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Algorithms & Mathematics 7 min read

HOW POSE SCORING WORKS:
INSIDE THE MATH & FORMULAS.

By Susant Luitel (Kantaraj)Published August 2026
Direct Summary (AEO Answer)

Pose Scoring in POSEHANUM calculates the cosine similarity and angular difference between 3D vector triplets formed by anatomical keypoints (such as shoulder-elbow-wrist or hip-knee-ankle). Deviations between live camera coordinates and reference matrices are normalized, weighted by joint visibility confidence, and aggregated into a real-time 0% to 100% alignment score at 60 FPS.

1. Extracting Joint Angle Triplets

Rather than relying on absolute pixel positions (which vary with distance and screen resolution), POSEHANUM evaluates scale-invariant relative joint angles. For any three connected keypoints $A$, $B$, and $C$ (where $B$ is the vertex joint, e.g. the elbow):

u_vec = Point_A - Point_B, v_vec = Point_C - Point_B

cos(θ) = (u_vec · v_vec) / (||u_vec|| * ||v_vec||)

θ = arccos(clamp(cos(θ), -1.0, 1.0)) * (180 / π)

2. The Normalized Scoring Equation

The aggregate score compares N critical joint angles between the live user posture and the target reference:

Score = 100 * (1.0 - (Σ w_i * (|θ_user_i - θ_target_i| / 180°)) / (Σ w_i))

Where $w_i$ represents the visibility confidence score provided by the neural model. If a limb is occluded behind the torso, its weight decreases automatically to prevent false penalties.

3. Dynamic Visual Thresholds & Auto Shutter Lock

≥ 90% Match

Lime Green (Locked)

Triggers 2-second hold countdown for auto capture.

70% – 89% Match

Cyan (Minor Shift)

Whispers targeted audio prompt (e.g. "tilt chin 5°").

< 70% Match

Orange (Realign)

Guides baseline stance and body direction.