image-compare 0.1.1

Image comparison library based upon the image crate. Currently it provides SSIM and RMS for comparing grayscale images with a friendly license.
Documentation
# image-compare
[![Documentation](https://docs.rs/image-compare/badge.svg)](https://docs.rs/image-compare)
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Simple image comparison in rust based on the image crate

Note that this crate is heavily work in progress. Algorithms are neither cross-checked not particularly fast yet.
Everything is implemented in plain CPU with no SIMD or GPU usage.

Supported now:
- Comparing grayscale images
  - By RMS - score is calculated by: <img src="https://render.githubusercontent.com/render/math?math=1-\sqrt{\frac{(\sum_{x,y=0}^{x,y=w,h}\left(f(x,y)-g(x,y)\right)^2)}{w*h}}"> 
  - By MSSIM
    - SSIM is implemented as described on [wikipedia]https://en.wikipedia.org/wiki/Structural_similarity: <img src="https://render.githubusercontent.com/render/math?math=\mathrm{SSIM}(x,y)={\frac {(2\mu _{x}\mu _{y}+c_{1})(2\sigma _{xy}+c_{2})}{(\mu _{x}^{2}+\mu _{y}^{2}+c_{1})(\sigma _{x}^{2}+\sigma _{y}^{2}+c_{2})}}"> 
    - MSSIM is calculated by using 8x8 pixel windows for SSIM and averaging over the results
  
Planned:
- Histogram comparisons for grayscale and colored images
- SIMD for RMS and MSSIM