Methods and systems for picture up-sampling

1. A method for picture up-sampling from a base-layer picture comprising base-layer image samples, base L [•, •], to an enhancement-layer picture comprising enhancement-layer image samples, pred L [•, •], comprising:

defining a position, (xP, yP), for an upper-left sample of a block of said enhancement-layer picture;

deriving a relative location, xB, yB, xB1, yB1, of said block of said enhancement-layer picture in said base-layer picture; and

producing a sample block array, pred L [x, y], wherein said producing comprises:

forming a temporary sample array, temp L [x, y];

deriving an entry in said temporary sample array, wherein said deriving comprises:

calculating a corresponding fractional-sample y-position, yf, in said base-layer picture;

calculating a y-position interpolation center, yInt, based on yf;

calculating a y-position phase based on yf;

obtaining a first set of filter coefficients for a first six-tap filter, wherein said obtaining of said first set of filter coefficients is based on said y-position phase; and

deriving said entry temp L [x, y] according to:

temp L [x, y ]=base L [x, y Int−2]* e[− 2]+base L [x, y Int−1]* e[− 1]+base L [x, y Int]*e[0]+base L [x, y Int+1]* e[ 1]+base L [x, y Int+2]* e[ 2]+base L [x, y Int+3]* e[ 3],

wherein e[−2], e[−1], e[0], e[1], e[2], and e[3] represent said first set of filter coefficients for said first six-tap filter; and

deriving an entry in said sample block array, pred L [x, y], wherein said deriving comprises:

calculating a corresponding fractional-sample x-position, xf, in said base-layer picture;

calculating an x-position interpolation center, xInt, based on xf;

forming an x-position phase based on xf;

obtaining a second set of filter coefficients for a second six-tap filter, wherein said obtaining of said second set of filter coefficients is based on said x-position phase; and

deriving said entry pred L [x, y] according to:

pred L [x, y ]=Clip1 y (( temp L [xInt− 2, y]*e[− 2]+temp L [xInt− 1, y]*e[− 1]+temp L [x, yInt]*e[ 0]+temp L [xInt+ 1, y]*e[ 1]+temp L [xInt+ 2, y]*e[ 2]+temp L [xInt+ 3, y]*e[ 3]+512)/1024),

wherein e[−2], e[−1], e[0], e[1], e[2], and e[3] represent said second set of filter coefficients for said second six-tap filter.

2. The method of claim 1 further comprising defining an interpolation resolution.

3. The method of claim 2 , wherein said interpolation resolution is 1/16 (one-sixteenth) of an image sample.

4. The method of claim 1 , wherein said base-layer image samples comprise luminance samples.

5. The method of claim 1 , wherein said base-layer image samples comprise chrominance samples.

6. The method of claim 1 , wherein said obtaining of said first set of filter coefficients comprises accessing a look-up-table.

7. The method of claim 6 , wherein said look-up-table comprises samples of a Lanczos-windowed sinc function.

8. The method of claim 1 , wherein said obtaining of said second set of filter coefficients comprises accessing a look-up-table.

9. The method of claim 8 , wherein said look-up-table comprises samples of a Lanczos-windowed sinc function.

10. The method of claim 1 , wherein said block is a macroblock of dimension 16 by 16.

11. The method of claim 1 , wherein said block has the same spatial dimensions as said enhancement-layer picture.