Computer graphics anti-aliasing method using a partitioned look-up table

• US 5,555,359 A
• Filed: 11/28/1994
• Issued: 09/10/1996
• Est. Priority Date: 11/30/1993
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Wee, Young-cheul, Choi, Sang-gil, Cho, Jun-hyoung
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/348,130
• Time in Patent Office: 652 Days
• Field of Search: 395/141, 395/126-132, 395/133, 395/135, 395/143, 395/162, 395/163
• US Class Current: 345/441
• CPC Class Codes: G06T 2200/12 involving antialiasing
• CPC Class Codes: G06T 5/20 using local operators

Abstract

An anti-aliasing method greatly reduces the required size of the look-up table (LUT) memory space. The LUT memory is divided into four partitions and the four partitions are partitioned in parallel. This method allows for a great reduction in the amount of memory which needs to be incorporated into an application-specific integrated circuit (ASIC) which results in lower costs.

Claims

1. An anti-aliasing method using a partitioned LUT having sub-LUTs;

the method comprising the steps of;

dividing a pixel into four sub-blocks;

obtaining a sub-block distance for each sub-block from the center of each of said four sub-blocks to a straight line of the edge of a predetermined polygon, using a pixel distance from the center of said pixel to said straight line and the slope of said straight line; and

respectively generating sub-masks stored in said sub-LUTs for the respective sub-blocks by inputting the respective sub-block distances and said slope, to said sub-LUTs.

2. An anti-aliasing method using partitioned LUTs as claimed in claim 1, wherein said sub-block distance obtaining step is performed by adding said pixel distance with the respective four sub-block distance estimated values defined in the following equations, ##EQU2## where Δ

d₁, Δ

d₂, Δ

d₃, and Δ

d₄ are first through fourth estimated values of sub-block distances, d_ex is the pixel distance depending on the increment of the X axis, and d_ey is the pixel distance depending on the increment of the Y axis.

3. An anti-aliasing method using a partitioned LUT as claimed in claim 2, wherein said sub-mask generating step comprises of the steps of:

obtaining a first sub-mask from a predetermined first sub-LUT which receives said d_ex, the sign of said d_ey value, and a first sub-block distance obtained by adding said pixel distance with said first estimated values of sub-block distance;

obtaining a second sub-mask from a predetermined second sub-LUT which receives said d_ex, the sign of said d_ey value, and a second sub-block distance obtained by adding said pixel distance with said second estimated values of sub-block distance;

obtaining a third sub-mask from a predetermined third sub-LUT which receives said d_ex, the sign of said d_ey value, and a third sub-block distance obtained by adding said pixel distance with said third estimated values of sub-block distance; and

obtaining a fourth sub-mask from a predetermined fourth sub-LUT which receives said d_ex, the sign of said d_ey value, and a fourth sub-block distance obtained by adding said pixel distance with said fourth estimated values of sub-block distance.

4. An anti-aliasing method using a partitioned LUT as claimed in claim 3, wherein each of said first to fourth sub-LUTs receive the sign of said d_ex value and said d_ey value, instead of said d_ex and the sign of said d_ey.

5. An anti-aliasing apparatus for use in an electronic graphics system wherein each pixel is divided into a plurality of sub-blocks, the apparatus comprising:

a plurality of distance determining means, one for each respective sub-block, for obtaining a sub-block distance for each sub-block from the center of the respective sub-block to a straight line of an edge of a predetermined polygon, using a pixel distance from the center of said pixel to said straight line and the slope of said straight line;

a plurality of sub-mask generating means, one for each respective sub-block, for generating a sub-mask for the respective sub-block and coupled to the respective distance determining means to receive the respective sub-block distance, said sub-mask being generated using the respective sub-block distance and said slope.