Bounding Box

Overview of the Bounding Box labeling tool in Ango Hub

The bounding box labeling tool allows you to draw a box around an object or point of interest in an image. It also allows you to perform OCR on the area marked by the box.

How to add a Bounding Box tool to your project

From the project’s Settings tab, enter the Label Set section.

Click on Add Category. From the list that appears, click on Bounding Box.

A new row will appear named Bounding Box. Click on it to expand it.

Schema ID: A unique ID which identifies this class in your project.

Title: The name of your class.

Required: Whether or not annotators have to add at least one instance of this class in order to submit their annotation task.

Targeted OCR: By enabling this, you will be able to perform OCR and get the OCR results in the exports for the areas highlighted by the bounding boxes belonging to this class.

By default, targeted OCR only detects English. To change, add, or remove which languages should be detected in your project, head over to Settings -> Quality to do so:

If you would like to ask labelers further questions, for example, if you want to show a further radio after drawing the bounding box, click on Add Classification and add a further question. More on nested questions here.

How to Draw a Bounding Box

Click on the image where you’d like the bounding box to start. Click again where you’d like the bounding box to end.

After creating the box, you can change its size by selecting it by clicking it, then dragging on its points. You can drag the entire bounding box by selecting it then dragging it with the mouse cursor.

Perform OCR on the contents of the bounding box

Hub allows you to perform OCR on the contents of bounding boxes, both single and in bulk.

To do so, when adding your bounding box class to your project, enable the Targeted OCR toggle as mentioned in this section.

On a Single Bounding Box

Once you are in the labeling editor, draw a bounding box over the text you'd like to perform OCR on. Then, right-click on the box and expand the context menu. This is what you should see:

On Multiple Bounding Boxes

In the labeling editor, press Shift and click on the bounding boxes you'd like to perform OCR on. Once you have selected all boxes, right click on any one of them and click on Run OCR.

To see the OCR results, right-click on a box and expand the context menu that appears. Alternatively, expand the rows in the Objects section in the lower-left corner of the UI.

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