Label and annotate data

Label and annotate your data with the open source data labeling tool, Label Studio. After you set up your project and labeling interface and import your data, you can start labeling and annotating your data.

1. Open a project in Label Studio and optionally filter or sort the data.
2. Click Label All Tasks to start labeling.
3. Use keyboard shortcuts or your mouse to label the data and submit your annotations.
4. Follow the project instructions for labeling and deciding whether to skip tasks.
5. Click the project name to return to the data manager.

You can also collaborate with other annotators to improve the quality of your labeled data.

Filter or sort project data

When you filter or sort the data before you label it, you modify which tasks and the order of the tasks you see when labeling. While task sampling affects the task order for an entire project and can’t be changed, filtering and sorting tasks can be changed at any time.

Example: Label new data first

Sort the data in your project by date to focus on labeling the newest data first.

1. In a project, update the Order of the data from the default to Created at.
2. Update the order of the items to be in ascending order, so the newest items appear first.
3. Select Label Tasks As Displayed to start labeling tasks from newest to oldest.

Example: Sort by prediction score

You can sort the data in your project by prediction score if you upload pre-annotated data with prediction scores, or if your machine learning backend produces prediction scores as part of the model output.

1. In a project, update the Order of the data from the default to use the Prediction score field.
2. Update the order of the items in either ascending or descending order to label based on higher confidence or lower confidence predictions.
3. Select Label Tasks As Displayed to start labeling tasks in prediction score order.
   You can also use task sampling to use prediction score ordering.

Example: Split a dataset using tabs and filters

If you want to label a large dataset, you might want to use tabs and filters to split it up into smaller sections, and assign different annotators to different tabs. You can’t assign annotators to specific tasks in Label Studio Community Edition, but you can rename the tabs after specific annotators as a way to basically assign tasks using tabs.

For example, you might split a dataset with 300 images into 3 different tabs, and have different annotators focus on each tab:

1. In a project, create a filter where the ID field is between the values “1” and “100”. Click away from the filter to review filtered items the tab.
2. Click the vertical ellipsis for the tab and select Rename. Name it after a specific annotator that you want to focus on the items in that tab.
3. Click the + icon to create a new tab. Click the vertical ellipsis for the new tab and select Rename to name it after a second annotator.
4. On the new tab, create a filter where the ID field is between the values “101” and “200”. Click away from the filter to review the filtered items on the tab.
5. Click the + icon to create a new tab. Click the vertical ellipsis for the new tab and select Rename to name it after a third annotator.
6. On the new tab, create a filter where the ID field is between the values “201” and “300”. Click away from the filter to review the filtered items on the tab.
7. Any annotator can log in and navigate to the relevant tab for their work and click the Label button to start labeling the subset of tasks on their tab.

Start labeling

Some labeling tasks can be complicated to perform, for example, labeling that includes text, image, and audio data objects as part of one dataset and labeling task, or creating relations between annotations on a labeling task. This section includes guidance on how to perform more complex labeling tasks, such as labeling with relations, overlapping regions, selected tasks, or changing labels.

Choose which tasks to label

From a project, click Label All Tasks to start labeling all tasks. To label the tasks as they are filtered and sorted in the data manager, select Label Tasks As Displayed instead.

You can also label a specific task in the Quick View or Preview by clicking it from the project data manager view, but you won’t automatically see the next task in the labeling queue after submitting your annotations.

You can also select the checkboxes next to specific tasks and then click Label $n Tasks to label the selected number of tasks. For example, select the checkboxes for 5 different tasks, then click Label 5 Tasks to label only those 5 tasks.

Label a region in the data

Annotate a section of the data by adding a region.

1. Select the label you want to apply to the region. For some configurations, you can skip this step.
2. Click the text, image, audio, or other data object to apply the label to the region. Your changes save automatically.
3. Click Submit to submit the completed annotation and move on to the next task.

Label overlapping regions

When you label with bounding boxes and other image segmentation tasks, or when you’re highlighting text for NLP and NER labeling, you might want to label overlapping regions. To do this easily, hide labeled regions after you annotate them.

1. Select the label that you want to apply to the region.
2. Draw the bounding box or highlight the text that you want to label.
3. In the Regions or Labels sidebar, locate and select the region that you labeled and click the eye icon to hide the region.
4. Select the next label that you want to apply to the overlapping region.
5. Draw the bounding box or highlight the text that you want to label.
6. Continue hiding and labeling regions until you’ve completed annotating the task. If you want, select the eye icon next to Regions to hide and then show all regions labeled on the task to confirm the end result.
7. Click Submit to submit the completed annotation and move on to the next task.

Select multiple regions

You can select multiple regions while labeling to make changes to them together.

1. After creating multiple regions, press ctrl and click each region that you want to select. You can select regions on the object that you’re labeling or in the Regions sidebar. Select a range of regions in the Regions sidebar by clicking the first region in the list that you want to select and holding Shift while you click the last region in the list that you want to select.
2. After selecting the regions you can apply a label to all selected regions or delete them.
3. Click a selected region or press u to deselect it.

Duplicate regions

You can duplicate a region to create many identically-sized polygons, rectangles, or ellipses.

1. Select the region that you want to duplicate.
2. Press ctrl + d to duplicate the region, or the sequence of ctrl + c and ctrl + v to copy and paste the region. Duplicated regions appear in the exact location as the region being duplicated. If you’re using a Mac keyboard, use cmd instead of ctrl.
3. Click the arrow tool, then move and resize the newly-created region.

Change the label

You can change the label of an existing region.

1. Select the labeled region, for example a span, bounding box, image segment, audio region, or other region, on the object or using the Regions sidebar.
2. Select a new label. Your changes to the label save automatically.
3. Click Submit to submit the completed annotation and move on to the next task.

Delete a labeled region

You can delete labeled regions, such as bounding boxes or text spans, if needed.

1. Select the labeled region on the object or in the Regions sidebar.
2. Press the Backspace key, or go to the Results panel and remove the selected annotation.

Delete an annotation

After labeling a task, you can delete the annotation by clicking the trash can button to delete an annotation on the task. If you haven’t saved your annotation yet, click the X icon to reset the task and remove your labeling activity.

You can also delete all annotations on a task from the project page. See Delete tasks or annotations.

Add relations between annotations

You can create relations between two results with both directions and labels. To add labels to directions, you must set up a labeling config with the relations tag. See more about relations with labels in the Tags documentation.

1. Select the region for the annotation that you want to relate to another annotation. If you’re creating a direction-based relation, select the first one first.
2. In the Regions section of the Results sidebar, click the Create Relation button that looks like a hyperlink icon.
3. Select the second region for the annotation to complete the relation.

After you relate two annotation regions, you can modify the relation in the Relations section of the Results sidebar.

• To change the direction of the relation, click the direction button between the two related regions.
• To add labels to the direction arrow indicating the relation between two annotations, click the vertical ellipsis button next to the two related regions to add your predefined labels. You must have a label configuration that includes relations to do this.

Skipping a task

When annotators skip a task, the task no longer appears in the labeling queue for that annotator. Other annotators still see the task in their labeling queue.

Label with collaborators

In both Label Studio and Label Studio Enterprise, you can label tasks with collaborators. Tasks are locked while someone performs annotations so that you don’t accidentally overwrite the annotations of another annotator. After the other annotator finishes with the task, it can appear in your queue for labeling if the minimum annotations per task is set to more than one. By default, tasks only need to be annotated by one annotator.

If you want to label tasks more than once, even if the minimum annotations required is set to one, do the following:

To label tasks multiple times while the minimum annotations required is set to one, do the following:

1. In the data manager for the project, click a task to open the quick labeling view.
2. Click the + icon next to the task annotation ID to open an annotation tab.
3. Label the task.
4. Click Submit to save your annotation.
5. Click the next task in the data manager to open the quick labeling view for that task and repeat steps 2-4.

Assign annotators to tasks

In Label Studio Enterprise, if you’re an administrator or project manager, you can assign annotators to tasks in a specific project. After you add the annotator to the project or workspace, assign the annotator to specific tasks.

1. For a specific project, select tasks on the Data Manager.
2. Select the dropdown and choose Assign Annotators.
3. Select names of annotators and click the > arrow to assign them to the selected tasks.
4. Click Assign.

Perform ML-assisted labeling with interactive preannotations

If you have a machine learning backend set up to get interactive preannotations, you can choose whether to use those predictions while you label.

1. After you start labeling, you can enable Auto-Annotation to see and use the smart option to assign a label to draw a shape, mask, or assign a keypoint. After using the smart option to draw on an image, or labeling a text or HTML span, the ML backend returns predictions.
2. For image labeling, you can choose whether to Auto accept annotation suggestions after you enable auto-annotation. If you automatically accept annotation suggestions, regions show up automatically and are immediately created. If you don’t automatically accept suggestions, the regions appear but you can reject or approve them manually, either individually or all at once. Predicted text regions are automatically accepted.

Use keyboard shortcuts to label regions faster

Use keyboard shortcuts, or hotkeys, to improve your labeling performance. When performing a labeling task, click the gear icon to see more details about hotkeys or to enable or disable hotkeys.

This table describes the hotkeys for a standard keyboard. For a Mac keyboard, use return instead of enter, delete instead of backspace, and option instead of alt.

Key	Description
ctrl + enter	Submit a task.
alt + enter	Update a task.
ctrl + backspace OR cmd + backspace	Delete all regions.
escape	Exit relation mode or unselect a selected region.
backspace	Delete a selected region.
alt + r	Create a relation between regions, when a region is selected.
alt + .	Cycle through all regions in the order listed on the regions sidebar.
alt + h	Hide a selected region.
ctrl + d OR cmd + d	Duplicate a selected region.
u	Unselect a selected region.
s	On the data manager, change the row selection to the next row, 1 below the current row.
w	On the data manager, change the row selection to the previous row, 1 above the current row.
d	On the data manager, open the labeling quick view for the selected task row.
a	On the data manager, close the labeling quick view for the selected task row.

Other annotation types have labeling-specific shortcuts, such as numbers to select specific labels for named entity recognition tasks.

Image-specific hotkeys

When labeling image data types with the Rectangle, BrushLabels, Ellipse, Polygon, or KeyPoints tags, you can use specific hotkeys to take image labeling-specific actions.

Key	Description
h	Pan the image, after zooming in.
v	Select the mouse arrow.
alt + left arrow	Rotate the image to the left.
alt + right arrow	Rotate the image to the right.
ctrl + +	Zoom in to the image.
ctrl + -	Zoom out of the image.
k	If performing key point labeling, select the key point option in the toolbar.
e	Select the eraser option in the toolbar.
b	If performing brush mask labeling, select the brush option in the toolbar.
[	When the brush or eraser option is selected, decrease the size of the brush or eraser.
]	When the brush or eraser option is selected, increase the size of the brush or eraser.

Audio-specific hotkeys

When labeling audio data types with the Audio or AudioPlus tags, you can use specific hotkeys to take audio-specific actions.

Key	Description
ctrl + b OR cmd + b	Rewind audio 1 second.

Time series-specific hotkeys

When labeling timeseries data with the TimeSeries tag, you can use specific hotkeys to take actions on a selected region on the time series data.

Key	Description
left arrow	Expand the region area to the left.
right arrow	Expand the region area to the right.
alt + left arrow	Decrease the region area on the left.
alt + right arrow	Decrease the region area on the right.
shift + left arrow	Expand the region area by a larger amount to the left.
shift + right arrow	Expand the region area by a larger amount to the right.
shift + alt + left arrow	Decrease the region area by a larger amount on the left.
shift + alt + right arrow	Decrease the region area by a larger amount on the right.

Video-specific hotkeys

When labeling video data with the Video tag, you can use specific hotkeys to take video-specific actions.

Key	Description
alt + spacebar	Play or pause video.
alt + left arrow	Rewind one frame.
alt + right arrow	Fast forward one frame.

Customize hotkeys

You can specify custom hotkeys for labeling using the Shortcut tag, or change the hotkeys used for specific actions using an environment variable.

If you want to change the hotkeys used for specific actions, set the EDITOR_KEYMAP environment variable with valid JSON in your .env file or when starting Label Studio. For example, to change the keyboard shortcut used to submit an annotation to shift + s, set the environment variable as follows:

EDITOR_KEYMAP='{"annotation:submit":{"key": "shift+s","description": "My Custom Submit Hotkey!"}}'

This overwrites the existing hotkey mapping with your custom mapping. See more about how to set environment variables.

Refer to the full list of customizable hotkeys in the keymap.json file of the label-studio-frontend repository to update a different hotkey combination.

You cannot use this environment variable to remove an existing or add a new keyboard shortcut.

Customize the labeling interface

Click the settings icon when labeling to configure the labeling interface to suit your labeling use case.

For example, keep a label selected after creating a region, display labels on bounding boxes, polygons and other regions while labeling, and show line numbers for text labeling.

You can also modify the layout of the screen, hide or show predictions, annotations, or the results panel, and hide or show various controls and buttons.

Advanced image labeling

If you want to perform advanced image labeling, follow these examples and guidance for assistance.

Add multiple types of regions to image annotations

You can add multiple types of regions to image annotations. You can add any of the following:

• Rectangles
• Ellipses
• Keypoints
• Polygons
• Brush masks

To add different types of regions to your image annotations, follow this example.

Create a custom template for your labeling interface using the following example:

<View>
  <Image name="image" value="$image" />
  <Rectangle name="rect" toName="image" />
  <Ellipse name="ellipse" toName="image" />
  <KeyPoint name="kp" toName="image" />
  <Polygon name="polygon" toName="image" />
  <Brush name="brush" toName="image" />
  <Choices name="choices" toName="image">
    <Choice value="yes"></Choice>
    <Choice value="no"></Choice>
  </Choices>
<Labels name="labels" toName="image" fillOpacity="0.5" strokeWidth="5">
  <Label value="building" background="green"></Label>
  <Label value="vehicle" background="blue"></Label>
  </Labels>
</View>

This example makes rectangles, ellipses, polygons, keypoints, and brush masks available to the annotator, along with image classification choices of yes and no, and region labels of building and vehicle.

Faster image labeling

You can add a rectangle or an ellipse to your image with just two clicks, or double click to create a polygon, rectangle, or ellipse.

If you accidentally select a point on an image while creating a polygon, just double click to remove the erroneous point and continue creating the region. There must be at least three points on the polygon to be able to remove a point.

Create regions without labels

When you’re annotating images, you can create regions without applying labels.

1. Create a region by double-clicking or clicking and dragging to create a bounding box, or click the points necessary to construct a polygon.
2. Select the created region in the sidebar or on the image.
3. Select the label that you want to apply to the region.
4. Repeat these steps for any regions that you want to create.

This can be helpful for two-step labeling, where you want one annotator to create regions and another annotator to label the regions.

By default, regions without labels appear gray.

Erase brush mask labels

If you make a mistake when labeling with the brush mask, you can erase it. You must select a brush region in the sidebar before you can erase any part of it.

If you want to completely remove a region and start over, delete the region instead of erasing it. Erasing a region does not delete it.

How Label Studio saves results in annotations

Each annotation that you create when you label a task contains regions and results.

• Regions refer to the selected area of the data, whether a text span, image area, audio segment, or something else.
• Results refer to the labels assigned to the region.

Each region has a unique ID for each annotation, formed as a string with the characters A-Za-z0-9_-. Each result ID is the same as the region ID that it applies to.

When a prediction is used to create an annotation, the result IDs stay the same in the annotation field. This lets you track the regions generated by your machine learning model and compare them directly to the human-created and reviewed annotations.