Image annotations

Guide for labeling image data.

Bounding box

Create a bounding box by starting at one corner and dragging your cursor to create the shape around an object in the image.

You can also click & drag to reposition the bounding box on the image.

See Bounding box for import/export details.

Segmentation mask

When you are labeling an image with the segmentation mask, you have a handful of tools that help you create segmentation annotations more efficiently.

See Segmentation mask for import/export details.

(Pro, Enterprise, and Education licenses only)

For Segmentation annotations with complex boundaries, using the Superpixel tool first may be more efficient than using the Pen tool alone. Superpixel works by calculating segment clusters of similarly colored pixels in the image.

In the top toolbar is a slider, which allows you to adjust the size of segment clusters from XS to XL. The easiest way to use Superpixel is to segment as much of the object as possible with Superpixel, then adjust the boundaries using the Pen and Eraser tools.

Calculation time for Superpixel segments increases with image size. We advise using images that are no more than 4000 by 4000 pixels.

Click the puzzle piece icon to use Superpixel.

Use the Superpixel tool to quickly label large areas.Use the Superpixel tool to quickly label large areas.

Use the Superpixel tool to quickly label large areas.

Pen tool

Use the Pen tool to outline the item in the image. Hold the cursor down to draw freehand or let the cursor go to draw straight lines between points. The Pen tool is only available when creating Segmentation annotations. Click the pen icon with the plus sign to use the pen tool.

Pen toolPen tool

Pen tool

Erase tool

You can use the Erase tool to clean up the edges of a segmentation mask. Click the pen icon with the minus sign to use the erase tool.

Erase toolErase tool

Erase tool

Fill tool

You can use the fill tool to easily label backgrounds or, otherwise, assign a segmentation annotation to all other pixels in the image that have not already been labeled. The fill tool is only enabled for Segmentation annotations.

Click the droplet icon to use the fill tool.


Create a Polygon annotation by clicking to create each point in the shape. Click the first point to close the Polygon.

See Polygon for import/export details.


Use the Polyline tool to label lines in an image. Click on the last point to complete the shape.

See Polyline for import/export details.


Use the point tool to label precise locations on the image.

See Point for import/export details.

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