Adaptive spatial variant interpolation for image upscaling
First Claim
1. A method comprising:
- determining, via a processor, a symmetry (A) of a scaled pixel in an image based on content characteristics of neighboring pixels in the image;
determining, via the processor, an intensity (k) of a spatial variant interpolation filter based on the symmetry (A);
adjusting, via the processor, the spatial variant interpolation filter based on the intensity (k), wherein adjusting the spatial variant interpolation filter includes determining a warped distance (s′
) based on the symmetry (A) of the scaled pixel and the intensity (k) of the filter response, and adjusting the spatial variant interpolation filter based on the warped distance (s′
); and
applying, via the processor, the spatial variant interpolation filter to interpolate the scaled pixel,wherein determining the intensity (k) of the filter response comprises;
determining whether the symmetry (A) resides within one of a plurality of zones (A0-An); and
setting the intensity (k) to one of a plurality of intensity values (k0-kn) associated with the one of the plurality of zones (A0-An) in which the symmetry (A) lies.
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Abstract
This disclosure describes adaptive spatial variant interpolation (SVI) techniques for image upscaling. In various embodiments, the interpolation techniques described in this disclosure may support low complexity upscaling of image while promoting high image quality, including enhanced sharpness, higher contrast and more accurate interpolation. The interpolation techniques may be applied using generalized finite impulse response (FIR) filters. In some embodiments, the interpolation techniques may be content-adaptive to provide more accurate interpolation while suppressing significant artifacts associated with sharp edges. In addition, the interpolation techniques may be readily applicable to upscaling of color imagery and video, e.g., in both YCbCr (luminance, blue chrominance, red chrominance) and RGB (red, green, blue) formats.
51 Citations
37 Claims
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1. A method comprising:
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determining, via a processor, a symmetry (A) of a scaled pixel in an image based on content characteristics of neighboring pixels in the image; determining, via the processor, an intensity (k) of a spatial variant interpolation filter based on the symmetry (A); adjusting, via the processor, the spatial variant interpolation filter based on the intensity (k), wherein adjusting the spatial variant interpolation filter includes determining a warped distance (s′
) based on the symmetry (A) of the scaled pixel and the intensity (k) of the filter response, and adjusting the spatial variant interpolation filter based on the warped distance (s′
); andapplying, via the processor, the spatial variant interpolation filter to interpolate the scaled pixel, wherein determining the intensity (k) of the filter response comprises; determining whether the symmetry (A) resides within one of a plurality of zones (A0-An); and setting the intensity (k) to one of a plurality of intensity values (k0-kn) associated with the one of the plurality of zones (A0-An) in which the symmetry (A) lies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A device comprising:
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a memory that stores an image; and a processor that determines a symmetry (A) of a scaled pixel in an image based on content characteristics of neighboring pixels in the image, determines an intensity (k) of an interpolation filter based on the symmetry (A), adjusts the interpolation filter based on the intensity (k), and applies the spatial variant interpolation filter to interpolate the scaled pixel, wherein the processor that adjusts the interpolation filter based on the intensity (k) determines a warped distance (s′
) based on the symmetry (A) of the scaled pixel and the intensity (k) of the filter response, and adjusts the spatial variant interpolation filter based on the warped distance (s′
), andwherein the processor determines whether the symmetry (A) resides within one of a plurality of zones (A0-An,), and sets the intensity (k) to one of a plurality of intensity values (k0-kn) associated with the one of the plurality of zones (A0-An) in which the symmetry (A) lies. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A non-transitory computer-readable medium comprising instructions for causing a programmable processor to:
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determine a symmetry (A) of a scaled pixel in an image based on content characteristics of neighboring pixels in the image; determine an intensity (k) of a spatial variant interpolation filter based on the symmetry (A); adjust the spatial variant interpolation filter based on the intensity (k), wherein the instructions that cause the processor to adjust the spatial variant interpolation filter based on the intensity (k) comprise instructions that cause the processor to determine a warped distance (s′
) based on the symmetry (A) of the scaled pixel and the intensity (k) of the filter response, and adjust the spatial variant interpolation filter based on the warped distance (s′
); andapply the spatial variant interpolation filter to interpolate the scaled pixel, wherein the instructions cause the processor to determine whether the symmetry (A) resides within one of a plurality of zones (A0-An), and set the intensity (k) to one of a plurality of intensity values (k0-kn) associated with the one of the plurality of zones (A0-An) in which the symmetry (A) lies. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A device comprising:
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means for determining a symmetry (A) of a scaled pixel in an image based on content characteristics of neighboring pixels in the image; means for determining an intensity (k) of a spatial variant interpolation filter based on the symmetry (A); means for adjusting the spatial variant interpolation filter based on the intensity (k), wherein the means for adjusting includes means for determining a warped distance (s′
) based on the symmetry (A) of the scaled pixel and the intensity (k) of the filter response, and means for adjusting the spatial variant interpolation filter based on the warped distance (s′
); andmeans for applying the spatial variant interpolation filter to interpolate the scaled pixel, wherein the means for determining the intensity (k) of the filter response comprises; means for determining whether the symmetry (A) resides within one of a plurality of zones (A0-An); and means for setting the intensity (k) to one of a plurality of intensity values (k0-kn) associated with the one of the plurality of zones (A0-An) in which the symmetry (A) lies.
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Specification