Digital image processing for calculating a missing color value

• US 8,463,035 B2
• Filed: 05/27/2010
• Issued: 06/11/2013
• Est. Priority Date: 05/28/2009
• Status: Active Grant

• Current Assignee: HL Klemove Corporation
• Original Assignee: Gentex Corporation
• Inventors: Bechtel, Jon H., Andrus, Jeremy C., Sherman, Tom B.
• Primary Examiner(s): Chen, Wenpeng
• Application Number:
  US12/788,574
• Publication Number:
  US 20100303349A1
• Time in Patent Office: 1,111 Days
• Field of Search: 382/162, 382/167, 348/273
• US Class Current: 382/167
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/04 mounted inside vehicle B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: B60R 2011/0033 Rear-view mirrors
• CPC Class Codes: B60R 2300/105 using multiple cameras
• CPC Class Codes: B60R 2300/607 from a bird's eye viewpoint
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: H04N 2209/046 Colour interpolation to calculate the missing colour values
• 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

Abstract

A spectrally mosaiced digital image is provided with missing color data imputed for each pixel. Circuitry is provided that is configured to perform at least a portion of the calculations related to demosaicing a high dynamic range image.

Claims

1. An apparatus comprising:

a processing circuit for calculating a missing color value for a pixel location using an interpolation equation that is selected based on a direction of an edge feature in an image, wherein calculations performed using said interpolation equation are primarily based on values of eight spectrally mosaiced filtered pixels that are immediate neighbors of said pixel location and that include neighboring pixels with a spectral filter color that is different from said missing color value,

where said interpolation equation is N₂₂=(N₁₁+N₁₃+N₃₁+N₃₃)/4+(G₁₂−

G₂₁−

G₂₃+G₃₂)/2, wherein N₂₂ is a non-green missing color value for said pixel location;

N₁₁, N₁₃, N₃₁, and N₃₃ are color values of neighboring pixels with a non-green spectral filter color; and

G₁₂, G₂₁, G₂₃, and G₃₂ are color values of neighboring pixels with a green spectral filter color.

2. An image processing apparatus, comprising:

a processing circuit for calculating a first missing color value for a pixel location using an interpolation equation that is selected based on a direction of an edge feature in an image, wherein calculations performed using said interpolation equation are primarily based on values of eight spectrally mosaiced filtered pixels that are immediate neighbors of said pixel location and wherein said calculations include the values of neighboring pixels with a spectral filter color that is different from said first missing color value,

where said interpolation equation is selected from amongst at least one of the following equations;

N₂₂=(N₁₁+N₁₃+N₃₁+N₃₃)/4+(G₁₂−

G₂₁−

G₂₃+G₃₂)/2;

N₂₂=(N₁₁+N₁₃+N₃₁+N₃₃)/4+(−

G₁₂+G₂₁+G₂₃−

G₃₂)/2;

N₂₂=(N₂₁+N₂₃)/2+(−

G₁₁−

G₁₃−

G₃₁−

G₃₃+4G₂₂)/4;

N₂₂=N₂₃+(−

G₁₃−

G₃₃+2G₂₂)/4;

N₂₂=N₂₁+(−

G₁₁−

G₃₁+2G₂₂)/4;

N₂₂=(N₁₂+N₃₂)/2+(−

G₁₁−

G₁₃−

G₃₁−

G₃₃+4G₂₂)/4;

N₂₂=N₃₂+(−

G₃₁−

G₃₃+2G₂₂)/4; and

N₂₂=N₂₁+(−

G₁₁−

G₁₃+2G₂₂)/4,

Wherein;

N₂₂ is a non-green missing color value for said pixel location;

N₁₁, N₁₃, N₃₁, and N₃₃ are color values of neighboring pixels with a non-green spectral filter color that is the same color as the first missing color;

G₁₂, G₂₁, G₂₃, and G₃₂ are color values of neighboring pixels with a green spectral filter color;

N₂₁ and N₂₃ are interpolated color values of neighboring pixels with a non-green spectral filter color that is a different color from the first missing color; and

G₁₁, G₁₃, G₃₁, and G₃₃ are interpolated green color values of neighboring pixels with a non-green spectral filter color that is the same color as the first missing color, and G₂₂ is the green color value of the pixel location.

3. An apparatus as in claim 2, wherein said pixel location has a green color filter.

4. An apparatus as in claim 2, wherein said pixel location has a red color filter.

5. An apparatus as in claim 2, wherein said pixel location has a blue color filter.