Waifu2x 
Waifu2x is a ruby wrapper and CLI for waifu2x, which provides Noise Reduction and 2x Upscaling for anime style images.
Installation
Install it from rubygems:
gem install waifu2xOr add to your application's Gemfile:
gem 'waifu2x'and run:
bundle installUsage
# convert image.png with 2x upscaling
Waifu2x.convert('image.png', nil, { scale: 2 })
# convert image.png from remote url
Waifu2x.convert('http://example.net/image.png', nil, { scale: 2 })
# convert image.png to converted.png without noise reduction and with 2x upscaling
Waifu2x.convert('image.png', 'converted.png', { noise: 0, scale: 2 })CLI usage
# convert sample.jpg with 2x upscaling
waifu2x sample.jpg -s 2
# convert sample.jpg from remote url
waifu2x http://example.net/sample.jpg -s 2
# convert sample.jpg to output.jpg without noise reduction and with 2x upscaling
waifu2x sample.jpg output.jpg -n 0 -s 2License
Released under the BSD 2-clause license. See LICENSE.txt for details.