How Computer Vision & AI Pose Tracking Work in Web Browsers
Discover the engineering behind browser-based 3D skeletal landmark detection, MediaPipe trigonometry, background segmentation, and zero-latency rep counting.
1. 33-Keypoint 3D Skeletal Landmark Detection
Modern browser-based motion tracking relies on deep neural network architectures (such as MediaPipe Pose) to detect 33 standardized 3D body keypoints in real time. These keypoints map critical anatomical landmarks including shoulders, elbows, wrists, hips, knees, ankles, and heels. Each keypoint provides normalized (x, y, z) spatial coordinates along with a confidence metric determining visibility.
2. Real-Time Trigonometric Joint Angle Calculations
Once skeletal keypoints are extracted from a video frame, vector mathematics and 3D Euclidean geometry determine precise joint flexion and extension angles. For example, to calculate elbow flexion, the system computes the 3D angle between the shoulder-elbow vector and the elbow-wrist vector using dot product vector formulas. State-machine algorithms track these angle transitions across temporal frames to count reps deterministically.
3. Hybrid Local & Cloud AI Architecture
Motion Coach operates on a hybrid privacy and AI architecture. Camera feeds, 3D pose landmark tracking, facial masking, and rep counting execute locally inside your web browser. For deep biomechanical form analysis, sanitized keyframe snapshots and anonymized pose telemetry are securely sent to Google Gemini AI models in the cloud.
4. Background Segmentation & Facial Anonymization
To comply with strict global privacy regulations (GDPR Art. 9 and US BIPA), optional cloud biomechanical evaluations undergo strict pre-processing. Local browser algorithms apply blackout facial overlays and background neural segmentation to strip away the user's personal environment. Only anonymized, masked skeletal snapshots are transmitted for AI evaluation.
Interactive Checker: Try Camera Form Tracking - Experience real-time browser pose estimation on 100+ exercises with zero video uploads.