Radar Signal Processing · Multimodal Cardiac Research

Find cardiac timing candidates
in contactless chest motion.

A research prototype that aligns ECG electrical anchors, SCG mechanical references, and non-contact FMCW radar morphology on a beat-relative axis for AO/AC candidate and PEP/LVET/QS2 analysis.

Explore the pipeline Algorithm notes Code reference

3 signalsECG · SCG · FMCW Radar

Beat-wiseR-peak anchored alignment

AO / ACMorphology-based candidates

PEP · LVET · QS2CTI analysis outputs

Actual Experiment Evidence

Hardware built and used in the study

These user-captured photographs show the actual ECG, SCG, and FMCW radar hardware and measurement setup. They are not AI-generated or composited equipment; public derivatives use only orientation correction, deterministic cropping, resizing, and privacy blur.

Collage of six actual ECG, SCG, and FMCW radar experiment photographs — Six actual experiment views: ECG acquisition, SCG module, STM32 acquisition, wearable session, Lead II electrodes, and BGT60TR13C radar.

ECG-acquisition portion with breadboard analog front-end and STM32 NUCLEO-F411RE — **Experimental System Overview**ECG-acquisition portion of the multimodal setup; this image alone does not show the complete three-modality system.

Actual ESP-32S and MPU6050 SCG acquisition module — **ESP-32S and MPU6050 SCG Module**Six-axis IMU module configured to acquire chest mechanical-motion components.

Actual breadboard ECG circuit connected to STM32 NUCLEO-F411RE — **ECG AFE and STM32F411**Amplification and filtering stages connected to NUCLEO-F411RE for ADC acquisition and UART transport.

Actual measurement session with a chest-mounted SCG module — **Chest-Mounted SCG Session**The module acquires mechanical-motion data for later beat alignment; the photo alone does not prove synchronized acquisition.

Actual Lead II ECG measurement with limb electrode clips — **Lead II ECG Measurement**ECG R-peaks serve as alignment anchors for ECG, SCG, and radar beats—not as AO/AC ground truth.

Infineon BGT60TR13C radar evaluation module used for non-contact chest micromotion — **Infineon BGT60TR13C Radar**Radar-derived AO/AC values are morphology-based timing candidates, not direct valve images.

01 · Radar Path

From range bin to cardiac component

The pipeline selects a region of interest after range FFT, extracts phase displacement, and suppresses respiration/motion components before beat analysis.

FMCW radar range FFT and region of interest example — 1. Range FFT and ROI

Phase displacement extraction from the selected range bin — 2. Phase displacement

Respiration component cancellation example — 3. Respiration suppression

02 · Alignment

One beat axis for three signals

ECG R-peaks provide stable beat anchors; SCG references and radar morphology are compared on the same relative time axis.

ECG R peak detection example — Electrical beat anchor

Beat alignment before and after example — Beat-relative alignment

03 · Detection

Candidate fusion, not one rule

Slope, morphology, template, wavelet, and notch detectors contribute timing candidates; confidence and SQI reject unstable beats.

Fusion of AO and AC timing candidates — Detector ensemble and fusion

SQI beat acceptance and rejection — Signal-quality gate

AO candidate

Early-systolic shape

Upstroke, slope, and template similarity propose an opening-related landmark.

AC candidate

Late-systolic shape

Notch, inflection, and temporal continuity track a closure-related candidate.

Quality

Record acceptance

Beat quality and detector agreement make both outputs and exclusion reasons inspectable.

04 · Paper-source evidence

Reviewed figures from the supplied paper

The paper PDF was audited at the embedded-image level. Four substantive figures are public; three companion mask layers were not duplicated. No participant-level raw data or subject CSV is included.

Paper workflow from ECG SCG and radar acquisition to AO AC comparison — Paper workflow · Source-Derived

Normalized ECG SCG and radar waveforms on a common time interval — Multimodal waveform excerpt · Source-Derived

Beat-relative ECG SCG landmarks and radar AO AC candidates — Beat-relative landmarks · Source-Derived

Radar minus SCG relative AO and AC timing difference distributions — Relative timing distribution · Source-Derived

05 · Evidence Boundary

Separate implementation from validation

The repository includes analysis code, firmware, configurations, synthetic algorithm diagrams, and four paper-source figures. It does not publish participant raw data or subject-level result CSV, and it makes no clinical performance claim.

Conceptual PEP LVET and QS2 cardiac time intervals — CTI definitions after beat-wise landmark selection

Item	Repository state	Meaning
Analysis pipeline	Implemented	Python processing, detectors, SQI, and export documented
Embedded acquisition	Documented	STM32 ECG and ESP32 MPU6050 SCG firmware included
Public raw data	Not included	Only synthetic explanatory figures are public
Absolute valve-event validation	Future validation	Requires independent echo, ICG, or PCG reference