/29/1998
• Issued: 05/22/2001
• Est. Priority Date: 09/29/1998
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Metz, Werner, Acharya, Tinku
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Tran, Trang U.
• Application Number:
  US09/163,022
• Time in Patent Office: 966 Days
• Field of Search: 348/561, 348/562, 348/576, 348/581, 348/582, 348/273, 348/272, 348/231, 348/391, 348/392, 345/127, 345/129, 345/130, 345/150, 345/152, 358/512, 358/525, 358/518, 358/517, 358/513-515, 382/162, 382/166, 382/298, 382/299, 382/167
• US Class Current: 348/273
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
• CPC Class Codes: G06T 3/403 Edge-driven scaling; Edge-based scaling
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 7/01 Conversion of standards , e.g. involving analogue television standards or digital television standards processed at pixel level

Abstract

What is disclosed is a method comprising defining a scaling region by indicating in a CFA (Color Filter Array) a starting location, and generating a super-pixel which is a downscaled version of the scaling region, the super-pixel fully color interpolated, the downscaling and the color interpolation achieved in an integrated manner.

Claims

1. A method comprising:

defining a scaling region in a CFA (Color Filter Array) image; and

generating a super-pixel which is a downscaled version of said scaling region, said super-pixel being fully color interpolated, by applying a mask to a sub-image region of the CFA image, said sub-image region having pixels of all the same color plane and normalizing the result of applying said mask to form a color component of said super-pixel, said color component having the color associated with the sub-image region.

2. A method according to claim 1 wherein said CFA has each pixel associated with only one of three color planes.

3. A method according to claim 2 wherein said color planes are Red, Green and Blue.

4. A method according to claim 2 wherein said CFA is arranged in a Bayer pattern.

5. A method according to claim 1 wherein said down scaling is 4 to 1 down scaling.

6. A method according to claim 3 wherein full color interpolation for each super-pixel denotes that each super-pixel has components for all three said Red, Green and Blue color planes.

7. A method according to claim 1 wherein said mask is configured to favor a central portion of said sub-image region while maintaining the ability to represent edge features occurring elsewhere than said central portion.

8. A method according to claim 2 wherein said color planes are Magenta, White and Yellow.

9. An apparatus comprising:

a scaling and color interpolation unit configured to transform CFA (Color Filter Array) pixels, each associated with only one of multiple color components, into downscaled super-pixels, each super-pixel having all of said color components, by applying a mask to a sub-image region of the CFA pixels, said sub-image region having pixels of all the same color plane and normalizing the result of applying said mask to form a color component of a super-pixel, said color component having the color associated with the sub-image region.

10. An apparatus according to claim 9 comprising:

a memory coupled to said scaling and color interpolation unit, configured to store said super-pixel data.

11. An apparatus according to claim 9 comprising:

an image sensor coupled to said scaling and color interpolation unit, said sensor providing in a Bayer pattern data for said CFA.

12. An apparatus according to claim 9 wherein said scaling and color interpolation unit is incorporated into an imaging device.

13. An apparatus according to claim 12 wherein said imaging device is a digital camera.

14. An article of manufacture comprising a computer readable medium having instructions stored thereon which when executed by a processor cause:

a scaling region to be defined in a CFA (Color Filter Array) image; and

a super-pixel which is a downscaled version of said scaling region to be generated, said super-pixel being fully color interpolated, by applying a mask to a sub-image region of the CFA image, said sub-image region having pixels of all the same color plane and normalizing the result of applying said mask to form a color component of said super-pixel, said color component having the color associated with the sub-image region.

15. The article of manufacture of claim 14 wherein said CFA image has each pixel therein associated with only one of three color planes.

16. The article of manufacture of claim 15 wherein said color planes are Red, Green and Blue.

17. The article of manufacture of claim 16 wherein said CFA image is arranged in a Bayer pattern.

18. The article of manufacture of claim 17 wherein full color interpolation for each super-pixel denotes that each super-pixel has components for all three of said Red, Green, and Blue color planes.

19. The article of manufacture of claim 14 wherein the medium includes further instructions which when executed by the processor cause said mask to be configured to favor a central portion of said sub-image region while maintaining the ability to represent edge features occurring elsewhere than said central portion.