Need help with sewar?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.

About the developer

360 Stars 46 Forks MIT License 76 Commits 9 Opened issues


All image quality metrics you need in one package.

Services available


Need anything else?

Contributors list

# 183,144
56 commits
# 365,673
14 commits
# 333,012
1 commit

Buy Me A Coffee


Build Status codecov

Sewar is a python package for image quality assessment using different metrics. You can check documentation here.

Implemented metrics

  • [x] Mean Squared Error (MSE)
  • [x] Root Mean Sqaured Error (RMSE)
  • [x] Peak Signal-to-Noise Ratio (PSNR) [1]
  • [x] Structural Similarity Index (SSIM) [1]
  • [x] Universal Quality Image Index (UQI) [2]
  • [x] Multi-scale Structural Similarity Index (MS-SSIM) [3]
  • [x] Erreur Relative Globale Adimensionnelle de Synthèse (ERGAS) [4]
  • [x] Spatial Correlation Coefficient (SCC) [5]
  • [x] Relative Average Spectral Error (RASE) [6]
  • [x] Spectral Angle Mapper (SAM) [7]
  • [x] Spectral Distortion Index (D_lambda) [8]
  • [x] Spatial Distortion Index (D_S) [8]
  • [x] Quality with No Reference (QNR) [8]
  • [x] Visual Information Fidelity (VIF) [9]
  • [x] Block Sensitive - Peak Signal-to-Noise Ratio (PSNR-B) [10]


  • [ ] Add command-line support for No-reference metrics


Just as simple as

pip install sewar

Example usage

a simple example to use UQI ```python

from sewar.full_ref import uqi uqi(img1,img2) 0.9586952304831419 ```

Example usage for command line interface

sewar [metric] [GT path] [P path] (any extra parameters)

An example to use SSIM

[email protected]:~$ sewar ssim images/ground_truth.tif images/deformed.tif -ws 13
ssim : 0.8947009811410856
Available metrics list
mse, rmse, psnr, rmse_sw, uqi, ssim, ergas, scc, rase, sam, msssim, vifp, psnrb 


Special thanks to @sachinpuranik99 and @sunwj.


[1] "Image quality assessment: from error visibility to structural similarity." 2004)
[2] "A universal image quality index." (2002)
[3] "Multiscale structural similarity for image quality assessment." (2003)
[4] "Quality of high resolution synthesised images: Is there a simple criterion?." (2000)
[5] "A wavelet transform method to merge Landsat TM and SPOT panchromatic data." (1998)
[6] "Fusion of multispectral and panchromatic images using improved IHS and PCA mergers based on wavelet decomposition." (2004)
[7] "Discrimination among semi-arid landscape endmembers using the spectral angle mapper (SAM) algorithm." (1992)
[8] "Multispectral and panchromatic data fusion assessment without reference." (2008)
[9] "Image information and visual quality." (2006)
[10] "Quality Assessment of Deblocked Images" (2011)

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.