Research Engineer — Computer Vision & Machine Learning

Hendrik Joël

Software engineer by training and by habit — backends, cloud infrastructure and systems that have to keep running. My recent focus has been machine learning and computer vision: turning video into measurement, and building the engineering around it that makes the results reproducible.

Amsterdam, Netherlands MSc Computer Science

Portrait of Hendrik Joël

01 About

Computer science engineer with a research background in computer vision and a broad, hands-on foundation across the stack — from production backends and cloud deployment to GPU inference, CI/CD and applied machine learning.

My MSc thesis on 3D human pose estimation in football was developed with Borussia Dortmund and Tactive Sports, and has been invited for journal publication. Alongside research I co-founded a software company, built AI-driven quality systems in industry, and shipped full-stack products end to end.

I like moving between research and product delivery, and I pick up new tools and domains quickly.

Based in
Amsterdam, NL
Focus
Computer vision · Applied ML
Degree
MSc Computer Science, VU Amsterdam
Languages
German (native) · English (C2) · Spanish

02 Research

MSc Thesis · 2025 – 2026 · Grade 9/10

“From Pixels to Poses”
Monocular 3D Human Pose Estimation in Broadcast Football

Vrije Universiteit Amsterdam — in collaboration with Borussia Dortmund (BVB) and Tactive Sports Amsterdam

56.3%MPJPE reduction
1invited publication
  • Built a five-stage pipeline that segments, tracks and re-identifies individual players in broadcast video and reconstructs their 3D pose — SAM 3, ByteTrack with OSNet re-ID, ViTPose-H and MotionBERT assembled into one system.
  • Designed and trained a Spatio-Temporal Pose Refinement Transformer as a post-hoc correction stage, with a learnable skeleton adjacency bias and a composite loss enforcing temporal smoothness, bone-length integrity and bilateral symmetry.
  • Cut mean per joint position error from 184.0 mm to 80.4 mm, and mean body facing direction error from 52.3° to 21.5°.
  • Established that the gain comes from learned structural priors, not filtering: Gaussian temporal smoothing improves the baseline by less than 1%.
  • Generated ground truth from a 90-minute match in a modified Unity football simulator, and trained on the Snellius national HPC cluster.

Publication — H. Joël. From Pixels to Poses: A Supervised Spatio-Temporal Refinement Pipeline for Monocular 3D Human Pose Estimation in Broadcast Football. Invited for journal publication; manuscript in preparation, 2026.

Read the full write-up

03 Projects

Research, product and client work. Open any project for the full write-up.

Selected work

Professional

Coursework & fundamentals

04 Experience

  1. 2025 – present

    AI Systems & Quality Engineering Consultant Internship

    Hansa Industrie Technology · Viersen, Germany

    • Built a complete dashboard and management application for capturing, aggregating and analysing machine data across the production line.
    • Contributed to the design of AI-driven quality control systems, including a feasibility study on automated defect detection in licence plate manufacturing.
  2. Jun – Aug 2025

    IT & Data Analyst Internship

    ZECCO Sportkommunikation GmbH · Germany

    • Collected, cleaned and analysed performance and engagement data for digital sports communication projects.
    • Built and maintained data workflows, dashboards and internal tooling.
  3. 2022 – 2024

    Co-Founder & Backend Developer

    Ceilbit · Amsterdam, Netherlands

    • Co-founded a software company; designed backend architectures, APIs and databases with React frontends.
    • Deployed scalable web applications on AWS with automated CI/CD (GitHub Actions, Docker) for reproducible releases.
    • Delivered production systems for multiple clients, including the University of Enschede.

Education

  1. 2024 – 2026

    MSc Computer Science — Software Engineering & Green IT

    Vrije Universiteit Amsterdam / Universiteit van Amsterdam

  2. 2021 – 2024

    BSc Computer Science

    Vrije Universiteit Amsterdam · Minor in Data Science

    • Thesis: memory-hard proof-of-work, replacing SHA-256 with Argon2 in Hashcash; CUDA benchmarks quantifying reduced GPU/ASIC advantage.
  3. 2021

    International Baccalaureate

    ISR International School on the Rhine · Neuss, Germany

05 Skills

Machine Learning

  • PyTorch
  • ONNX / ONNX Runtime
  • Transformers
  • Vision foundation models
  • Fine-tuning
  • Mixed-precision GPU training
  • HPC clusters

Computer Vision

  • 3D pose estimation & lifting
  • Multi-object tracking (ByteTrack)
  • Re-identification (OSNet)
  • Segmentation (SAM 3)
  • Object detection (YOLO)
  • Homography & camera geometry
  • Biomechanical constraints

Programming

  • Python
  • C++ (HPC, CUDA)
  • C
  • JavaScript / TypeScript
  • React
  • SQL

Engineering

  • GitHub Actions
  • Docker
  • CI/CD pipelines
  • AWS
  • FastAPI
  • Elasticsearch / Kibana
  • Database design & query optimisation

Certifications Cisco Networking Certificate Interests Football, strength training and running, skiing, Raspberry Pi homelab

Let’s talk

Open to research engineering and applied ML roles, and always happy to talk about computer vision, sports analytics, or anything that turns messy video into numbers.

hendrikjoel21@gmail.com