Image blurring
View Patent ↗A method of blurring an image includes acquiring two images of nominally a same scene taken at a different light exposure levels. At least one region of one of the images includes pixels having saturated intensity values. For at least one of the saturated pixels, values are extrapolated from the other image. At least a portion of a third image is blurred and re-scaled including pixels having the extrapolated values.
1. A digital image processing device operable to blur an acquired image, comprising a controller and one or more processor readable storage devices having processor readable code embodied thereon, said processor readable code for programming one or more processors to perform a method of creating blur in a digital image, the method comprising:
(a) acquiring a first image of a scene taken at a first exposure level;
(b) acquiring a second image of nominally the same scene taken at a second exposure level greater than said first exposure level, wherein at least one region of said second image includes one or more pixels having saturated intensity values, and wherein one or more corresponding pixels of the first image do not have saturated intensity values;
(c) for at least one of said saturated pixels, extrapolating one or more values from said first image;
(d) generating a third image comprising pixels of said second image having non-saturated values, and pixels having said one or more extrapolated values;
(e) blurring at least a portion of the third image; and
(f) re-scaling the blurred portion of the third image.
2. The digital image processing device of claim 1 , wherein the first image is acquired without a flash and wherein the second image is acquired with a flash exposure level.
3. The digital image processing device of claim 1 , wherein extrapolating a value for a saturated pixel comprises:
calculating at least one ratio of an intensity of a pixel in said first image to an intensity of at least one non-saturated pixel; and
providing said extrapolated value for a selected pixel in accordance with said intensity ratio.
4. The digital image processing device of claim 3 , wherein said non-saturated pixel comprises a pixel in said first image which corresponds to a pixel in said second image which has not undergone saturation clipping.
5. The digital image processing device of claim 1 , wherein the method further comprises:
determining one or more portions of said third image which correspond to foreground of the image and portions which correspond to background of the image; and
blurring said background portions.
6. The digital image processing device of claim 1 , wherein said blurring of said third image comprises applying at least one convolution kernel to said at least one portion.
7. The digital image processing device of claim 6 , wherein said kernel comprises a circular kernel.
8. The digital image processing device of claim 1 , wherein said third image comprises a copy of said second image modified by replacing the saturated intensity values with the extrapolated values.
9. The digital image processing device of claim 1 , wherein said third image comprises said second image modified by replacing the saturated intensity values with the extrapolated values.
10. The digital image processing device of claim 1 , wherein said re-scaling comprises scaling said blurred portion of said third image to a range associated with said second image.
11. A method for creating blur in an image acquired with a digital camera for printing, image processing or analysis, or electronic storage, transmission or display, or combinations thereof, said method comprising:
(a) acquiring a first image of a scene taken at a first exposure level;
(b) acquiring a second image of nominally the same scene taken at a second exposure level greater than said first exposure level, wherein at least one region of said second image includes one or more pixels having saturated intensity values, and wherein one or more corresponding pixels of the first image do not have saturated intensity values;
(c) for at least one of said saturated pixels, extrapolating one or more values from said first image;
(d) generating a third image comprising pixels of said second image having non-saturated values, and pixels having said one or more extrapolated values;
(e) bluffing at least a portion of the third image; and
(f) re-scaling the blurred portion of the third image.
12. The method of claim 11 , further comprising:
determining one or more portions of said third image which correspond to foreground of the image and portions which correspond to background of the image; and
blurring said background portions.
13. The method of claim 11 , wherein said blurring of said third image is performed by applying at least one convolution kernel to said at least one portion.
14. The method of claim 11 , wherein said third image comprises said second image modified by replacing the saturated intensity values with the extrapolated values.