Enhancing sharpness in video images

• US 20060279660A1
• Filed: 06/10/2005
• Published: 12/14/2006
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Ali, Walid
• Granted Patent: US 7,847,863 B2
• Time in Patent Office: Days
• US Class Current: 348/625
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement
• CPC Class Codes: H04N 5/208 for compensating for attenuation of high frequency components, e.g. crispening, aperture distortion correction

Abstract

A method of selectively sharpening video data may include, for at least some pixels in the video data, generating a sharpened value for a pixel value in an image. The sharpened value may be disregarded if a combination of the pixel value and the sharpened value is in a coring region. The sharpened value also may be disregarded if a combination of the pixel value and the sharpened value is a clipping region. The combination of the pixel value and the sharpened value may be output if the combination is not in the coring region or in the clipping region.

Claims

1. A method, comprising:

generating a sharpened value for a pixel value in an image;

disregarding the sharpened value if a combination of the pixel value and the sharpened value is in a coring region or in a clipping region; and

outputting the combination of the pixel value and the sharpened value if the combination is not in the coring region or in the clipping region.

2. The method of claim 1, wherein the generating includes:

convolving the pixel value and a number of surrounding pixels with a kernel to produce a sharpened pixel array.

3. The method of claim 2, wherein the generating further includes:

amplifying a value in the sharpened pixel array to produce the sharpened value.

4. The method of claim 1, wherein the disregarding includes:

outputting a zero value if the combination of the pixel value and the sharpened value is in the coring region.

5. The method of claim 1, wherein the disregarding includes:

outputting a ceiling value if the combination of the pixel value and the sharpened value is in the clipping region.

6. The method of claim 1, wherein the disregarding includes:

outputting the pixel value if a number of pixels surrounding the pixel value are sufficiently smooth.

7. A method, comprising:

generating an enhancement value for use in producing an output pixel value from an input pixel value in an image;

outputting a zero value as the output pixel value if a combination of the enhancement value and the input pixel value falls below a coring threshold; and

outputting the input pixel value as the output pixel value if a measure based on the input pixel and a number of surrounding pixels falls indicates smoothness.

8. The method of claim 7, further comprising:

outputting the combination of the enhancement value and the input pixel as the output pixel value if the combination of the enhancement value and the input pixel value falls above the coring threshold and if the measure based on the input pixel and a number of surrounding pixels falls does not indicate smoothness.

9. The method of claim 7, further comprising:

. outputting a ceiling value as the output pixel value if a combination of the enhancement value and the input pixel value falls above a clipping threshold.

10. The method of claim 9, further comprising:

outputting the combination of the enhancement value and the input pixel as the output pixel value if the combination of the enhancement value and the input pixel value falls above the coring threshold and below the clipping threshold and if the measure based on the input pixel and a number of surrounding pixels falls does not indicate smoothness.

11. The method of claim 7, wherein the generating includes:

convolving the input pixel value and a number of surrounding pixels with a kernel array.

12. A system, comprising:

a sharpening portion to sharpen a pixel of video data and output a sharpened pixel value;

a combiner to selectively combine the sharpened pixel value and the pixel of video data and to output an enhanced pixel value; and

a module portion coupled between the sharpening portion and the combiner to prevent coring or clipping in the enhanced pixel value output by the combiner.

13. The system of claim 12, wherein the sharpening portion includes:

a convolver to convolve the pixel and a number of surrounding pixels with a similarly sized kernel.

14. The system of claim 13, wherein the sharpening portion further includes:

an amplifier to amplify an output of the convolver to generate the sharpened pixel value.

15. The system of claim 12, wherein the module portion includes:

a coring prevention module to cause enhanced pixel values that would be less than a coring threshold to be zero.

16. The system of claim 12, wherein the module portion includes:

a clipping prevention module to limit enhanced pixel values that would be greater than a clipping threshold to a value of the clipping threshold.

17. The system of claim 12, wherein the module portion includes:

a local sharpness controller to cause the enhanced pixel value to be the same as the pixel of video data when an area of pixels around the pixel of video data is substantially smooth.

18. The system of claim 12, further comprising:

a deinterlacing module, a noise reduction module, or a scaling module operatively coupled to an output of the combiner to further condition the enhanced pixel value.

19. The system of claim 12, further comprising:

a display buffer operatively coupled to an output of the combiner to buffer enhanced pixel values before display.

20. A method, comprising:

generating an enhancement value for use in producing an output pixel value from an input pixel value in an image;

outputting a ceiling value as the output pixel value if a combination of the enhancement value and the input pixel value falls above a clipping threshold.

outputting the input pixel value as the output pixel value if a measure based on the input pixel and a number of surrounding pixels falls indicates smoothness.

21. The method of claim 20, further comprising:

outputting the combination of the enhancement value and the input pixel as the output pixel value if the combination of the enhancement value and the input pixel value falls below the clipping threshold and if the measure based on the input pixel and a number of surrounding pixels falls does not indicate smoothness.

22. The method of claim 20, wherein the generating includes:

convolving the input pixel value and a number of surrounding pixels with a kernel array.