Butteraugli

ImageQualityAssessment

• https://github.com/google/butteraugli

• Guetzli/Butteraugli

• Build

   bazel build -c opt //:butteraugli

• Usage

  Usage: butteraugli {image1.(png|jpg|jpeg)} {image2.(png|jpg|jpeg)} [heatmap.ppm]

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• SSIM / MSSIM vs MSE
  • https://encode.ru/threads/2395-SSIM-MSSIM-vs-MSE

    Jyrki Alakuijala  Jyrki Alakuijala
    an anyone here comment on SSIM vs MSE ?
    Does SSIM indeed perform better than MSE ?
    Thanks so much,
    Aaron
    We have just opensourced butteraugli, a new non-parametric method for estimating the noticeability of lossy compression artefacts.
    https://github.com/google/butteraugli

• https://news.ycombinator.com/item?id=13889137

  JyrkiAlakuijala 11 months ago | parent | favorite | on: Guetzli: A New Open-Source JPEG Encoder
  This comes through the internal use of butteraugli -- and depending the quantization decisions on butteraugli.
  Butteraugli uses a 8x8 FFT, but computes this every 3x3 pixel creating coverage at block boundaries.
  In later stages of butteraugli calculation values are aggregated from an even larger area.
  Block boundary artefacts are taken into account by this and impact quantization decisions.

Butteraugli operates neither in RGB nor YUV. It has a new color space that is a hybrid of tri-chromatic colors and opponent colors.
Black-to-yellow and red-to-green are opponent, but blue is modeled closer to tri-chromatic.
In more simple explanation it is possible to think of it as follows:
first apply inverse gamma correction, second apply a 3x4 transform for rgb, third apply gamma correction, fourth calculate r - g, r + g and keep blue separate.

関連

• Guetzli
• SSIM