Importing Brush Traces

You may import PNG masks as pre-labels for the Brush labeling tool in Ango Hub.

How to Import Masks as Brush Annotations

1. In your project, navigate to Settings, and then to Category Schema. Ensure your project has the Brush tool classes you intend to import.

2. For each Brush tool in your project, take note of its hexadecimal color value. You can do so by pressing on the Show JSON button on the right.

For example, in the following project, I have a single Brush labeling tool, and its hex color value is #f44336.

3. Prepare the PNG masks you intend to import. The PNG masks need to:

   1. Have the same dimension as the image asset to annotate

   2. Have a completely transparent background (255, 255, 255, 0)

   3. Have the mask contents' colors be the same as the colors of the brush tools in your project on Hub. The masks need to be fully opaque (e.g. alpha channel value 0) and never have colors outside of the ones determined in step 2.

Ensure that the masks you are importing have the same color value as the brush tool you wish to associate the mask with as per step 2.

In the same PNG mask you may import traces for more than one brush class, as long as the color of each trace matches the color of each class on Hub.

Assuming you had one brush class on Hub with the hex color value f44336, the following would be a valid PNG mask:

6KB

brush-import-docs.png

image

4. Prepare the JSON to import to Hub, in the following format:

[
  {
    "externalId": "0a6e52c9-1eda-426f-8bcb-e6b1cd45668c.png",
    "brushDataUrl": "https://domain.s3.eu-central-1.amazonaws.com/brush-import-samples/0a6e52c9-1eda-426f-8bcb-e6b1cd45668c.png"
  },
  {
    "externalId": "0e9ee946-ebaa-4847-99ee-ce7386795333.png",
    "brushDataUrl": "https://domain.s3.eu-central-1.amazonaws.com/brush-import-samples/0e9ee946-ebaa-4847-99ee-ce7386795333.png"
  },
  {
    "externalId": "0eaf2333-5533-4353-ac3d-55774b6adb47.png",
    "brushDataUrl": "https://domain.s3.eu-central-1.amazonaws.com/brush-import-samples/0eaf2333-5533-4353-ac3d-55774b6adb47.png"
  },
  {
    "externalId": "0ebf0551-6c2d-4b6e-9a46-d5e1a5f22e72.png",
    "brushDataUrl": "https://domain.s3.eu-central-1.amazonaws.com/brush-import-samples/0ebf0551-6c2d-4b6e-9a46-d5e1a5f22e72.png"
  },
  {
    "externalId": "0f6d11a6-4fb0-4973-a8a3-d702de764548.png",
    "brushDataUrl": "https://domain.s3.eu-central-1.amazonaws.com/brush-import-samples/0f6d11a6-4fb0-4973-a8a3-d702de764548.png"
  }
]

Where externalId is the external ID of the asset to pre-annotate, and brushDataUrl is a link to your publicly-accessible PNG mask.

If your masks are stored in a cloud storage service, ensure the bucket's CORS settings are set properly, or your masks will not be visible on Hub.

Here is a guide on how to set up CORS in such a way that your masks will be visible.

5. In your project, navigate to the Assets tab, then click on Import. Drag and drop the JSON file you have just prepared. Your assets will be pre-labeled.