json-to-mask

json-to-mask converts a Labelme JSON file to a mask.

v0.1.2 (2025-03-28): Supports shape_type="mask".

Usage

As the argument, you can pass either a JSON file or directory of JSON files.

labelmetk json-to-mask [OPTIONS] FILE_OR_DIR...

To customize the behavior, use the following options:

• --exclude-labels TEXT: Labels to exclude. If you have labels you’d like to exclude (e.g., __ignore__ label for the region you want to skip labeling) pass these into this option (e.g., --exclude-labels __ignore__).
• --browse: Browse images on a browser. If you pass this option, the command opens the browser to show images as an table.
• --include-labels TEXT: Labels to only include. This is opposite to --exclude-labels option and can’t be used together.

Example: Convert a JSON file

If you only have a single JSON file, pass it to the command:

labelmetk json-to-mask small_dataset/2011_000003.json

to get a mask image:

Example: Convert a directory of JSON files

If you have multiple JSON files in a directory, pass the directory to the command:

labelmetk json-to-mask small_dataset

to get a mask image for each:

Example: Exclude some labels

If you’d like to exclude some of the labels when creating a mask, pass --exclude-labels:

labelmetk json-to-mask small_dataset --exclude-labels __ignore__

You can see the difference from the previous example:

Example: Include only some labels

If you’d like to only show some labels (e.g., person), pass --include-labels:

labelmetk json-to-mask small_dataset --include-labels person

You will get the mask only of "person" label annotations:

Example: Browse the result in a browser:

If you instantly browse the result on a browser, pass --browse (or -b)

labelmetk json-to-mask small_dataset --browse

It will show the output images as a table: