woctezuma / VIA2COCO

Convert annotations from VIA to COCO.

VIA2COCO

This repository contains Python code to convert annotations from Oxford's VGG Image Annotator (VIA) to Microsoft's Common Objects in Context (COCO) format.

Installation

• Install the latest version of Python 3.X.

Usage

The simplest usage would be to specify a list of categories.

Caveat:

• categories should have distinct names,
• the order matters, as it will be used to number categories.

import convert as via2coco

input_dir = '/content/data/balloon/train/'
input_json = input_dir + 'via_region_data.json'
categories = ['balloon']

coco_dict = via2coco.convert(
    imgdir=input_dir,
    annpath=input_json,
    categories=categories,
)

By default, the first category is indexed as 1. This can be changed to 0 (or any non-negative integer) as follows:

import convert as via2coco

input_dir = '/content/data/balloon/train/'
input_json = input_dir + 'via_region_data.json'
categories = ['balloon']
first_class_index = 0

coco_dict = via2coco.convert(
    imgdir=input_dir,
    annpath=input_json,
    categories=categories,
    first_class_index=first_class_index,
)

To save the output as a JSON file:

import convert as via2coco

input_dir = '/content/data/balloon/train/'
input_json = input_dir + 'via_region_data.json'
categories = ['balloon']

output_json = input_dir + 'coco_train.json'

coco_dict = via2coco.convert(
    imgdir=input_dir,
    annpath=input_json,
    categories=categories,
    output_file_name=output_json,
)

It is also possible to specify a list of super-categories.

Caveat:

• super-categories can have the same name,
• the lists of categories and super-categories should have the same length,
• the order matters, as it will be used to match categories and super-categories.

import convert as via2coco

input_dir = '/content/data/balloon/train/'
input_json = input_dir + 'via_region_data.json'
categories = ['balloon']

super_categories = ['N/A']

coco_dict = via2coco.convert(
    imgdir=input_dir,
    annpath=input_json,
    categories=categories,
    super_categories=super_categories,
)

References

• VIA2COCO: the original repository
• VGG Image Annotator (VIA), by Oxford's Visual Geometry Group
• Common Objects in Context (COCO), by Microsoft
• An example of the VIA format, as shown in a Github issue