Do you work out to be in shape or are you, maybe, a football fan? Some practice sports to maintain health and mindfulness, others enjoy watching matches with friends. Regardless of our lifestyle and preferences, sports is definitely an integral part of our reality. Like any other significant realm of our daily lives and world economy, sport is inevitably subject to technological advancements.
Today, in 2022, the real-time football analytics or sensor-equipped F1 cars are no longer faraway tech fantasies. In fact, the progress goes much beyond: the most developed companies have already employed artificial intelligence and computer vision in sports to tackle various challenges. Given the great impact that technology has brought into sports, there is no doubt that artificial intelligence and machine learning will continue to push this field forward.
In this article, we will particularly focus on the role of computer vision in sports throught the following breakdown:
- Computer vision in a nutshell
- Applications of computer vision in sports
- Challenges and limitations
- Sports datasets
- Key takeaways
Computer vision in a nutshell
Computer vision is the ability of computers or machines to process visual information such as digital images, videos, and more. We at SuperAnnotate have compiled several articles to give you a headstart if you’re new to the industry:
- Introduction to computer vision: History and applications
- Top 3 trends in computer vision for 2022
- Machine learning and computer vision terms: All you need to know
- Top 15 computer vision libraries
- Top 15 must-read computer vision books
- Best computer vision courses for 2022
Without wasting words, let’s jump into the use-cases of computer vision in sports.
Applications of computer vision in sports
Most major sports involve fast and swift motion that is hard to follow and perceive with a naked eye. The ability to follow this motion is the first and most important application of machine learning in sports. Besides, computer vision sports solutions help process vast amounts of visual data received throughout the games to make match-related decisions in real-time, develop new training schemes, and much more. These solutions especially help in data collection, analysis, and prognosis. Below are some of the recent applications of computer vision in sports:
Player tracking is one of the most popular computer vision tasks in sports. This involves detecting a single player or following several players at once with bounding boxes or key-point annotations (skeletons). Why are coaches or performance analysts interested in tracking players? The main reason is that it allows us to analyze how individual players move throughout the game and detect patterns in their behavior.
Not only can computer vision systems detect and track players, but they’re also capable of generating semantic information. Machine learning can create context on players’ actions and see, assume or predict if the player has the ball, whether he/she passes, runs, defends, etc.
This use of technology in sports provides another possible advantage – a computer vision-powered system can suggest optimal player position and display a comparison with actual positions in that specific game. In that way, players will clearly see the areas of growth and coaches will be able to better analyze players’ performance.
Tracking ball movement is important for extracting information from ball-based sports, especially racket or bat-and-ball sports such as tennis, cricket, badminton, and more. Computer vision models can help record the ball movement in three dimensions, show exactly where a ball hit the ground, and even predict its future trajectory to determine whether it would have hit the wicket.
In other words, computer-vision-powered ball tracking systems assist in:
- Ball detection
- Trajectory tracing
- Game results prediction
For sports such as basketball, volleyball, and soccer, this kind of ball tracking is more complicated because the ball can be hidden from view behind the players. Or alternatively, players’ interactions with the ball can be rapid and unpredictable.
Many people are turning to virtual classes to meet the growing need for mental rewiring and well-being with social distancing around. For example, both pilates and yoga are easy enough to do at home, however — especially for a beginner — it is important to try a class or two taught by a seasoned instructor, in a private or group setting, to learn how to exercise safely and avoid injuries.
That’s where computer vision, particularly pose estimation steps in. Pose estimation is a computer vision task aimed at predicting and tracking the location of a person or object and 3D pose estimation-based apps are here to assist human fitness trainers. Using abundant motion tracking data, these technologies can analyze every movement of the user and provide them with detailed live feedback. This type of collaboration with a virtual coach helps receive real-time feedback and prevent injuries when exercising.
Challenges and limitations
Computer vision in sports heavily depends on camera systems to obtain and later process sports footage. Typically, several cameras are placed close to the location where the event takes place, like the sidelines of a training field or the stands in a stadium during a match. The angle, positioning, hardware, and other shooting setups differ significantly from sport to sport, and even within the same match. This poses a certain challenge for computer vision systems because they also need to be adjusted and tailored to specific matches and footage acquisition styles. A few more challenges include:
- Advanced filming equipment is unavailable for many sports clubs and performance analysis departments.
- Broadcast cameras often change their pan, tilt, and zoom which presents additional challenges for computer vision video processing systems to adjust to dynamically changing data they receive.
- In certain circumstances, it may be challenging for computer vision video processing systems to differentiate between the background and players, players and objects, players with the same outfit, and more.
Computer vision has addressed these shortcomings to some measure. For example, computers are now able to distinguish between the ground, players, and other foreground objects due to image processing. Or else, color-based segmentation algorithms allow detecting the grass by its green color, facilitating pitch zone detection, tracking moving players, and identifying the ball.
For those interested in digging further into the topic and experimenting with computer vision in sports, here is a list of ready-made public datasets.
- Yoga pose image classification dataset
The dataset contains a total of 5994 files divided among 107 directories (folders), each representing a distinct yoga type. This dataset can help solve pose estimation tasks in yoga applications.
2. OpenTTGames dataset
OpenTTGames is a public dataset with five training and seven testing videos for computer vision tasks in table tennis. Each video includes ball coordinates markup files, a folder with segmentation masks, and a total of 4271 manually annotated events of 3 classes - ball bounces, net hits, and empty events.
3. NBA SportVU
The NBA SportVU dataset is publicly available on GitHub. It contains player and ball trajectories for 631 games from the 2015-2016 NBA season. The tracking data is in the JSON format, and each moment includes information about the identities of the players on the court, identities of teams, the period, the game clock, and the shot clock.
PoseTrack is an open-source dataset for human pose estimation and articulated tracking in video. With both training and test sets, PoseTrack covers:
- 1356 video sequences
- 46K annotated video frames
- 276K body pose annotations
5. KTH Multiview Football Dataset II
Open for academic research, the KTH Multiview Football Dataset II consists of two major sets with 3D and 2D ground-truth pose estimation data. The 3D set alone includes 800 time frames, captured from 3 views (2400 images), 2 different players, and two sequences per player with 14 annotated joints.
Artificial intelligence is finding its way into all sorts of different sports, from baseball to football and even golf. In this article, we touched upon some of the most common use-cases of computer vision in sports and illustrated examples of existing applications. The most popular computer vision tasks in sports include player and ball tracking, pose estimation for injury prevention, segmentation for differentiating the background from players, and more.
Because computer vision is all about how you process visual data, we suggest you take advantage of public sports datasets and experiment with your projects. For more elaborate projects crafting your own image or video datasets is necessary, and that’s where SuperAnnotate can help you build ground-truth data for your AI.