Otsify

Otsify (pron. [ˈoː.tsɪ.faɪ]) is a simple CLI tool for otsifying images, just kidding i.e. converting any image into black&white.

Etymology

The name is a portmanteau of the surname Ōtsu (see Description) and the suffix -ify (as in simple (adj) > simplify (v)). Grammatically, it is a verb, so it can be used as in "Wait a second! I haven't otsified this image yet.".

Description

The program uses Otsu's method so as to threshold an image automatically. Afterwards, if the -i flag is used, it will filter the "isolated" pixels, thus visually explained:

# = black
· = white

# # #     # # #
# · # ==> # # #
# # #     # # #

· · ·     · · ·
· # · ==> · · ·
· · ·     · · ·

This helps shrink the output image file size, because of how the .png format works. Otsu's method leaves many of such pixels on images that either have a lot of noise or don't have a strongly bimodal gray histogram. So it is particularly helpful on those kinds of images.

TODO

Brainstorm of new features:

• --colored or --rgb or -c: this flag would otsify each RGB channel individually.

Installation

Download the binary which suits your operating system & run it from the command line. Otherwise, þou canst build it from source.

Usage

Pass as CLI arguments the names of the input and optional output image files. If no output name is passed, the default is generated from the input, e.g. from example.jpg will result to example_otsu.png. Output files must be png.

• Windows: otsify.exe [options] example.jpg output.png
• Linux: ./otsify [options] example.jpg output.png

Options

• -h, --help: Print help information
• -q, --quiet: Print fatal errors only
• -i: Remove isolated pixels

License

This software is licensed under the GPLv3.