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Creating Pose Skeletons from Scratch – FiftyOne Tips and Tricks – September 15, 2023

Welcome to our weekly FiftyOne tips and tricks blog where we cover interesting workflows and features of FiftyOne! This week we are getting ready for the spooky season with some skeletons. We aim to cover the basics of creating a skeleton dataset using keypoints starting with just an image.

Wait, What’s FiftyOne?

FiftyOne is an open source machine learning toolset that enables data science teams to improve the performance of their computer vision models by helping them curate high quality datasets, evaluate models, find mistakes, visualize embeddings, and get to production faster.

Ok, let’s dive into this week’s tips and tricks! Also feel free to follow along in our notebook or on YouTube!

Pose Skeletons

In computer vision, pose skeletons are vital for understanding human or animal motion in images or videos, facilitating identification of precise body position and movement annotation. They also play a crucial role in human pose estimation datasets, aiding machine learning model training for applications in human-computer interaction, surveillance, and healthcare.

In FiftyOne, pose skeletons are stored with the Keypoints class. The Keypoints class represents a collection of keypoint groups in an image. Each element of this list is a Keypoint object whose points attribute contains a list of (x, y) coordinates defining a group of semantically related keypoints in the image.

For example, if you are working with a person model that outputs 18 keypoints (left eye, right eye, nose, etc.) per person, then each Keypoint instance would represent one person, and a Keypoints instance would represent the list of people in the image.

Preparing Your Dataset

Creating your own skeletons in FiftyOne is easy and quick. If you are starting from just images, start by creating a view or a dataset of the images you plan on annotating with skeletons. I chose to use the quickstart dataset as a nice example. 

import fiftyone as fo
import fiftyone.zoo as foz

dataset = foz.load_zoo_dataset(

session = fo.launch_app(dataset)

Using the FiftyOne App, I am going to tag the first person I see, which happens to be this cool skateboarder, in order to then automatically send it out for keypoint annotation using an annotation integration (in this case CVAT). 

To do so, simply select the image, click on the tag image and add “annotate” to its sample tags.

Next, we need to prepare our dataset to expect keypoint skeletons. Using dataset.skeletons, we can add our expected labels and connections for our fo.KeypointSkeleton. Two inputs are provided, labels and edges. Labels will be the parts of the skeleton we are interested in and edges are how they are connected. Note that for labels and edges, the index will always correspond to the keypoint index. Hence, in my example, “left hand” will always be my first keypoint. I also chose to break my edges into two groups whose points will connect with each other, but not the other group.

dataset.skeletons = {
   "points": fo.KeypointSkeleton(
           "left hand" "left shoulder", "right shoulder", "right hand",
           "left eye", "right eye", "mouth",
       edges=[[0, 1, 2, 3], [4, 5, 6]],

Annotating Your Skeleton

To create a skeleton we are going to need some annotated keypoints on our image. If you already have annotations prepared you can skip this step. If you are starting from scratch, no problem. Follow along to create some keypoints with FiftyOne’s CVAT integration. If you haven’t created a CVAT account yet, you will need to hop over to create one. The first step is to plug in your username and password to environmental variables.


Next, let’s grab the sample we tagged earlier and create a view for annotation.

ann_view = dataset.match_tags("annotate")

After, we want to launch the CVAT tool with our image. We provide an annotation key to retrieve our results later, as well as the new label field and type that we will be annotating for.

# A unique identifer for this run
anno_key = "skeleton"

# Upload the sample and launch CVAT
anno_results = ann_view.annotate(

As we annotate, make sure to annotate the keypoints in the correct order for the skeleton! After you are finished and the job is completed, load the new keypoints in.

We can load our annotations back to FiftyOne like so after completion:

ann_view.load_annotations("skeleton", cleanup=True)

session.view = ann_view


Just like that, we’ve explored the smooth process of preparing your dataset and annotating it with skeletons using FiftyOne. Whether you’re starting from scratch or have existing annotations, FiftyOne’s annotation integrations and keypoints simplified skeleton workflow allows you to efficiently define labels and connections for keypoints on your images.

With just a few lines of code, your dataset can be configured to expect keypoint skeletons, and the CVAT tool facilitates the creation of annotated skeletons in the correct order. You can easily load these annotations back into your dataset for further analysis, providing a valuable resource for enhancing your computer vision and machine learning projects. FiftyOne makes the entire process accessible to both beginners and experienced practitioners, empowering you to tackle complex tasks and develop advanced computer vision models.

Enjoy your skeletons!

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