2D Polygon

Overview: The Polygon tool is used to create geometric annotations by drawing lines between points.

Steps to Draw a Polygon

  1. Click on Label type and select Polygon from the top left menu of the editor.

2. Select a category from the drop-down box.

3. Draw a polygon, keeping points on the image with a left mouse click. You can label the same polygon ID by holding an “Alt” key for the first polygon point or by selecting a label and clicking on Draw selected polygon. Then continue the polygon labeling for the object with the same ID.

4. You can select the label by clicking on the label with a left mouse click. Double-click on a polygon to edit it by dragging the highlighted points of the line with a left mouse click and also you can delete the selected highlighted point by pressing the “Delete” key. To add a point on the line, click on the line using the left mouse click.

5. You can draw another line by pressing the “Esc” key twice. 6.Labels are saved automatically. 7. Users can submit their work by clicking on the submit button at the bottom. Refer to Task Life Cycle for more information.

Polygon (Foreground/Background): Knowing how to use the foreground and background can come in handy in data labelling for polygons. If there is an object at the back of another object, that is when this feature comes into play. Draw a polygon as Foreground:

1. Selecting a foreground option from the image editor page

2. For example, if you want to label a “Car” in the below image without interrupting the “Building” polygon, you want to select a Foreground option before saving the “Car” label as the Building is the Background and car is the foreground object.

3. If you use Background instead of Foreground option, it will not be cut by the Background polygon label(Building).

Draw a polygon as Background:

  1. Selecting a Background option from the image editor page.

2. For example, if you want to label a building in the below image without interrupting the car polygon, you want to select a background option before saving the building label because the Building is the Background and the car is the foreground object.

3. When you label a background object with a background option, it will get a polygon accurately to the object without disturbing the foreground label (Car). 4. If you use the foreground instead of the background option, it will interrupt the foreground polygon label (Car).