Work on Video Frame Object Detection Tasks - Amazon SageMaker

Work on Video Frame Object Detection Tasks

Video frame object detection tasks required you to classify and identify the location of objects in video frames. A video frame is a still image from a video scene.

You can use the worker UI to navigate between video frames and draw labeled bounding boxes around objects. Use the sections on this page to learn how to navigate your worker UI, use the tools provided, and complete your task.

It is recommended that you complete your task using a Google Chrome web browser.

Your Task

When you work on a video frame object detection task, you need to select a category from the Label category menu on the right side of your worker portal to start annotating. After you've chosen a category, draw boxes around objects that this category applies to. Adjust boxes so they fit tightly around object boundaries. After you place a box, you can modify its dimensions and location.

After you've added a label, you may see a downward pointing arrow next to the label in the Label ID menu. Select this arrow and then select one option for each label attribute you see to provide more information about that label.

To edit a box, including moving and changing box dimensions, select the label of the box that you want to edit in the Label ID menu or select the box in the frame. When you edit or delete a box, the action will only modify the box in a single frame.

To change the box dimensions, use your mouse to select one of the dots around that box and drag to stretch or shrink the box.

To move the box, select the box in the image and drag the box to the desired location.

To delete a box, use the Delete key on your keyboard, or the trash can icon by the label in the Labels menu.

Use the predict next icon to predict the location of all bounding boxes that you have drawn in a frame in the next frame. If you select a single box and then select the predict next icon, only that box will be predicted in the next frame. If you have not added any boxes to the current frame, you will receive an error. You must add at least one box to the frame before using this feature.

Note

The predict next feature will not overwrite your annotations. It will only add annotations. If you use predict next and as a result have more than one bounding box around a single object, delete all but one box. Each object should only be identified with a single box.

After you've used the predict next icon, review the location of each box in the next frame and make adjustments to the box location and size if necessary.

If you see boxes have already been added to one or more video frames when you open your task, adjust those boxes and add additional boxes as needed.

Navigate the UI

You can navigate between video frames using the navigation bar in the bottom-left corner of your UI.

Use the play button to automatically play through multiple frames.

Use the next frame and previous frame buttons to move forward or back one frame at a time. You can also input a frame number to navigate to that frame.

The following video demonstrates how to navigate between video frames.

You can zoom in to and out of all video frames. Once you have zoomed into a video frame, you can move around in that frame using the move icon. When you navigate to a new view in a single video frame by zooming and moving within that frame, all video frames are set to the same view. You can reset all video frames to their original view using the fit screen icon. To learn more, see Icon Guide.

When you are in the worker UI, you see the following menus:

  • Instructions – Review these instructions before starting your task. Additionally, select More instructions and review these instructions.

  • Shortcuts – Use this menu to view keyboard shortcuts that you can use to navigate video frames and use the annotation tools provided.

  • Help – Use this option to refer back to this documentation.

Icon Guide

Use this table to learn about the icons you see in your worker task portal. You can automatically select these icons using the keyboard shortcuts found in the Shortcuts menu.

Icon Description

add bounding box

Choose this icon to add a bounding box. Each bounding box you add is associated with the category you choose from the Label category drop down menu.

predict next

Select a bounding box, and then choose this icon to predict the location of that box in the next frame. You can select the icon multiple times in a row to automatically detect the location of box in multiple frames. For example, select this icon 5 times to predict the location of a bounding box in the next 5 frames.

brightness

Choose this icon to adjust the brightness of all video frames.

contrast

Choose this icon to adjust the contrast of all video frames.

zoom in

Choose this icon to zoom into all of the video frames.

zoom out

Choose this icon to zoom out of all of the video frames.

move screen

After you've zoomed into a video frame, choose this icon to move around in that video frame. You can move around in the video frame using your mouse by clicking and dragging the frame in the direction you want it to move. This will change the view in all view frames.

fit screen

Reset all video frames to their original position.

undo

Undo an action. You can use this icon to remove a bounding box that you just added, or to undo an adjustment you made to a bounding box.

redo Redo an action that was undone using the undo icon.
delete label Delete a label. This will delete the bounding box associated with the label in a single frame.
show or hide label Select this icon to show a label that has been hidden. If this icon has a slash throguh it, select it to hide the label.

Shortcuts

The keyboard shortcuts listed in the Shortcuts menu can help you quickly select icons, undo and redo annotations, and use tools to add and edit bounding boxes. For example, once you add a bounding box, you can use P to quickly predict the location of that box in subsequent frames.

Before you start your task, it is recommended that you review the Shortcuts menu and become acquainted with these commands.

Saving Your Work and Submitting

You should periodically save your work. Ground Truth automatically saves your work every 15 minutes.

When you open a task, you must complete your work before pressing Submit. If you select Stop Working,you lose that task, and other workers can start working on it.