Align

Visual AI Posture Ritual for Smart Mirrors

Technical Design Document (TDD) Note: All images as of February 20, 2026 are prototypes.

1. Overview

Align is a smart mirror morning reset application that uses computer vision to guide users through gentle posture-alignment stretches and provide a brief posture assessment.

The system combines:

Guided micro-stretches
Real-time pose tracking
Stability detection (3-second hold confirmation)
A lightweight posture evaluation

Align is designed to be:

Calm
Privacy-forward
Minimal
Non-diagnostic
Modular within Mirror Core architecture

2. Product Vision

Modern users often wake up feeling misaligned due to:

Forward head posture
Shoulder rounding
Asymmetry from sleep position
Screen-heavy lifestyles

Align provides:

A 2–3 minute visual AI ritual that gently resets posture and promotes alert alignment at the start of the day.

The goal is not medical correction.
The goal is awareness and embodied presence.

3. System Architecture

3.1 High-Level Architecture

Camera Input ↓ Pose Estimation (MediaPipe Pose) ↓ Landmark Extraction ↓ Pose Evaluator + Stability Engine ↓ UI State Controller ↓

Mirror Display

3.2 Core Components

1. Camera Module

Captures real-time video feed
No default storage
On-device processing preferred

2. Pose Estimation Engine

MediaPipe Pose
Extracts:
- Nose
- Ears
- Shoulders
- Hips
- Spine alignment landmarks

3. Stability Engine

Calculates landmark variance
Detects 3-second hold stability
Threshold-based confirmation

4. Posture Evaluator

Computes:

Forward head position
Shoulder symmetry
Spine vertical alignment

5. UI State Controller

Manages:

Stretch progression
Timer logic
Chime trigger
Posture summary display

4. Functional Requirements

4.1 Stretch Ritual Mode

Align includes 5 guided movements:

Chin tuck / tall neck
Shoulders back + down
Neck stretch (left)
Neck stretch (right)
Standing reach + spine lengthening

For each stretch:

Display stick-figure reference
Show instruction text
Detect approximate pose match
Start 3-second stability timer
Play gentle chime on successful hold
Progress automatically

4.2 3-Second Hold Detection

Logic:

Measure landmark position change per frame
Calculate variance over rolling window
If variance < stability threshold for 3 seconds:
- Confirm hold
- Trigger audio feedback
- Advance state

4.3 Posture Check Mode

After final stretch:

Display simple posture indicators:

Head Position
- Neutral
- Forward
Shoulder Alignment
- Even
- Uneven
Alert Indicator
- Aligned
- Warming Up

Optional: Display one gentle recommendation.

5. Posture Evaluation Logic (MVP)

5.1 Forward Head Detection

Measure horizontal displacement between:

Nose
Shoulder midpoint

If displacement > threshold: → classify as "Forward"

5.2 Shoulder Symmetry

Compare:

Left shoulder Y-coordinate
Right shoulder Y-coordinate

If difference > tolerance: → classify as "Uneven"

5.3 Spine Verticality (Optional MVP+)

Evaluate alignment of:

Nose
Shoulder midpoint
Hip midpoint

Measure deviation from vertical axis.

6. Non-Functional Requirements

Real-time performance (≥ 15 FPS)
On-device processing preferred
No video stored by default
Clear lighting dependency messaging
Accessible UI contrast
Gentle language tone

7. Privacy Considerations

Align is designed as:

On-device inference
No automatic video storage
No facial identity tracking
No biometric database creation

Future extensions requiring storage must:

Request explicit consent
Provide local-only mode

8. MVP Scope

Included

5 stretch prompts
3-second hold detection
Basic posture check (head + shoulders)
Soft chime feedback
Clean UI

Not Included

Medical diagnostics
Injury detection
Long-term analytics dashboard
Emotion recognition
Facial mood analysis

9. Risks & Constraints

Risk	Mitigation
Lighting variability	Add lighting notice
Loose clothing misalignment	Recommend fitted posture scan
Camera angle distortion	Suggest fixed mirror height
Over-classification	Keep binary categories