Signal Processing Developer

We’re building a camera-based biometric measurement system for a mobile health app. The core technology: remote photoplethysmography (rPPG) — using the phone camera to measure heart rate variability without any hardware.

The Technical Challenge

• React Native (Expo bare workflow) mobile app

• Fingertip PPG via rear camera + flash (primary method)

• Face rPPG via front camera (secondary/accessibility method)

• Real-time signal processing: RGB extraction ? bandpass filter ? POS/CHROM algorithm ? RR intervals ? RMSSD + coherence

• Signal quality gating (SNR-based: HIGH / MEDIUM / LOW / NONE)

• Coherence score (0.0–1.0) drives real-time Lottie animation parameters

• Offline-first: all computation on-device, zero API calls, zero per-session cost