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Welcome to the Anime4K wiki!

Here you will find information about each specific shader included in Anime4K, their effects and their underlying algorithm.

All shaders fall in one or many of these specific categories:

• Upscale shaders (Performs super-resolution. Increases (usually double) image size with the expectation that the low resolution image is artifact-free. I.e. No noise, blur or any other degradation.)

  • High quality CNN shaders (M/L/UL variants)
  • Fast DoG shader. It is effectively a repurposed deblur shader. We assume that bilinear upscaling is similar to a gaussian kernel degradation. See the deblur shaders section.
  • The original Anime4K algorithm. Is also effectively a deblur shader but designed to handle the specific case of blur caused by bilinear upscaling.

• Deblur shaders (Performs super-resolution. Decreases blur in an image with the expectation that it is degraded with a gaussian kernel. Image size is left unchanged.)

  • Difference of Gaussians (DoG) deblur shader. Performs non-linear residual enhancement with clamping to prevent overshoot. The power function used turns it from a simple sharpen filter to a deblur filter.
  • The original Anime4K algorithm repurposed as a deblur shader. We assume that a gaussian kernel degradation is similar to the blur produced by bilinear upscaling.
  • CNN upscalers repurposed as a deblur shader (M/L variants). Similar to DoG but the residual is obtained using the CNNs.

• Denoise shaders (Performs denoising. Decrease the noise level in an image. Different shaders have different expectation of the noise distribution.)

• Resampling artifact removal shaders (Tries to reduce the magnitude of resampling artifacts caused by non-linear resampling. E.g. ringing, aliasing.)

• Perceptual enhancement shaders (Enhances perceptual quality by altering the image in some way.)

• Mixed shaders (A shader containing a mix of the above for better performance or image quality.)

  • The DTD shader (Short for Darken-Thin-Deblur shader)