The Labeling Interface

An overview of the Labeling Interface for Roboflow's Annotation Tool, including shortcut keys.

Written by Mohamed Traore

Last published at: June 7th, 2022

Be sure that you've uploaded a dataset before you get started: Dataset Upload: Roboflow Data Types

On the right-hand side of the labeling interface, you will find the Toolbar. It contains the following options:

Annotation Toolbar

  • Drag/Select(represented by a hand icon) allows you to select, edit, and drag individual annotations. 
    • Single-click an existing bounding box to select it. Once selected, you can change a bounding box's size with the circular white handles that appear on its corners and on each side. Or use the class editor to change the box's label.
    • Drag a box to move it.
    • Drag the background to pan.
    • Click the background to deselect all boxes.
  • Bounding Box(represented by a rectangular box icon) allows you to draw new bounding-box annotations. In this mode, you will see crosshairs that will help you determine where to start drawing. 
    • Click and drag across the image to create a new annotation, then use the Class Selector to choose its label.
  • Polygonallows you to draw new polygonal annotations. In this mode, you will see crosshairs that will help you determine where to start drawing. 
    • Click on the image around objects of interest to create an enclosed polygon annotation, then use the Class Selector to choose its label.
  • While in Bounding Box (B) or Polygon (P) mode:
    • Undo reverts the previous action.
    • Redo reverses a null undone action.

Undo and Redo

  • Repeat Previous reapplies label(s) on an image in the same location(s) as the last annotated image

Repeat Previous

When an image is selected, the Class Selector will appear. It contains the following options for choosing the label of a bounding box:

The Annotation Tool's Class SelectorThe Class Selector

  • Textfield to create a new class or filter existing classes.
  • Buttons to save or discard your changes.
  • Class List of the existing classes in the dataset (filtered by the text field and with the active option highlighted in purple) and, sometimes, a "Create class" option if the text you typed does not match an existing class.

At the bottom left of the screen, you will find the Zoom Tool. You can zoom in and out to fit more of the image on your screen at one time or to get a closer look for more detailed editing.

On the left-hand sidebar you will find the following drawers:

  • Annotations (abbreviated Annots) show which classes are present and not present in an image and what color their boxes are.
    • Watch this spot for updates soon as we add filtering and fine-tuning features.

Annotations (Annots) SidebarAnnotations (Annots) Sidebar

  • Attributes contains information about your image including its dimensions, last-modified time, and whether it is in this dataset's training, validation, or test set.

Attributes SidebarAttributes Sidebar

  • Raw Data is mostly used for debugging and can be safely ignored by most users unless our support team requests that you access it. It contains Roboflow internal representation of the image.

In the header you will find navigation to exit the labeling interface, move on to the next or previous image in the dataset, and perform the following actions:

  • View source image (represented by an eye with a slash through it) temporarily hides the bounding boxes to give you a closer look at the original image. 
  • Options(represented by an ellipsis) 
    • Use as Cover Photo marks the current image as the icon for the dataset on your homepage and uses it as the preview image for preprocessing and augmentation options.
    • Remove from Project removes the image from the project after confirmation.

Keyboard Shortcuts

The following keyboard shortcuts are available to speed up your labeling flow. The meta key is usually the command key on macOS and the ctrl key on Linux and Windows.

If no annotation is selected, the following keyboard shortcuts apply:

  • meta - temporarily switches between the Drag/Select and Bounding Box (B) or Polygon (P) tools while held down. (For example, if you are in Bounding Box mode, hold down the meta key and click an existing bounding box to select it.)
  • b - Switches to the Bounding Box tool.
  • p - Switches to the Polygon tool.
  • d - Switches to the Drag/Select tool. 
  • n - Switches to the Mark Nulltool. 
    • entering n while annotating an image that is already marked as Null will mark that image as Unannotated if it is currently in the Annotating queue.
  • plus - Zooms In.
  • minus - Zooms Out.
  • zero - Returns to Default Zoom (fits image into the viewport).
  • one - Zooms to 100%.
  • escape (esc) - Exits the Labeling Tool.
  • left arrow - Navigates to the previous image.
  • right arrow - Navigates to the next image.

Once an annotation is selected and the Class Selector is visible, the shortcuts are as follows:

  • enter - Saves the Active Option (highlighted in purple) as the current class, or label, for the selected bounding box.
  • escape (esc) - Cancels and deselects the current box without changing its label (if the currently selected box was just drawn it will be deleted).
  • up arrow - Changes the Active Option (class/label) to the previous one.
  • down arrow - Changes the Active Option (class/label) to the next one.
  • backspace - Deletes the current bounding box if there is no text in the text field (this means you will usually have to push backspace twice to delete a box after selecting it; one time to delete the highlighted text and a second time to confirm deletion).