Image scaling

According to the theorem, downsampling to a smaller image from a higher-resolution original can only be carried out after applying a suitable 2D anti-aliasing filter to prevent aliasing artifacts.

Although this is desirable for continuous-tone images, this algorithm reduces contrast (sharp edges) in a way that may be undesirable for line art.

[citation needed] Sinc resampling, in theory, provides the best possible reconstruction for a perfectly bandlimited signal.

In practice, the assumptions behind sinc resampling are not completely met by real-world digital images.

[citation needed] One weakness of bilinear, bicubic, and related algorithms is that they sample a specific number of pixels.

Simple interpolation based on the Fourier transform pads the frequency domain with zero components (a smooth window-based approach would reduce the ringing).

[5] A 2013 analysis found that DCCI had the best scores in peak signal-to-noise ratio and structural similarity on a series of test images.

Demonstration of conventional vs. waifu2x upscaling with noise reduction, using a detail of Phosphorus and Hesperus by Evelyn De Morgan.

[Click image for full size] AI-driven software such as the MyHeritage Photo Enhancer allows detail and sharpness to be added to historical photographs, where it is not present in the original.

This application is the magnification of images for home theaters for HDTV-ready output devices from PAL-Resolution content, for example, from a DVD player.

As pixel-art graphics are usually low-resolution, they rely on careful placement of individual pixels, often with a limited palette of colors.

This results in graphics that rely on stylized visual cues to define complex shapes with little resolution, down to individual pixels.

Since a typical application is to improve the appearance of fourth-generation and earlier video games on arcade and console emulators, many are designed to run in real time for small input images at 60 frames per second.

[citation needed] Such filters are currently used in commercial emulators on Xbox Live, Virtual Console, and PSN to allow classic low-resolution games to be more visually appealing on modern HD displays.

FSR standardized presets are not enforced, and some titles such as Dota 2 offer resolution sliders.