https://github.com/google/butteraugli

butteraugli estimates the psychovisual difference between two images
https://github.com/google/butteraugli

Last synced: about 1 month ago
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butteraugli estimates the psychovisual difference between two images

• Host: GitHub
• URL: https://github.com/google/butteraugli
• Owner: google
• License: apache-2.0
• Archived: true
• Created: 2016-02-04T13:13:40.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2022-09-09T07:22:58.000Z (about 2 years ago)
• Last Synced: 2024-09-21T19:32:22.771Z (about 2 months ago)
• Language: C++
• Homepage:
• Size: 6.19 MB
• Stars: 1,962
• Watchers: 85
• Forks: 138
• Open Issues: 39
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-bazel - butteraugli

README

        
# butteraugli

> A tool for measuring perceived differences between images

## Introduction

Butteraugli is a project that estimates the psychovisual similarity of two

images. It gives a score for the images that is reliable in the domain of barely

noticeable differences. Butteraugli not only gives a scalar score, but also

computes a spatial map of the level of differences.

One of the main motivations for this project is the statistical differences in

location and density of different color receptors, particularly the low density

of blue cones in the fovea. Another motivation comes from more accurate modeling

of ganglion cells, particularly the frequency space inhibition.

## Use

Butteraugli can work as a quality metric for lossy image and video compression.

On our small test corpus butteraugli performs better than our implementations of

the reference methods, psnrhsv-m, ssim, and our yuv-color-space variant of ssim.

One possible use is to define the quality level setting used in a jpeg

compressor, or to compare two or more compression methods at the same level of

psychovisual differences.

Butteraugli is intended to be a research tool more than a practical tool for

choosing compression formats. We don't know how well butteraugli performs with

major deformations -- we have mostly tuned it within a small range of quality,

roughly corresponding to jpeg qualities 90 to 95.

## Interface

Only a C++ interface is provided. The interface takes two images and outputs a

map together with a scalar value defining the difference. The scalar value can

be compared to two reference values that divide the value space into three

experience classes: 'great', 'acceptable' and 'not acceptable'.

## Build instructions

Install [Bazel](http://bazel.build) by following the

[instructions](https://www.bazel.build/docs/install.html). Run `bazel build -c opt

//:butteraugli` in the directory that contains this README file to build the

[command-line utility](#cmdline-tool). If you want to use Butteraugli as a

library, depend on the `//:butteraugli_lib` target.

Alternatively, you can use the Makefile provided in the `butteraugli` directory,

after ensuring that [libpng](http://www.libpng.org/) and

[libjpeg](http://ijg.org/) are installed. On some systems you might need to also

install corresponding `-dev` packages.

The code is portable and also compiles on Windows after defining

`_CRT_SECURE_NO_WARNINGS` in the project settings.

## Command-line utility {#cmdline-tool}

Butteraugli, apart from the library, comes bundled with a comparison tool. The

comparison tool supports PNG and JPG images as inputs. To compare images, run:

```

butteraugli image1.{png|jpg} image2.{png|jpg}

```

The tool can also produce a heatmap of differences between images. The heatmap

will be output as a PNM image. To produce one, run:

```

butteraugli image1.{png|jpg} image2.{png|jpg} heatmap.pnm

```