Tennis video annotation guide
Separate visible contact evidence, inferred trajectories and uncertain events.
Annotator · Original teaching guide
What to learn and do
Check frame rate, interval and event definitions before separating visual evidence from motion inference. A swing may suggest a hit, but contact and landing positions need supporting frames.
Original teaching example
Original scenario: a player swings, but contact is occluded. Record the visible swing; do not present an estimated contact frame as direct observation.
Counterexample and correction
Counterexample: assigning an exact contact frame to every swing. Correction: use an interval, unknown state or review request as the task permits.
When evidence is uncertain
This example sets no universal tolerance; temporal precision and allowed states come from the current task.
Next step
Explain in your own words which judgment is supported and which remains uncertain, then continue to practice. Practice requires registration or sign-in. Reading this introduction is not course completion, assessment success or professional certification.
Continue to learning and practice