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Stefan Baumann

@stefanabaumann.bsky.social
1.3K followers 659 following 145 posts

PhD Student at @compvis.bsky.social & @ellis.eu working on generative computer vision. Interested in extracting world understanding from models and more controlled generation. 🌐 stefan-baumann.eu

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Stefan Baumann @stefanabaumann.bsky.social · 13/04/2026
We also release OWM, a benchmark for open-world sparse motion prediction in in-the-wild scenes. You only ever observe one future, but the model should capture all plausible ones -- evaluating that properly needed a new benchmark.
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Stefan Baumann @stefanabaumann.bsky.social · 13/04/2026
Where this gets fun: billiard shot planning. Sample thousands of "what if I strike it this way?" rollouts, pick the best one, execute. Same training data, same compute budget. Myriad sinks the shot 78% of the time. Best video model: 16%. You can plan well when you can actually explore enough futures
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Stefan Baumann @stefanabaumann.bsky.social · 13/04/2026
Why? 2,200 samples/min on one GPU vs. ~0.05-0.7 for video models. On our open-world motion benchmark, Myriad (665M params) matches or beats models with 4.5-14B params in accuracy. Match the compute budget between models, and the gap becomes massive.
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Stefan Baumann @stefanabaumann.bsky.social · 13/04/2026
From an image, we predict point trajectories with an efficient model -- one timestep at a time, like mentally unrolling a chain of interactions. No frames. No rendering. Just dynamics. This avoids the "visual tax": the enormous cost video models pay to generate every pixel to reason about motion.
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Stefan Baumann @stefanabaumann.bsky.social · 13/04/2026
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
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Stefan Baumann @stefanabaumann.bsky.social · 13/03/2026
I don't know what your colleague did, but you can do significantly better than 0.0013 if you use assistance. All of these samples still had at least a distance of 1 in 255^3 color
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Stefan Baumann @stefanabaumann.bsky.social · 13/03/2026
As Eric already said, primarily a matter of screen quality and ambient vs screen brightness - I would not consider myself to have extraordinarily good color perception, just a bright, good screen in a dark room. Super fun though!
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Stefan Baumann @stefanabaumann.bsky.social · 17/10/2025
Classic case of xkcd 2501
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Stefan Baumann @stefanabaumann.bsky.social · 15/10/2025
⚡️ FPT generalizes from open-set training. Applications: • Articulated motion (Drag-A-Move): fine-tuned FPT outperforms specialized models for motion prediction • Face motion: zero-shot, beats specialized baselines • Moving part segmentation: emerges from formulation
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Stefan Baumann @stefanabaumann.bsky.social · 15/10/2025
⚙️ Unlike other methods, we don't regress or sample one trajectory. FPT 𝘳𝘦𝘱𝘳𝘦𝘴𝘦𝘯𝘵𝘴 𝘵𝘩𝘦 𝘧𝘶𝘭𝘭 𝘮𝘰𝘵𝘪𝘰𝘯 𝘥𝘪𝘴𝘵𝘳𝘪𝘣𝘶𝘵𝘪𝘰𝘯, enabling: • interpretable uncertainty • controllable interaction effects • efficient prediction (>100k predictions/s)
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Stefan Baumann @stefanabaumann.bsky.social · 15/10/2025
💡 Our idea: Predict 𝗱𝗶𝘀𝘁𝗿𝗶𝗯𝘂𝘁𝗶𝗼𝗻𝘀 of motion, not just one flow field instance. Given a few pokes, our model outputs the probability 𝘥𝘪𝘴𝘵𝘳𝘪𝘣𝘶𝘵𝘪𝘰𝘯 of how parts of the scene might move. → This directly captures 𝘶𝘯𝘤𝘦𝘳𝘵𝘢𝘪𝘯𝘵𝘺 and interactions.
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Stefan Baumann @stefanabaumann.bsky.social · 15/10/2025
🧠 Understanding how the world 𝘤𝘰𝘶𝘭𝘥 change is core to physical intelligence. But most models predict 𝗼𝗻𝗲 𝗳𝘂𝘁𝘂𝗿𝗲, a single deterministic motion. The reality is 𝘶𝘯𝘤𝘦𝘳𝘵𝘢𝘪𝘯 and 𝘮𝘶𝘭𝘵𝘪-𝘮𝘰𝘥𝘢𝘭: one poke can lead to many outcomes.
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Stefan Baumann @stefanabaumann.bsky.social · 15/10/2025
🤔 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 🧵👇
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Stefan Baumann @stefanabaumann.bsky.social · 26/07/2025
tl;dr: do importance weighting/sampling on a sequence level, not a token level. Makes everything behave much better (see below) and makes more sense from a theoretical perspective, too. Paper: www.arxiv.org/abs/2507.18071
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Stefan Baumann @stefanabaumann.bsky.social · 26/07/2025
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.
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Stefan Baumann @stefanabaumann.bsky.social · 25/07/2025
Absolutely 100% this. Who would want to read papers like VGG-T
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Stefan Baumann @stefanabaumann.bsky.social · 14/02/2025
What a PhD, fantastic work! Two incredible banger papers already, and now this one. And all that in actually three years. Really looking forward to what you'll be up to next!
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Stefan Baumann @stefanabaumann.bsky.social · 04/12/2024
My i's, it i's
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Stefan Baumann @stefanabaumann.bsky.social · 24/11/2024
sup
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