Creating annotations

In general¶

You can answer an annotation question by clicking the relevant Edit annotation button, this will open the annotation editor. It will also trigger a yellow highlight around the image that should be used to create the annotation. For most annotation types you can create an annotation with a left-click and drag action, point annotations require only a left-click. You can close the editor with either the Finish annotation button or with a right-click on the highlighted image.

When a question is of a single annotation type, there will only be a single annotation allowed as answer. If you create a second annotation for such a question, the first annotation will be removed.

⚠️ All annotations need to be closed to be able to save them.

Polygon annotation editor¶

Interaction mode¶

The polygon annotation editor has four interaction modes:

1. Brush: Allows you to draw a shape as if using a brush. Hold Alt + scroll to change brush size.

2. Freehand: Allows you to draw a shape as if using a pencil. To close the annotation, let go of the mouse button when the cursor changes to a linking icon while close to the beginning of the annotation. If you do not close the annotation, it will be added to the nearest annotation.

3. Spline: Allows you to create a spline by left-clicking subsequently to place coordinates. Finish the annotation by left-clicking when the cursor changes to a linking icon while close to the beginning of the annotation.

4. LiveWire: Allows you to follow certain contours in the image by left-clicking subsequently along the contours. The wire will try to snap to edges automatically. Finish the annotation by left-clicking when the cursor changes to a linking icon while close to the beginning of the annotation.

Linking cursor:

Edit mode¶

The polygon editor starts default on edit mode Auto. This means that on the first interaction, a polygon annotation will be created. After that, the location of the cursor determines the mode. If the cursor is outside of the first annotation the mode is set to Remove, made visible by the minus sign next to the cursor. If the cursor is inside of the first annotation, the mode is set to Add, made visible by the plus sign next to the cursor.

Cursor in mode Add: .
Cursor in mode Remove: .

If you want more control over which mode you want to be in, you can switch by selecting Add or Remove, or by using the Shift key.

Delete a polygon annotation¶

It is possible to delete a single polygon annotation, which might be useful in a multiple polygon type question and other polygons needs to be retained. To delete a single polygon, check the "Make selectable" option in the editor, then select the annotation you would like to delete and click Delete.

⚠️ Make sure to unselect the "Make selectable" option when you are done deleting, otherwise you will not be able to create new annotations.

💡To delete all annotations for a single question it's easier to this outside of the editor: Finish annotation > Delete annotation button should be present for the question.

Switching orientation¶

When editing a 3D volume, you can switch orientation during the creation of a polygon annotation. The created annotation will be projected onto the new viewing plane each time you switch. This allows editing of the polygons in all directions.

⚠️ When you are finished and click "Save annotation", the currently visible polygons will be saved. So make sure you are in the correct orientation when saving.

Mask annotation editor¶

Interaction mode¶

The mask editor does not have an Auto mode, you can switch between Add and Remove by selecting the different modes or by holding down the Shift key. Similar to the polygon editor you can change the brush size by holding down Alt + scroll.

Switching between Mask and Polygon Editor¶

While creating mask or polygon annotations, you can switch between the different editors by using the Switch to.. button. A polygon transforms into a mask and vice versa. This allows you to use the extended functionalities of the polygon tool such as snapping and tool selection, while still creating an (editable) mask.

⚠️ Finishing the annotation requires you to be at the correct annotation type.