Labeling tool

Labeling tool

SentiSight labeling tool offers a variety of instruments to add object labels to an image, allowing you to precisely define which parts of an image contain what objects.

Object labels are different from classification labels and are used for object detection and segmentation model training (available as custom projects only). Images that have been labeled with object labels are marked with this symbol.
Object labels made count towards "Labels made" statistic and appear in the list of project's labels. "Synchronise labels" setting also makes it so object labels added also label the image for classification with same label. Below you can see basic types of object labels you can use in the labeling tool.
Bounding boxes are simple rectangular shapes. You can set fixed aspect ratio for bounding boxes in the settings. ”Image
Polygons are complex shapes defined by multiple points connected by lines. Holes are WIP. A single object can consist of multiple polygons and/or holes. ”Image
Polylines are collections of points connected by lines, useful for labeling things which are defined by structure, not precise shape. ”Image
Points are useful for labeling miniscule objects. ”Image
Bitmaps are freeform hand-drawn masks that can be used to label objects that have complex shapes. Note that at this point you cannot directly upload bitmaps the way you can upload other object types. ”Image

Shared features

The following features are applicable to most object types.
Attributes are text-only notes that can be added to objects. They are currently not used in any form of model training.

Keypoints can be added to bounding box and polygon objects, marking position of important points - e.g. eyes and nose on a face.


Bounding boxes and polygons can be converted to bitmap masks using Rasterize button. Additionally Rasterize All Objects button is present to turn all applicable objects into bitmaps.

Please note that rasterization clears all keypoints and attributes from the object.

Converting bitmap to polygon

Additionally, bitmaps can be converted to polygons using Convert to polygon button.

You can choose to convert a bitmap to very detailed polygon perfectly resembling it or use "Simplify polygons converted from bitmap" setting to create a much simpler polygon.

Smart selection tool

Smart selection tool is a powerful instrument that allows you to quickly create complex bitmap masks by detecting objects on background.

All it needs is a user to show it where foreground and background are, at which point it checks whether pixels belong to one or another.

Using smart selection tool

1. Select a rectangular area that the tool will work in.

2. Mark the foreground. For largely homogenous looking regions that contrast well with the background a few brief lines is enough. For regions with complex colors that may blend with the background it might be better

3. Mark the background. In general you don't have to be very precise.

4. Press Extract to have the tool mask the foreground. Examine it carefully to make sure it covers all parts of the image you want.

5. Repeat steps 2-4 until you are content.

6. Once you are content with the result, press Done to produce a bitmap mask. You can touch it up with Bitmap tool if you need.

Please note that until you press Done the work done with smart selection tool cannot be saved and will be lost if you click on another tool, switch image, or close labeling tool.

You can see workflow of smart selection tool in the gif below.