### 4.2. Antialias

#### 4.2.1. Overview

This filter reduces alias effects (see Anti-aliasing) using the Scale3X edge-extrapolation algorithm.

Scale3X is derived from Scale2X, which is a graphics effect to increase the size of small bitmaps guessing the missing pixels without interpolating pixels and blurring the images.[8] Scale2X was originally developed to improve the quality of old Arcade and PC games with a low video resolution played with video hardware like TVs, Arcade monitors, PC monitors and LCD screens.[9]

The Antialias filter works as follows:

The Antialias filter works as follows: for every pixel, the filter expands the original pixel in 9 (3×3) new pixels according to the Scale3X algorithm, using the colors of the pixel and its 8 adjacent pixels (extrapolation); then it subsamples the new pixels to a weighted average pixel.

#### 4.2.2. Activating the Filter

This filter is found in the main menu under Filters → Enhance → Antialias.

#### 4.2.3. Examples

The following examples illustrate the effect on some patterns. The small squares are one pixel in size (zoom 16:1).

Original image (zoom 16:1)

“Antialias” applied (zoom 16:1)

[8] [SCALE2X].

[9] [AdvanceMAME].

4. Enhance Filters |  | 4.3. Deinterlace

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