← Kusal Nirmala KaratePose-AI
Undergraduate Research Proposal · Revision 2

KaratePose-AI

Kinematic Refinement of Coordinate-Based Human Pose Estimation via a Physics-Informed Filter Engine for Elite Martial Arts Analytics.

A two-phase study on rigid-garment occlusion and event-triggered kinematic correction in martial arts pose estimation.

ProgrammeBSc (Hons) AI — Plymouth / NSBM
StatusIn Progress
Structure2 Manuscripts · 24 Months
Candidate VenuesTBD — scope & peer-review fit
Live Demo · Runs In Your Browser

This Is What Section 5.3 Looks Like, Live

The coordinate ingestion pipeline described below — MediaPipe extracting 33 landmarks per frame — running on your own device via WebAssembly. Nothing is uploaded, recorded, or sent anywhere; inference happens entirely in this browser tab.

Runs entirely in your browser tab — nothing is uploaded or recorded. Camera permission is optional.

Requires HTTPS (works once deployed — e.g. via GitHub Pages). Best in Chrome or Edge; camera access varies on Safari/iOS.

Section 01

Executive Summary & Objective

State-of-the-art (SOTA) human pose estimation (HPE) models — Google MediaPipe and YOLOv8-Pose — deliver strong accuracy on standard benchmark datasets featuring form-fitting apparel. Prior work has separately studied martial arts pose estimation (in standard apparel), loose-clothing occlusion (in winter sports), and Kalman-filtered biomechanical tracking (in sprinting) — but not the specific combination this project targets: rigid, heavyweight canvas fabric (e.g. a 14oz Karate Gi) folding under high-velocity kinetic transitions. This is a mechanically distinct occlusion pattern from loose drape-type fabric, and it has not been benchmarked or corrected for in the literature reviewed to date.

This project addresses that gap in two phases:

  • Quantify the degradation of standard coordinate-prediction models (MediaPipe, YOLOv8-Pose) under rigid-fabric occlusion and high-velocity transitions (Paper 1).
  • Develop and validate an event-triggered, physics-informed correction filter — an Extended Kalman Filter (EKF) that activates on confidence collapse rather than smoothing continuously — to reconstruct true joint trajectories and compute Center of Gravity (CoG) (Paper 2).
Section 02

Introduction & Problem Statement

SOTA computer-vision HPE frameworks suffer measurable performance degradation when exposed to two concurrent real-world variables: (1) high-velocity kinetic transitions, which introduce localized motion blur, and (2) complex material occlusion, where rigid canvas fabric folds and alters body silhouettes, collapses visual joint markers, and introduces false edge boundaries. This differs mechanically from the loose-fabric draping studied in winter-sports HPE literature: rigid canvas creates hard, false edges rather than soft occlusion. This research formulates a physics-informed post-processing pipeline that stabilizes tracking and produces reliable athletic metrics under these conditions — using consumer-grade hardware only.

Section 04

Research Objectives

01

Establish a controlled dual-garment dataset isolating rigid canvas-fabric occlusion from high-velocity martial arts kinetics, extending existing karate pose-estimation work (which assumes standard apparel) and existing loose-clothing occlusion work (which addresses draping, not folding).

02

Quantify degradation using confidence-score volatility and spatial jitter, with a pre-registered statistical comparison (Set A vs. Set B).

03

Construct a biomechanical framework (de Leva segment model) to compute live Center of Gravity and Stance Depth, following the validated approach used in markerless sprinting biomechanics.

04

Design and validate an event-triggered Extended Kalman Filter that rejects low-confidence coordinates and projects joint location via momentum — distinct from the continuous smoothing used in prior sports-HPE Kalman applications — benchmarked against a linear-interpolation baseline.

05

Publish two manuscripts — a benchmarking study and an algorithmic optimization methodology — with an honest discussion of dataset scale as a limitation.

Section 05

Methodology & System Architecture

5.1 Data Capture Protocol

A controlled dataset will be captured with an iPhone 15 Pro Max on a fixed tripod, using two settings: 4K at 60 FPS for standard tracking and inference testing, and 1080p at 240 FPS as a slow-motion baseline for visual cross-checking during blur.

Two matched conditions will be filmed performing foundational Shotokan Katas (Oi-zuki, Gedan-barai, Zenkutsu-dachi transitions): Set A is the control — tight, lightweight athletic apparel — and Set B is the experimental, occlusion condition — a heavyweight 14oz canvas Gi.

Dataset Scale

Where feasible, footage will be collected across multiple sessions and, ideally, more than one practitioner. A single-subject, single-session dataset is treated explicitly as a pilot/feasibility scope in Section 8 (Limitations), not disguised as a generalizable result.

5.2 Strengthening Ground Truth

Tight clothing (Set A) is a proxy for ground truth, not verified ground truth — MediaPipe/YOLO can still err on unoccluded footage. Following the approach used in loose-clothing HPE ground-truth work, a small number of high-contrast markers (e.g. colored tape or small reflective tags) will be placed at key joints for a subsample of takes in both conditions, enabling manual frame-by-frame verification independent of any pose-estimation model. This gives Paper 1 a semi-independent accuracy check beyond "Set A looks smooth."

5.3 Coordinate Ingestion Pipeline

A Python pipeline (OpenCV, MediaPipe, Ultralytics YOLOv8) streams both video sets frame-by-frame and logs structural joint arrays into structured DataFrames: MediaPipe contributes 33 landmarks per frame, each with (x, y, z) coordinates and a visibility/confidence score (v); YOLOv8-Pose contributes 17 keypoints per frame with bounding-box coordinates and a detection confidence score (c). All frames are indexed against key joints — ankle, knee, hip, shoulder, elbow, wrist.

5.4 Phase 1 — Material Occlusion Benchmark (Paper 1)

Two degradation vectors are isolated and quantified: confidence score volatility, mapping drops in detection confidence (v or c) for the hip and knee joints during deep-stance transitions, and spatial jitter, the frame-to-frame Euclidean displacement of each tracked coordinate.

Jitter = √[ (xt − xt−1)² + (yt − yt−1)² ]

5.5 Statistical Analysis Plan

Defined before data collection, not after. The primary comparison is jitter magnitude, Set A vs. Set B, per joint, using a Wilcoxon signed-rank test (paired, non-parametric; jitter distributions are expected to be right-skewed). Effect size is reported alongside significance (rank-biserial correlation or Cohen's d on log-transformed jitter). Confidence-score volatility is compared using the same paired non-parametric approach. Phase 2 evaluation compares EKF-corrected trajectories against both raw Set B output and a linear-interpolation baseline — not EKF against nothing.

5.6 Phase 2 — Physics-Informed Kinematic Refinement (Paper 2)

Biomechanical CoG mapping: the human body is modeled as a linked-segment system using de Leva's (1996) anatomical mass percentages (e.g. Torso ≈ 43.46%, Thigh ≈ 14.16%, Lower Leg ≈ 4.33%), following the same approach validated for markerless center-of-mass tracking in sprinting biomechanics. Global Center of Gravity for a given frame is:

XCoG = Σ(xi · wi)     YCoG = Σ(yi · wi)

where xi, yi is the midpoint of body segment i and wi is its relative anatomical mass weight.

Event-triggered state correction: unlike prior sports-HPE applications that apply Kalman smoothing continuously across every frame, this filter is designed to activate specifically on occlusion events. While confidence remains high, the filter updates its velocity model from the raw AI output. When a joint's confidence score drops below an empirical threshold (T < 0.50), the filter rejects the raw coordinate and instead projects the joint's location forward using its established momentum vector. Threshold T will be tuned on a held-out portion of the dataset, not fixed a priori. This is evaluated against a linear-interpolation baseline to demonstrate the momentum-based approach is doing more than simple gap-filling.

Simulated data — for illustration
OCCLUSION OCCLUSION T<0.50 CONFIDENCE (v)
Raw output (MediaPipe / YOLOv8) EKF-corrected trajectory Joint confidence score

Conceptual sketch of Sections 5.4–5.6: raw coordinates jitter and confidence collapses during rigid-fabric occlusion; the filter detects the confidence drop and switches to a momentum-projected estimate until confidence recovers. Synthetic values, not experimental results.

Section 06

Hardware & Software Infrastructure

The entire development loop runs on existing consumer hardware, requiring no additional budget or university compute infrastructure.

Hardware
iPhone 15 Pro Max
Data capture — 60 / 240 FPS
ASUS ROG G513 (Ryzen 7 6800H, RTX 3060 6GB)
Local ML training & inference — CUDA-accelerated YOLOv8 pipelines
MacBook Air M4
Analysis & composition — Jupyter Notebooks, LaTeX manuscript drafting
Software Stack
PythonOpenCVMediaPipe Ultralytics YOLOv8PandasNumPySciPy
Deployability Note

Lightweight consumer-grade models (MediaPipe, YOLOv8) are used deliberately, not because heavier transformer-based pose models are unknown to the field — they are, and tend to outperform on accuracy in adjacent sports benchmarks. The choice reflects a real dojo-deployment use case (no GPU cluster, no motion-capture lab) and is stated as a design decision in the manuscript, not left implicit.

Section 07

Expected Academic Contributions

Manuscript 1 · System Evaluation

A benchmark quantifying pose-model degradation under rigid-fabric occlusion combined with high-velocity martial arts kinetics — a compounding failure mode not isolated in prior karate-HPE or clothing-occlusion literature.

Manuscript 2 · Algorithmic Solution

An event-triggered EKF correction method, benchmarked against a linear-interpolation baseline, extending the Kalman + de Leva pipeline validated in sprinting biomechanics to a garment-occlusion setting.

Venue placement will depend on peer-review outcomes and is not fixed at proposal stage.

Section 08

Limitations & Threats to Validity

  • Dataset scale — a single-subject dataset (if that is the final scope) limits generalizability; this will be stated explicitly as a pilot/feasibility study, not implied to be population-level.
  • Ground truth — Set A is a proxy, not verified ground truth; the marker-assisted subsample (Section 5.2) partially, not fully, mitigates this.
  • Model scope — only MediaPipe and YOLOv8-Pose are benchmarked; transformer-based models (e.g. ViTPose) are known to outperform both in adjacent sports domains and are noted as future work rather than omitted silently.
  • Threshold tuning — the T < 0.50 confidence threshold will be empirically tuned rather than assumed correct from the outset.
Section 09

Project Timeline

01

Foundations & Environment Setup

Months 1–3

Master Python data handling; stand up the video/coordinate pipeline (Pandas, OpenCV, MediaPipe); finish literature review.

Deliverable — Working extraction script; annotated bibliography

02

Video Acquisition & Baseline Dataset

Months 4–6

Capture the controlled dual-garment dataset across multiple sessions (and additional practitioners if available); apply joint-marker ground-truth aid.

Deliverable — Complete Set A / Set B video corpus + marker-verified subsample

03

Paper 1 — Benchmarking Analysis & Write-up

Months 7–12

Run extraction on both sets; run pre-registered statistical tests; draft manuscript.

Deliverable — Manuscript 1 drafted

04

Biomechanical Integration

Months 13–16

Implement Center-of-Gravity and Stance Depth tracking on the clean Set A baseline; build linear-interpolation baseline filter.

Deliverable — Working CoG overlay + baseline filter

05

Physics-Informed Filter & Paper 2

Months 17–22

Build and validate the Extended Kalman Filter on occluded Set B data; benchmark against the baseline; draft manuscript.

Deliverable — Manuscript 2 drafted

06

Review, Revision & Submission

Months 23–24

Incorporate supervisor/peer feedback; finalize both manuscripts for submission.

Deliverable — Both manuscripts submitted

Section 10

References

de Leva, P. (1996). Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters. Journal of Biomechanics, 29(9), 1223–1230.

Echeverria, J., & Santos, O. C. (2021). Toward Modeling Psychomotor Performance in Karate Combats Using Computer Vision Pose Estimation. Sensors, 21(24), 8378.

Zhang, W., Liu, Z., Zhou, L., Leung, H., & Chan, A. B. (2017). Martial Arts, Dancing and Sports dataset: A challenging stereo and multi-view dataset for 3D human pose estimation. Image and Vision Computing, 61, 22–39.

Dael, F. A., et al. (2026). Comparative Evaluation of MediaPipe and YOLOv8 for Real-Time Pose Estimation. Proceedings of ICAAIC / Springer.

Journal of Imaging (2022). 3D Pose Estimation and Tracking in Handball Actions Using a Monocular Camera. Journal of Imaging, 8(11), 308.

Sensors (2021). Can Markerless Pose Estimation Algorithms Estimate 3D Mass Centre Positions and Velocities during Linear Sprinting Activities? Sensors, 21(8), 2889.

arXiv:2212.04820 (2022). Pose Estimation for Human Wearing Loose-Fitting Clothes: Obtaining Ground Truth Posture Using HFR Camera and Blinking LEDs.

Lu, F. AiShifu: AI Karate Pose Trainer Using Human Pose Estimation. Journal of Student Research.

This list reflects a preliminary literature scan to establish positioning and should be expanded into a full, systematically-searched related-work section before manuscript submission.

Section 11

Appendix — Self-Guided Study Index

Search terms used to accelerate independent, ahead-of-coursework learning.

Python Engineering

pandas DataFrame tutorial OpenCV read video frame by frame Formatting NumPy arrays

Computer Vision

YOLOv8 pose estimation inference MediaPipe holistic landmark mapping Detection confidence score extraction

Math, Physics & Statistics

de Leva body segment parameters Kinematic velocity vectors 1D Kalman filter from scratch Wilcoxon signed-rank test