Johannes Roth

Machine learning engineer & PhD researcher.

I build computer-vision systems, data pipelines, and software for research. I study how vision models relate to human brain activity.

Building
Horrorverse
Reading
Art & Fear

Available from January 2027

Johannes Roth smiling, in a light blue Oxford shirt with rolled sleeves and his arms crossed

Selected work

More on GitHub

Horrorverse

A horror film recommender with mood search, an explorable map of 19,000 films and an illustrated history of the genre.

Designed and built it solo: a collaborative-filtering recommender, text-embedding search, the film atlas, an AI-assisted theme analysis, accounts and a self-hosted deployment.

ReLAION-natural

Naturalness scores for all 2.1 billion images in ReLAION-2B, plus CLIP embeddings for the 500 million natural photos.

Built the GPU pipelines for classification, quality filtering and embedding extraction at billion-image scale. Downloaded over 30,000 times on Hugging Face.

Collaborations

re:vision

A community challenge testing whether findings in visual neuroscience replicate on LAION-fMRI.

Designed the data splits the challenge runs on, replicated a 118-model brain-alignment benchmark for the consortium paper, and built the website and data services.

LAION-fMRI

A deeply sampled 7T fMRI dataset: 5 people, 60 hours each, 25,000 natural images.

Designed the stimulus set, optimizing it for diversity to 2.5× the effective dimensionality of NSD and THINGS. Also built its Python package, website, 3D brain explorer and data access on AWS.

thingsvision

An open-source library for extracting and comparing features from vision models.

Third-largest contributor: added low-memory extraction, HDF5 dataset support and model-integration tests.

Open-source tools

  • slurmboard

    A lightweight dashboard for Slurm jobs, logs and resource use on HPC clusters.

  • fmriqc

    An interactive QA and review tool for fMRI data snapshots.

  • cvmanova_python

    Cross-validated MANOVA for multivariate fMRI pattern analysis.

  • pysearchlight

    Customisable searchlight analysis for Python.

  • how-to-sample

    Code and experiments for the CCN 2025 paper on sampling natural images.

  • conwell_replication

    A LAION-fMRI replication of a 118-model brain-alignment study.

Research & publications

Google Scholar

At the Max Planck Institute and University of Giessen, I study how visual representations in models relate to the human brain.

2026 · NeurIPS 2026 (accepted)

Characterizing Universal Object Representations Across Vision Models

Mahner*, Roth* et al. · Shared first author

About this paper

We compared the object similarity structure of 162 vision models to distinguish universal from model-specific dimensions, and related that structure to image properties, neural activity, and human judgments.

2025 · CCN

How to sample the world for understanding the visual system

Roth & Hebart · Oral

About this paper

How does the choice of images affect what we can learn about the visual brain? We compared image-sampling strategies using simulations and fMRI data to study dataset coverage and model generalization.

Earlier publications

Experience & education

Full CV

Experience

  • PhD Researcher · Computational Cognitive Neuroscience

    Max Planck Institute for Human Cognitive and Brain Sciences & University of Giessen

    Independent research on vision models and human brain activity, with GPU-based data pipelines, fMRI experiments, and public research software.

  • Research Scientist · Machine Learning in Medicine

    ScaDS.AI Dresden/Leipzig

    Deep-learning models for brain-tumor segmentation and predictive models for clinical data, including mortality prediction and uncertainty estimation.

  • Data Scientist / ML Engineer · Working student

    CHECK24, Travel Vertical

    Designed and deployed a production computer-vision service for 20 million hotel images. Improved recommendation-data pipelines, reducing update time by over 95%.

  • Full-Stack Developer · Freelance

    Kimetric UG

    Delivered Django websites for Hebart Lab and the THINGS Initiative, from client requirements to deployment, Linux hosting, and maintenance.

  • Data Scientist · Working student

    Webdata Solutions GmbH (now Vistex)

    Developed machine-learning models for product matching and image classification in e-commerce.

  • Data Analyst · Working student

    Mercateo Services GmbH & Co. KG

    Data integration, reporting, and testing for an AWS-based data warehouse using Apache NiFi and Pentaho.

Education

  • Doctoral candidate · Dr. rer. nat.

    University of Giessen

    Research focus: machine learning and computational neuroscience.

  • M.Sc. Computer Science

    Leipzig University · Grade 1.2

    Master’s thesis: generative deep learning for visual processing in the human brain (grade 1.1).

  • B.Sc. Business Information Systems

    Leipzig University · Grade 1.5

Expertise

Machine learning & data science
Building models and using data to understand patterns, make predictions, and support decisions.
Production ML systems
Making ML systems reliable, efficient, and maintainable in everyday use.
Data engineering
Making data accessible, consistent, and useful for analysis and applications.
Backend & web development
Building useful applications and services with clear interfaces and maintainable architecture.
Research & experimental design
Turning open questions into testable ideas, sound experiments, and clear conclusions.
Project ownership & collaboration
Shaping the work, coordinating with others, and seeing projects through.

Methods & tools

  • Python
  • PyTorch
  • scikit-learn
  • pandas
  • NumPy
  • Deep learning
  • Computer vision
  • Image segmentation
  • Embeddings
  • Feature extraction
  • Recommender systems
  • Collaborative filtering
  • UMAP
  • Model evaluation
  • Representational similarity analysis
  • fMRI analysis
  • Experimental design
  • Statistics
  • Dataset curation
  • Data services
  • SQL
  • GPU pipelines
  • SLURM / HPC
  • Linux servers
  • AWS
  • Hugging Face
  • Git
  • Research software
  • Django
  • JavaScript

Writing

All writing
  • A century of fear

    What scares us changes. An illustrated analysis of 19,302 horror films, from atomic mutants to masked killers to ghosts, on Horrorverse.

  • It's always clear from the outside

    A passage from Art and Fear and what it says about how we see other people's work versus our own.

Johannes bouldering in a mountain valley

Life outside work

Climbing, making music, books, and dinner with friends.

Meet the other side of me

Still Johannes.

A little less formal.

Here's what life looks like away from the screen: climbing, making music, reading, and having friends over for dinner.

Reading
Art & Fear, The Mind Illuminated
Johannes smiling in a T-shirt and climbing harness

A bit about me

Johannes bouldering on a rock face in a mountain valley

Movement

My love for moving my body started with joining a breakdance crew at 17. These days I mostly boulder, lift weights, and do yoga. A day in the mountains with some climbing is hard to beat.

Johannes holding an electric guitar

Music

A few years ago, I asked some friends if they wanted to start a band. Everyone said yes. We mostly play pop punk covers at birthday parties, but the dream of writing our own songs is still alive.

A colorful plate of food on a wooden table

Food

I used to be an incredibly picky eater. Now I love throwing whole food ingredients together and having friends over for dinner. Hosting is a blast, even when it gets surprisingly stressful.

A quiet forest path near the meditation hall

Meditation

Meditation and I have had an on-off relationship for over a decade. A ten-day silent retreat in 2024 changed a lot for me. I walked this forest path probably a hundred times and kept discovering something new.

On my shelves

Books, music, and movies.

Music

I listen to a bit of everything. Spotify probably knows my taste better than I do.

Books

Reading now

  • Art & Fear by David Bayles & Ted Orland
  • The Mind Illuminated by Culadasa

Loved

  • Silence by Thich Nhat Hanh
  • Old Path White Clouds by Thich Nhat Hanh
  • You Are Here by Thich Nhat Hanh
  • No Mud, No Lotus by Thich Nhat Hanh
  • Peace Is Every Step by Thich Nhat Hanh
  • When Things Fall Apart by Pema Chodron
  • Full Catastrophe Living by Jon Kabat-Zinn
  • Wherever You Go... by Jon Kabat-Zinn
  • Why We Meditate by Daniel Goleman & Tsoknyi Rinpoche
  • The Art of Living by William Hart
  • Be Here Now by Ram Dass
  • After the Ecstasy, the Laundry by Jack Kornfield
  • The Attention Revolution by B. Alan Wallace
  • The Book: On the Taboo by Alan Watts
  • The Wisdom of Insecurity by Alan Watts
  • Autobiography of a Yogi by Paramahansa Yogananda
  • Doors of Perception by Aldous Huxley
  • The Psychedelic Explorer's Guide by James Fadiman
  • Food of the Gods by Terence McKenna
  • Red Rising series by Pierce Brown
  • The Kingkiller Chronicle by Patrick Rothfuss
  • A Song of Ice and Fire series by George R.R. Martin
  • The Expanse series by James S.A. Corey
  • The Belgariad series by David Eddings
  • Mistborn series by Brandon Sanderson
  • The 13th Paladin series by Torsten Weitze
  • The Three-Body Problem by Cixin Liu
  • Dune by Frank Herbert
  • It by Stephen King
  • Island by Aldous Huxley
  • Malice by John Gwynne
  • Of Blood and Fire by Ryan Cahill
  • Gods of the Wyrdwood by R.J. Barker
  • Magician by Raymond E. Feist
  • The Dwarves by Markus Heitz
  • Uldart: Die dunkle Zeit by Markus Heitz
  • Der Turm der Bettler
  • A Wizard of Earthsea by Ursula K. Le Guin
  • Ender's Game by Orson Scott Card
  • Braiding Sweetgrass by Robin Wall Kimmerer
  • Wild by Cheryl Strayed
  • Into the Wild by Jon Krakauer
  • Into Thin Air by Jon Krakauer
  • Seven Years in Tibet by Heinrich Harrer
  • Born to Run by Christopher McDougall
  • A Search in Secret India by Paul Brunton
  • Adult Children of Emotionally Immature Parents by Lindsay C. Gibson
  • How to Do the Work by Nicole LePera
  • Why Has Nobody Told Me This Before? by Julie Smith
  • Why Zebras Don't Get Ulcers by Robert M. Sapolsky
  • Maybe You Should Talk to Someone by Lori Gottlieb
  • In the Realm of Hungry Ghosts by Gabor Mate
  • How to Change Your Mind by Michael Pollan
  • DARE by Barry McDonagh
  • Feeling Good by David D. Burns
  • A Liberated Mind by Steven C. Hayes
  • Four Thousand Weeks by Oliver Burkeman
  • Deep Work by Cal Newport
  • The Myth of Normal by Gabor Mate
  • How Not to Die by Michael Greger
  • How Not to Age by Michael Greger
  • Food Rules by Michael Pollan
  • Omnivore's Dilemma by Michael Pollan
  • Deep Medicine by Eric Topol
  • Total Immersion by Terry Laughlin
  • 24/6 by Tiffany Shlain
  • Smartphone Nation by Kaitlyn Regehr
  • It Doesn't Have to Be Crazy at Work by Jason Fried & David Heinemeier Hansson
  • The Age of Surveillance Capitalism by Shoshana Zuboff
  • How to Break Up with Your Phone by Catherine Price
  • Make Time by Jake Knapp & John Zeratsky
  • We Should All Be Feminists by Chimamanda Ngozi Adichie
  • Men Explain Things to Me by Rebecca Solnit
  • The Road to Reality by Roger Penrose
  • Surely You're Joking, Mr. Feynman! by Richard P. Feynman
  • Tools of Titans by Tim Ferriss
  • How to Win Friends and Influence People by Dale Carnegie
  • The Life-Changing Magic of Tidying Up by Marie Kondo
  • When Breath Becomes Air by Paul Kalanithi
  • Man's Search for Meaning by Viktor Frankl
  • That Good Night by Sunita Puri
Books I found okay
  • The Obstacle Is the Way cover

    The Obstacle Is the Way

    Ryan Holiday

  • Stolen Focus cover

    Stolen Focus

    Johann Hari

  • The Wim Hof Method cover

    The Wim Hof Method

    Wim Hof

  • Atomic Habits cover

    Atomic Habits

    James Clear

  • Indistractable cover

    Indistractable

    Nir Eyal

  • Waking Up cover

    Waking Up

    Sam Harris

  • Built to Move cover

    Built to Move

    Kelly Starrett

  • Kitchen Confidential cover

    Kitchen Confidential

    Anthony Bourdain

  • The Comfort Crisis cover

    The Comfort Crisis

    Michael Easter

  • The Shallows cover

    The Shallows

    Nicholas Carr

Writing

All writing

Things I'm thinking about.

  • A century of fear

    What scares us changes. An illustrated analysis of 19,302 horror films, from atomic mutants to masked killers to ghosts, on Horrorverse.

  • It's always clear from the outside

    A passage from Art and Fear and what it says about how we see other people's work versus our own.

Say hi

For research, collaborations, or a good conversation.

johannes@roth24.de

Available from January 2027