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 using annotations. A video frame is a still image from a video scene.

You can use the worker UI to navigate between video frames and create annotations to identify objects of interest. 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.

Important

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

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 annotations around objects that this category applies to. To learn more about the tools you see in your worker UI, refer to the Tool Guide.

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

You may see frame attributes under the Labels menu. These attributes will appear on each frame in your task. Use these attribute prompts to enter additional information about each frame.

To edit an annotation, select the label of the annotation that you want to edit in the Labels menu or select the annotation in the frame. When you edit or delete an annotation, the action will only modify the annotation in a single frame.

If you are working on a task that includes a bounding box tool, 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 manually created 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.

The following graphic demonstrates how to use the predict next tool:

For all other tools, you can use the Copy to next and Copy to all tools to copy your annotations to the next or all frames respectively.

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 UI 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.

If you

Bulk Edit Label and Frame Attributes

You can bulk edit label attributes and frame attributes (attributes).

When you bulk edit an attribute, you specify one or more ranges of frames that you want to apply the edit to. The attribute you select is edited in all frames in that range, including the start and end frames you specify. When you bulk edit label attributes, the range you specify must contain the label that the label attribute is attached to. If you specify frames that do not contain this label, you will receive an error.

To bulk edit an attribute you must specify the desired value for the attribute first. For example, if you want to change an attribute from Yes to No, you must select No, and then perform the bulk edit.

You can also specify a new value for an attribute that has not been filled in and then use the bulk edit feature to fill in that value in multiple frames. To do this, select the desired value for the attribute and complete the following procedure.

To bulk edit a label or attribute:

1. Use your mouse to right click the attribute you want to bulk edit.

2. Specify the range of frames you want to apply the bulk edit to using a dash (-) in the text box. For example, if you want to apply the edit to frames one through ten, enter 1-10. If you want to apply the edit to frames two to five, eight to ten and twenty enter 2-5,8-10,20.

3. Select Confirm.

If you get an error message, verify that you entered a valid range and that the label associated with the label attribute you are editing (if applicable) exists in all frames specified.

You can quickly add a label to all previous or subsequent frames using the Duplicate to previous frames and Duplicate to next frames options in the Label menu at the top of your screen.

Tool Guide

Your task will include one or more tools. The tool provided dictates the type of annotations you will create to identify and label objects. Use the following table to learn more about the tool or tools you may see in your worker UI.

Tool	Icon	Action	Description
Bounding box		Add a bounding box annotation.	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. Select the bounding box or its associated label to adjust it.
Predict next		Predict bounding boxes in the next frame.	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.
Keypoint		Add a keypoint annotation.	Choose this icon to add a keypoint. Click on an object the image to place the keypoint at that location. Each keypoint you add is associated with the category you choose from the Label category drop down menu. Select a keypoint or its associated label to adjust it.
Polyline		Add a polyline annotation.	Choose this icon to add a polyline. To add a polyline, continuously click around the object of interest to add new points. To stop drawing a polyline, select the last point that you placed a second time (this point will be green), or press Enter on your keyboard. Each point added to the polyline is connected to the previous point by a line. The polyline does not have to be closed (the start point and end point do not have to be the same) and there are no restrictions on the angles formed between lines. Each polyline you add is associated with the category you choose from the Label category drop down menu. Select the polyline or its associated label to adjust it.
Polygon		Add a polygon annotation.	Choose this icon to add a polygon. To add a polygon, continuously click around the object of interest to add new points. To stop drawing the polygon, select the start point (this point will be green). A polygon is a closed shape defined by a series of points that you place. Each point added to the polygon is connected to the previous point by a line and there are no restrictions on the angles formed between lines. Two lines (sides) of the polygon cannot cross. A line will become red if it violates this condition. The start and end point must be the same. Each polygon you add is associated with the category you choose from the Label category drop down menu. Select the polygon or its associated label to adjust it.
Copy to Next		Copy annotations to the next frame.	If one or more annotations are selected in the current frame, those annotations are copied to the next frame. If no annotations are selected, all annotations in the current frame will be copied to the next frame.
Copy to All		Copy annotations to all subsequent frames.	If one or more annotations are selected in the current frame, those annotations are copied to all subsequent frames. If no annotations are selected, all annotations in the current frame will be copied to all subsequent frames.

UI 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
	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 through 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 annotations. 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.

Release, Stop and Resume, and Decline Tasks

When you open the labeling task, three buttons on the top right allow you to decline the task (Decline task), release it (Release task), and stop and resume it at a later time (Stop and resume later). The following list describes what happens when you select one of these options:

• Decline task: You should only decline a task if something is wrong with the task, such as unclear video frame images or an issue with the UI. If you decline a task, you will not be able to return to the task.

• Release Task: Use this option to release a task and allow others to work on it. When you release a task, you loose all work done on that task and other workers on your team can pick it up. If enough workers pick up the task, you may not be able to return to it. When you select this button and then select Confirm, you are returned to the worker portal. If the task is still available, its status will be Available. If other workers pick it up, it will disappear from your portal.

• Stop and resume later: You can use the Stop and resume later button to stop working and return to the task at a later time. You should use the Save button to save your work before you select Stop and resume later. When you select this button and then select Confirm, you are returned to the worker portal, and the task status is Stopped. You can select the same task to resume work on it.

  Be aware that the person that creates your labeling tasks specifies a time limit in which all tasks much be completed by. If you do not return to and complete this task within that time limit, it will expire and your work will not be submitted. Contact your administrator for more information.

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.