CLIAMS:WE CLAIM

1. A method of image scaling, comprising:
determining one or more filter phases based on a vertical target grid distance and a horizontal target grid distance; and
scaling, by hardware circuitry, an input image using filter coefficients corresponding to the one or more filters phases to output a target image,
wherein:
the horizontal target grid distance is based on a ratio of a number of horizontal filter phases and a horizontal scaling ratio, and
the vertical target grid distance is based on a ratio of a number of vertical filter phases and a vertical scaling ratio.

2. The method of claim 1, wherein the horizontal scaling ratio represents a ratio of a number of pixels per line in the target image and a number of pixels per line in the input image.

3. The method of claim 1, wherein the vertical scaling ratio represents a ratio of a number of lines in the target image and a number of lines in the input image.

4. The method of claim 1, wherein determining one or more filter phases based on a vertical target grid distance and a horizontal target grid distance includes:
determining, based on the vertical target grid distance, a vertical target grid cumulative distance for a first line in the target image; and
determining, based on the horizontal target grid distance, a horizontal target grid cumulative distance for a first pixel in the first line in the target image.

5. The method of claim 4, wherein determining one or more filter phases based on a vertical target grid distance and a horizontal target grid distance further includes:
determining, for the first line, a first vertical filter phase based on the vertical target grid cumulative distance for the first line; and
determining, for the first pixel, a first horizontal filter phase based on the horizontal target grid cumulative distance for the first pixel.
6. The method of claim 5, wherein scaling an input image includes:
determining, based on the vertical target grid cumulative distance, a first set of lines from the input image to be buffered for generating the first line; and
generating a vertically filtered first line based on the first set of lines and filter coefficients corresponding to the first vertical filter phase.

7. The method of claim 6, wherein scaling an input image further includes:
determining, based on the horizontal target grid cumulative distance, a first set of pixels from the vertically filtered first line to be buffered for generating the first line; and
generating the first pixel based on the first set of pixels and filter coefficients corresponding to the first horizontal filter phase.

8. A system for image scaling, comprising:
a memory storing instructions;
one or more hardware processors configured to execute the instructions to:
determine one or more filter phases based on a vertical target grid distance and a horizontal target grid distance; and
scale an input image using filter coefficients corresponding to the one or more filters phases to output a target image,
wherein:
the horizontal target grid distance is based on a ratio of a number of horizontal filter phases and a horizontal scaling ratio, and
the vertical target grid distance is based on a ratio of a number of vertical filter phases and a vertical scaling ratio.

9. The system of claim 8, wherein the horizontal scaling ratio represents a ratio of a number of pixels per line in the target image and a number of pixels per line in the input image.

10. The system of claim 8, wherein the vertical scaling ratio represents a ratio of a number of lines in the target image and a number of lines in the input image.

11. The system of claim 8, wherein the one or more hardware processors are configured to determine one or more filter phases based on a vertical target grid distance and a horizontal target grid distance by:
determining, based on the vertical target grid distance, a vertical target grid cumulative distance for a first line in the target image; and
determining, based on the horizontal target grid distance, a horizontal target grid cumulative distance for a first pixel in the first line in the target image.

12. The system of claim 11, wherein the one or more hardware processors are further configured to determine one or more filter phases based on a vertical target grid distance and a horizontal target grid distance by:
determining, for the first line, a first vertical filter phase based on the vertical target grid cumulative distance for the first line; and
determining, for the first pixel, a first horizontal filter phase based on the horizontal target grid cumulative distance for the first pixel.

13. The system of claim 12, wherein the one or more hardware processors are configured to scale an input image by:
determining, based on the vertical target grid cumulative distance, a first set of lines from the input image to be buffered for generating the first line; and
generating a vertically filtered first line based on the first set of lines and filter coefficients corresponding to the first vertical filter phase.

14. The system of claim 13, wherein the one or more hardware processors are further configured to scale the input image by:
determining, based on the horizontal target grid cumulative distance, a first set of pixels from the vertically filtered first line to be buffered for generating the first line; and
generating the first pixel based on the first set of pixels and filter coefficients corresponding to the first horizontal filter phase.

15. A non-transitory computer-readable storage medium storing instructions which when executed by at least one processor enable the at least one processor to execute a method of image scaling, the method comprising:
determining one or more filter phases based on a vertical target grid distance and a horizontal target grid distance; and
scaling, by the at least one processor, an input image using filter coefficients corresponding to the one or more filters phases to output a target image,
wherein:
the horizontal target grid distance is based on a ratio of a number of horizontal filter phases and a horizontal scaling ratio, and
the vertical target grid distance is based on a ratio of a number of vertical filter phases and a vertical scaling ratio.

Dated this 27th day of March 2014
Sravan Kumar Gampa
Of K&S Partners
Agent for the Applicant
,TagSPECI:TECHNICAL FIELD
The disclosure generally relates to image processing and, more particularly, to image scaling using a poly-phase filter.