US5398079A — Half-pixel interpolation for a motion compensated…

Claim 1

Independent Claim 151 words

A method for processing previous frame data in a motion compensated digital video system to interpolate pixels used in reconstructing a current video frame, comprising the steps of: arranging pixel data from a previous video frame into sub-blocks containing a plurality N of pixels; storing said sub-blocks in a memory to enable the retrieval of at least one sub-block per memory access cycle; retrieving a plurality M of said sub-blocks from said memory in response to a displacement vector associated with a portion of a current video frame, wherein M≦N and said M sub-blocks are retrieved in no more than M memory access cycles; choosing a subset of pixels from said selected plurality of sub-blocks for use in interpolating pixels for said current video frame portion; and processing said subset of pixels over no more than N memory access cycles to provide N interpolated pixels for said current video frame portion.

Claim 2

Independent Claim 151 words

A method for processing previous frame data in a motion compensated digital video system to interpolate pixels used in reconstructing a current video frame, comprising the steps of: arranging pixel data from a previous video frame into sub-blocks containing a plurality N of pixels; storing said sub-blocks in a memory to enable the retrieval of at least one sub-block per memory access cycle; retrieving a plurality M of said sub-blocks from said memory in response to a displacement vector associated with a portion of a current video frame, wherein M≦N and said M sub-blocks are retrieved in no more than M memory access cycles; choosing a subset of pixels from said selected plurality of sub-blocks for use in interpolating pixels for said current video frame portion; and processing said subset of pixels over no more than N memory access cycles to provide N interpolated pixels for said current video frame portion.

Claim 3

Dependent Claim 28 words

A method in accordance with claim 1 wherein N is at least the maximum number of pixels necessary to obtain an interpolated pixel using a desired interpolation algorithm.

Claim 4

Dependent Claim 28 words

A method in accordance with claim 1 wherein said arranging step comprises the step of evenly dividing blocks of pixels from said previous video frame into said sub-blocks.

Claim 5

Dependent Claim 101 words

A method in accordance with claim 1 wherein horizontal, vertical and diagonal interpolation is provided using up to four previous frame pixels to obtain each interpolated current frame pixel, and said processing step comprises the steps of: selecting four pixels from said subset of pixels for use in interpolating a current frame pixel; and averaging two horizontally or vertically spaced pixels of said selected four pixels in response to a horizontal or a vertical interpolation control signal, respectively, or averaging all of the selected four pixels in response to a diagonal interpolation control signal in order to obtain an interpolated pixel.

Claim 6

Dependent Claim 149 words

Apparatus for interpolating pixels used in reconstructing a current video frame from pixels of a previous video frame in a motion compensated digital video system, comprising: memory means for storing sub-blocks, each sub-block containing a plurality N of pixels from said previous video frame; means for retrieving a plurality M of said sub-blocks from said memory means in response to a displacement vector associated with a portion of a current video frame for which pixels are to be interpolated, wherein M≦N and said M sub-blocks are retrieved in no more than M access cycles of said memory means; means for choosing a subset of pixels from said retrieved plurality of sub-blocks for use in interpolating pixels for said current video frame portion; and means for processing said subset of pixels over no more than N memory access cycles to provide N interpolated pixels for said current video frame portion.

Claim 7

Dependent Claim 149 words

Apparatus for interpolating pixels used in reconstructing a current video frame from pixels of a previous video frame in a motion compensated digital video system, comprising: memory means for storing sub-blocks, each sub-block containing a plurality N of pixels from said previous video frame; means for retrieving a plurality M of said sub-blocks from said memory means in response to a displacement vector associated with a portion of a current video frame for which pixels are to be interpolated, wherein M≦N and said M sub-blocks are retrieved in no more than M access cycles of said memory means; means for choosing a subset of pixels from said retrieved plurality of sub-blocks for use in interpolating pixels for said current video frame portion; and means for processing said subset of pixels over no more than N memory access cycles to provide N interpolated pixels for said current video frame portion.

Claim 8

Dependent Claim 27 words

Apparatus in accordance with claim 5 wherein N is at least the maximum number of pixels necessary to obtain an interpolated pixel using a desired interpolation algorithm.

Claim 9

Dependent Claim 29 words

Apparatus in accordance with claim 5 wherein: said portion of a current video frame comprises a block of pixels corresponding in size to an integer number of said sub-blocks.

Claim 10

Dependent Claim 115 words

Apparatus in accordance with claim 5 wherein said processing means provide horizontal, vertical and diagonal interpolation using up to four previous frame pixels to obtain each interpolated current frame pixel, said processing means comprising: means for selecting four pixels from said subset of pixels for use in interpolating a current frame pixel; means for averaging two horizontally or vertically spaced pixels of said selected four pixels in response to a horizontal or a vertical interpolation control signal, respectively, in order to obtain a horizontally or a vertically interpolated pixel; and means for averaging all of the selected four pixels in response to a diagonal interpolation control signal in order to obtain a diagonally interpolated pixel.

Claim 11

Dependent Claim 74 words

Apparatus in accordance with claim 8 wherein: said sub-blocks have a horizontal dimension K and a vertical dimension L; and said selecting means comprise: a plurality K+1 of shift registers, each having L+1 stages for collectively holding said subset of pixels, and multiplexer means coupled to selected outputs of said shift registers for providing a different group of four previous frame pixels from said shift registers to said averaging means each memory access cycle.

Claim 12

Dependent Claim 140 words

Apparatus in accordance with claim 9 wherein each group of previous frame pixels comprises an upper left hand corner pixel P 0 , an upper right hand corner pixel P 1 , a lower right hand corner pixel P 2 , and a lower left hand corner pixel P 3 defining a square, and said averaging means comprise: first means for outputting the sum, divided by two, of pixel P 0 and pixel P 1 in response to said horizontal interpolation control signal; second means for outputting the sum, divided by two, of pixel P 0 and pixel P 3 in response to said vertical interpolation control signal; and third means for outputting the sum, divided by four, of pixels P 0 , P 1 , P 2 , and P 3 in response to said diagonal interpolation control signal.

Claim 13

Dependent Claim 20 words

Apparatus in accordance with claim 10 wherein said first, second and third means comprise conventional add, subtract and multiplexer circuits.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-03-13	1998-09-12	1999-03-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-03-13	2002-09-12	2003-03-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-03-13	2006-09-12	2007-03-14	$7700.00	Window Closed / Lapsed

Half-pixel interpolation for a motion compensated digital video system

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