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Image Super-Resolution for Anime-Style Art

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Statistics on waifu2x

Number of watchers on Github 18837
Number of open issues 108
Average time to close an issue 29 days
Main language Lua
Average time to merge a PR 2 days
Open pull requests 6+
Closed pull requests 6+
Last commit about 2 months ago
Repo Created about 5 years ago
Repo Last Updated 15 days ago
Size 693 MB
Homepage http://waifu2x.ud...
Organization / Authornagadomi
Latest Releasev0.13.2
Page Updated
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Image Super-Resolution for Anime-style art using Deep Convolutional Neural Networks. And it supports photo.

The demo application can be found at http://waifu2x.udp.jp/ .

Note that I only provide this website and this repository. Other software or website claiming waifu2x has nothing to do with me.


Click to see the slide show.



waifu2x is inspired by SRCNN [1]. 2D character picture (HatsuneMiku) is licensed under CC BY-NC by piapro [2].

  • [1] Chao Dong, Chen Change Loy, Kaiming He, Xiaoou Tang, Image Super-Resolution Using Deep Convolutional Networks, http://arxiv.org/abs/1501.00092
  • [2] For Creators, http://piapro.net/en_for_creators.html

Public AMI


Third Party Software


If you are a windows user, I recommend you to use waifu2x-caffe(Just download from releases tab), waifu2x-ncnn-vulkan or waifu2x-conver-cpp.





LuaRocks packages (excludes torch7's default packages)

  • lua-csnappy
  • md5
  • uuid
  • csvigo
  • turbo


Setting Up the Command Line Tool Environment

(on Ubuntu 16.04)

Install CUDA

See: NVIDIA CUDA Getting Started Guide for Linux

Download CUDA

sudo dpkg -i cuda-repo-ubuntu1404_7.5-18_amd64.deb
sudo apt-get update
sudo apt-get install cuda

Install Package

sudo apt-get install libsnappy-dev
sudo apt-get install libgraphicsmagick1-dev
sudo apt-get install libssl1.0-dev # for web server

Note: waifu2x requires little-cms2 linked graphicsmagick. if you use macOS/homebrew, See #174.

Install Torch7

See: Getting started with Torch.

  • For CUDA9.x/CUDA8.x, see #222
  • For CUDA10.x, see #253

Getting waifu2x

git clone --depth 1 https://github.com/nagadomi/waifu2x.git

and install lua modules.

cd waifu2x


Testing the waifu2x command line tool.

th waifu2x.lua

Web Application

th web.lua

View at: http://localhost:8812/

Command line tools

Notes: If you have cuDNN library, than you can use cuDNN with -force_cudnn 1 option. cuDNN is too much faster than default kernel. If you got GPU out of memory error, you can avoid it with -crop_size option (e.g. -crop_size 128).

Noise Reduction

th waifu2x.lua -m noise -noise_level 1 -i input_image.png -o output_image.png
th waifu2x.lua -m noise -noise_level 0 -i input_image.png -o output_image.png
th waifu2x.lua -m noise -noise_level 2 -i input_image.png -o output_image.png
th waifu2x.lua -m noise -noise_level 3 -i input_image.png -o output_image.png

2x Upscaling

th waifu2x.lua -m scale -i input_image.png -o output_image.png

Noise Reduction + 2x Upscaling

th waifu2x.lua -m noise_scale -noise_level 1 -i input_image.png -o output_image.png
th waifu2x.lua -m noise_scale -noise_level 0 -i input_image.png -o output_image.png
th waifu2x.lua -m noise_scale -noise_level 2 -i input_image.png -o output_image.png
th waifu2x.lua -m noise_scale -noise_level 3 -i input_image.png -o output_image.png

Batch conversion

find /path/to/imagedir -name "*.png" -o -name "*.jpg" > image_list.txt
th waifu2x.lua -m scale -l ./image_list.txt -o /path/to/outputdir/prefix_%d.png

The output format supports %s and %d(e.g. %06d). %s will be replaced the basename of the source filename. %d will be replaced a sequence number. For example, when input filename is piyo.png, %s_%03d.png will be replaced piyo_001.png.

See also th waifu2x.lua -h.

Using photo model

Please add -model_dir models/photo to command line option, if you want to use photo model. For example,

th waifu2x.lua -model_dir models/photo -m scale -i input_image.png -o output_image.png

Video Encoding

* avconv is alias of ffmpeg on Ubuntu 14.04.

Extracting images and audio from a video. (range: 00:09:00 ~ 00:12:00)

mkdir frames
avconv -i data/raw.avi -ss 00:09:00 -t 00:03:00 -r 24 -f image2 frames/%06d.png
avconv -i data/raw.avi -ss 00:09:00 -t 00:03:00 audio.mp3

Generating a image list.

find ./frames -name "*.png" |sort > data/frame.txt

waifu2x (for example, noise reduction)

mkdir new_frames
th waifu2x.lua -m noise -noise_level 1 -resume 1 -l data/frame.txt -o new_frames/%d.png

Generating a video from waifu2xed images and audio.

avconv -f image2 -framerate 24 -i new_frames/%d.png -i audio.mp3 -r 24 -vcodec libx264 -crf 16 video.mp4

Train Your Own Model

Note1: If you have cuDNN library, you can use cudnn kernel with -backend cudnn option. And, you can convert trained cudnn model to cunn model with tools/rebuild.lua.

Note2: The command that was used to train for waifu2x's pretrained models is available at appendix/train_upconv_7_art.sh, appendix/train_upconv_7_photo.sh. Maybe it is helpful.

Data Preparation

Genrating a file list.

find /path/to/image/dir -name "*.png" > data/image_list.txt

You should use noise free images. In my case, waifu2x is trained with 6000 high-resolution-noise-free-PNG images.

Converting training data.

th convert_data.lua

Train a Noise Reduction(level1) model

mkdir models/my_model
th train.lua -model_dir models/my_model -method noise -noise_level 1 -test images/miku_noisy.png
# usage
th waifu2x.lua -model_dir models/my_model -m noise -noise_level 1 -i images/miku_noisy.png -o output.png

You can check the performance of model with models/my_model/noise1_best.png.

Train a Noise Reduction(level2) model

th train.lua -model_dir models/my_model -method noise -noise_level 2 -test images/miku_noisy.png
# usage
th waifu2x.lua -model_dir models/my_model -m noise -noise_level 2 -i images/miku_noisy.png -o output.png

You can check the performance of model with models/my_model/noise2_best.png.

Train a 2x UpScaling model

th train.lua -model upconv_7 -model_dir models/my_model -method scale -scale 2 -test images/miku_small.png
# usage
th waifu2x.lua -model_dir models/my_model -m scale -scale 2 -i images/miku_small.png -o output.png

You can check the performance of model with models/my_model/scale2.0x_best.png.

Train a 2x and noise reduction fusion model

th train.lua -model upconv_7 -model_dir models/my_model -method noise_scale -scale 2 -noise_level 1 -test images/miku_small.png
# usage
th waifu2x.lua -model_dir models/my_model -m noise_scale -scale 2 -noise_level 1 -i images/miku_small.png -o output.png

You can check the performance of model with models/my_model/noise1_scale2.0x_best.png.


( Docker image is available at https://hub.docker.com/r/nagadomi/waifu2x )

Requires nvidia-docker.

docker build -t waifu2x .
docker run --gpus all -p 8812:8812 waifu2x th web.lua
docker run --gpus all -v `pwd`/images:/images waifu2x th waifu2x.lua -force_cudnn 1 -m scale -scale 2 -i /images/miku_small.png -o /images/output.png

Note that running waifu2x in without JIT caching is very slow, which is what would happen if you use docker. For a workaround, you can mount a host volume to the CUDA_CACHE_PATH, for instance,

docker run --gpus all -v $PWD/ComputeCache:/root/.nv/ComputeCache waifu2x th waifu2x.lua --help
waifu2x open issues Ask a question     (View All Issues)
  • almost 4 years [suggest] Residual Learning?
  • about 4 years non-deterministic result when using cuDNN and upconv_7
  • about 4 years waifu displays in the wrong language
  • about 4 years Mesh style artifacts on new scale 2x model
  • about 4 years [Idea] Training using vector graphics
  • about 4 years [Question] Is it possible to freely scale? example: 2.5x, 3.0x, 4.1x etc.
  • about 4 years Waifu2x in real time
  • about 4 years Method Not Allowed
  • about 4 years Two questions about training process
  • over 4 years high performance version?
  • over 4 years Add TTA mode in waifu2x.udp.jp?
  • over 4 years Gif error
  • over 4 years architecture question
  • over 4 years [Overview] Models differences
  • over 4 years Use original filename for output file.
  • over 4 years Failure to work on my HP z400 & HP z820
  • over 4 years photo model saturation
  • over 4 years Failing on Mac OS X 10.11
  • over 4 years Feature suggestion: Dither removal
  • over 4 years Large file in git repo
  • about 5 years If you plan to share anime episodes after upscaling using this, please read.
  • about 5 years Perceptually uniform colorspace processing?
  • about 5 years web.lua crashed after 10 hours runtime
  • about 5 years Training questions
waifu2x open pull requests (View All Pulls)
  • Update ru.yml
  • Added German Translation
  • BLEH
  • Update fr.yml
  • Update install_lua_modules.sh
  • Added Hideri
waifu2x list of languages used
waifu2x latest release notes
v0.13.2 v0.13.2

Master branch at 2018/11/18.

v0.13.1 v0.13.1
  • Fixed mesh-like artifact on art model #125
  • Fixed wrong format in upconv_7/art/noise0_scale2.0x.t7 (cudnn -> cunn)
v0.13 v0.13
  • Added new upscaling model (models/upconv_7)
  • Added support for user method (universal filter)
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