SSIM-X

This is my personal modification to Cloudinary's SSIMULACRA tool.

I'm calling it SSIM-X because SSIMULACRA is a mouthful.

You supply it with an original image and a compressed one, then it gives you a score on the perceived quality of the compressed image. You can also have it generate an edge difference map and a SSIM map to show you the areas most affected by the compression.

Precompiled x64 Window binaries available under Releases.

You can refer to the original Read Me at the bottom for more infomation.

Usage

ssimx path/to/original path/to/compressed [prefix for edge difference and ssim map]

My changes:

• AVIF support.
• Allow comparison between 4 channel images and 3 channel images (a 100% opaque alpha channel is added).
• Allow generation of edge difference map and SSIM map by supplying a 3rd argument.
• More verbose error messages.
• Turned it into a Visual Studio 2022 solution.
• Fixed all warnings.

Compile

• Install visual Studio 2022 and open the solution file.
• Use Vcpkg to install all dependencies (OpenCV and LibAVIF with AOM feature).
  • git clone https://github.com/microsoft/vcpkg (clone the vcpkg repo)
  • cd vcpkg
  • bootstrap-vcpkg.bat (initialize vcpkg)
  • vcpkg install opencv4:x64-windows (install opencv)
  • vcpkg install libavif[aom]:x64-windows (install libavif with aom codec)
  • vcpkg integrate install (integrate with Visual Studio)

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Original Read Me:

SSIMULACRA - Structural SIMilarity Unveiling Local And Compression Related Artifacts

Cloudinary's variant of DSSIM, based on Philipp Klaus Krause's adaptation of Rabah Mehdi's SSIM implementation, using ideas from Kornel Lesinski's DSSIM implementation as well as several new ideas.

This is a perceptual metric designed specifically for scoring image compression related artifacts in a way that correlates well with human opinions. For more information, see http://cloudinary.com/blog/detecting_the_psychovisual_impact_of_compression_related_artifacts_using_ssimulacra

Changes compared to Krause's SSIM implementation:

• Use C++ OpenCV API
• Convert sRGB to linear RGB and then to Lab*, to get a perceptually more accurate color space
• Multi-scale (6 scales)
• Extra penalty for specific kinds of artifacts:
  • local artifacts
  • grid-like artifacts (blockiness)
  • introducing edges where the original is smooth (blockiness / color banding / ringing / mosquito noise)

Known limitations:

• Color profiles are ignored; input images are assumed to be sRGB.
• Both input images need to have the same number of channels (Grayscale / RGB / RGBA)

Build instructions

• Install OpenCV
• Do make

License

May 2016 - Feb 2017, Jon Sneyers [email protected]

Copyright 2017, Cloudinary

SSIMULACRA is licensed under the Apache License, Version 2.0 (the "License"). You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.