Stefan Baumann
stefanabaumann.bsky.social
Stefan Baumann
@stefanabaumann.bsky.social
PhD Student at @compvis.bsky.social & @ellis.eu working on generative computer vision.

Interested in extracting world understanding from models and more controlled generation. 🌐 https://stefan-baumann.eu/
Pinned
You don't imagine the future by mentally rendering a movie. You trace how things move -- abstractly, sparsely, step by step.
We built a model that does exactly this. It predicts motion, not pixels -- and it's 3,000× faster than video world models.
Myriad, accepted at
@cvprconference.bsky.social
Reposted by Stefan Baumann
RayDer: Scalable Self-Supervised Novel View Synthesis from Real-World Video

Ulrich Prestel, @stefanabaumann.bsky.social, @rmsnorm.bsky.social, Björn Ommer

tl;dr:nuisance variable, architectural unification, and autoregressive pose learning->explicit dynamic state handling

arxiv.org/abs/2605.31535
June 1, 2026 at 10:40 PM
Reposted by Stefan Baumann
Diffusion models treat every part of an image equally.
→ Same number of steps. Same compute.

But images aren’t uniform. 🤔

Some regions are easy, others are hard.

So why force the model to treat them the same? 🧵
May 26, 2026 at 3:30 PM
Reposted by Stefan Baumann
Video diffusion models learn motion indirectly through pixels.

But motion itself is much lower-dimensional.

We introduce 64× temporally compressed motion embeddings that directly capture scene dynamics.

This enables efficient planning -> 10,000× faster than video models.

🧵👇
April 14, 2026 at 10:10 AM
Reposted by Stefan Baumann
Great to see corroborating evidence to our motion-forecasting.github.io work from other groups!

Check out this concurrent great work from
@stefanabaumann.bsky.social, @jannik-w.bsky.social, @tommymarto.bsky.social, Mahdi M. Kalayeh, and Björn Ommer (@compvis.bsky.social)
You don't imagine the future by mentally rendering a movie. You trace how things move -- abstractly, sparsely, step by step.
We built a model that does exactly this. It predicts motion, not pixels -- and it's 3,000× faster than video world models.
Myriad, accepted at
@cvprconference.bsky.social
April 13, 2026 at 6:44 PM
You don't imagine the future by mentally rendering a movie. You trace how things move -- abstractly, sparsely, step by step.
We built a model that does exactly this. It predicts motion, not pixels -- and it's 3,000× faster than video world models.
Myriad, accepted at
@cvprconference.bsky.social
April 13, 2026 at 10:00 AM
Reposted by Stefan Baumann
Last year Molmo set SOTA on image benchmarks + pioneered image pointing. Millions of downloads later, Molmo 2 brings Molmo’s grounded multimodal capabilities to video 🎥—and leads many open models on challenging industry video benchmarks. 🧵
December 16, 2025 at 4:52 PM
Reposted by Stefan Baumann
Oof
November 28, 2025 at 2:52 PM
Reposted by Stefan Baumann
RoMa v2 is now out! (github.com/Parskatt/rom..., arxiv.org/abs/2511.15706)

Here are the main improvements we made since RoMa:
November 20, 2025 at 9:25 AM
Reposted by Stefan Baumann
Excited to share that we'll be presenting four papers at the main conference at ICCV 2025 this week!

Come say hi in Honolulu!

👋 Pingchuan, Ming, Felix, Stefan, Timy, and Björn Ommer will be attending.
October 19, 2025 at 6:06 PM
Reposted by Stefan Baumann
🤔 What if you could generate an entire image using just one continuous token?

💡 It works if we leverage a self-supervised representation!

Meet RepTok🦎: A generative model that encodes an image into a single continuous latent while keeping realism and semantics. 🧵 👇
October 17, 2025 at 10:21 AM
🤔 What happens when you poke a scene — and your model has to predict how the world moves in response?

We built the Flow Poke Transformer (FPT) to model multi-modal scene dynamics from sparse interactions.

It learns to predict the 𝘥𝘪𝘴𝘵𝘳𝘪𝘣𝘶𝘵𝘪𝘰𝘯 of motion itself 🧵👇
October 15, 2025 at 1:56 AM
Reposted by Stefan Baumann
“Everyone knows” what an autoencoder is… but there's an important complementary picture missing from most introductory material.

In short: we emphasize how autoencoders are implemented—but not always what they represent (and some of the implications of that representation).🧵
September 6, 2025 at 9:20 PM
I'm calling it now, GSPO will be the next big hype in LLM RL algos after GRPO.

It makes so much more sense intuitively to work on a sequence rather than on a token level when our rewards are on a sequence level.
July 26, 2025 at 7:41 PM
Reposted by Stefan Baumann
🎉 Excited to share that our lab has three papers accepted at CVPR 2025!

Come say hi in Nashville!
👋 Johannes, Ming, Kolja, Stefan, and Björn will be attending.
June 9, 2025 at 7:28 AM
Reposted by Stefan Baumann
If you are interested, feel free to check the paper (arxiv.org/abs/2506.02221) or come by at CVPR:

📌 Poster Session 6, Sunday 4:00 to 6:00 PM, Poster #208
Diff2Flow: Training Flow Matching Models via Diffusion Model Alignment
Diffusion models have revolutionized generative tasks through high-fidelity outputs, yet flow matching (FM) offers faster inference and empirical performance gains. However, current foundation FM mode...
arxiv.org
June 6, 2025 at 3:48 PM
Reposted by Stefan Baumann
Here's the third and final part of Slater Stich's "History of diffusion" interview series!

The other two interviewees' research played a pivotal role in the rise of diffusion models, whereas I just like to yap about them 😬 this was a wonderful opportunity to do exactly that!
History of Diffusion - Sander Dieleman
YouTube video by Bain Capital Ventures
www.youtube.com
May 14, 2025 at 4:11 PM
Reposted by Stefan Baumann
#KostasThoughts: Another major conference review drop is around the corner. In baseball, a .300 average is elite. In research, it’s a familiar reality: submitting to top conferences means rejections happen. Keep swinging!
May 7, 2025 at 6:16 PM
Reposted by Stefan Baumann
I am very happy to share our latest work on the information theory of generative diffusion:

"Entropic Time Schedulers for Generative Diffusion Models"

We find that the conditional entropy offers a natural data-dependent notion of time during generation

Link: arxiv.org/abs/2504.13612
April 29, 2025 at 1:17 PM
Reposted by Stefan Baumann
New blog post: let's talk about latents!
sander.ai/2025/04/15/l...
Generative modelling in latent space
Latent representations for generative models.
sander.ai
April 15, 2025 at 9:40 AM
Reposted by Stefan Baumann
And the CVPR oral decisions are out! (on Openreview)
April 4, 2025 at 3:25 PM
Reposted by Stefan Baumann
Introducing VGGT (CVPR'25), a feedforward Transformer that directly infers all key 3D attributes from one, a few, or hundreds of images, in seconds!

Project Page: vgg-t.github.io
Code & Weights: github.com/facebookrese...
March 17, 2025 at 2:08 AM
Reposted by Stefan Baumann
Introducing DaD (arxiv.org/abs/2503.07347), a pretty cool keypoint detector.
As this will get pretty long, this will be two threads.
The first will go into the RL part, and the second on the emergence and distillation.
March 11, 2025 at 3:05 AM
Reposted by Stefan Baumann
The fate of your #CVPR2025 submission
February 15, 2025 at 7:45 PM
Reposted by Stefan Baumann
🤔When combining Vision-language models (VLMs) with Large language models (LLMs), do VLMs benefit from additional genuine semantics or artificial augmentations of the text for downstream tasks?

🤨Interested? Check out our latest work at #AAAI25:

💻Code and 📝Paper at: github.com/CompVis/DisCLIP

🧵👇
January 8, 2025 at 3:54 PM
Reposted by Stefan Baumann
What I like to do when considering a new dataset is to train a simple classifier and look at 'the most confident errors'.
Recently with NICO: Apart from a class, the images have a context, one of them is 'autumn'. There is also a pumpkin class. Surprise surprise, many autumn images contain pumpkins.
December 10, 2024 at 7:02 PM