To teach the model to recognize when a concept is *not* in an image, the team heavily annotated negative phrases. This massive volume of negative data was critical for building a robust recognition capability and preventing the model from falsely detecting objects that are not present.
The key innovation was a data engine where AI models, fine-tuned on human verification data, took over mask verification and exhaustivity checks. This reduced the time to create a single training data point from over 2 minutes (human-only) to just 25 seconds, enabling massive scale.
Foundation models can't be trained for physics using existing literature because the data is too noisy and lacks published negative results. A physical lab is needed to generate clean data and capture the learning signal from failed experiments, which is a core thesis for Periodic Labs.
Instead of one component doing everything, SAM3 first uses a specialized token to answer a simple question: "Is this concept in the image at all?" Only then does it proceed to localization. This simplifies the model's task, improving its ability to avoid hallucinating objects that aren't there.
The breakthrough performance of Nano Banana wasn't just about massive datasets. The team emphasizes the importance of 'craft'—attention to detail, high-quality data curation, and numerous small design decisions. This human element of quality control is as crucial as model scale.
A critical learning at LinkedIn was that pointing an AI at an entire company drive for context results in poor performance and hallucinations. The team had to manually curate "golden examples" and specific knowledge bases to train agents effectively, as the AI couldn't discern quality on its own.
Fine-tuning an AI model is most effective when you use high-signal data. The best source for this is the set of difficult examples where your system consistently fails. The processes of error analysis and evaluation naturally curate this valuable dataset, making fine-tuning a logical and powerful next step after prompt engineering.
An OpenAI paper argues hallucinations stem from training systems that reward models for guessing answers. A model saying "I don't know" gets zero points, while a lucky guess gets points. The proposed fix is to penalize confident errors more harshly, effectively training for "humility" over bluffing.
A significant real-world challenge is that users have different mental models for the same visual concept (e.g., does "hand" include the arm?). Fine-tuning is therefore not just for learning new objects, but for aligning the model's understanding with a specific user's or domain's unique definition.
The team views its comprehensive 'SeiCo' benchmark, with over 200,000 concepts, as a more lasting contribution than the SAM3 model itself. While models are quickly surpassed, a robust benchmark can guide and measure progress for the entire research community for years.
The model uses separate components for detection and tracking. The detector needs an identity-agnostic representation (e.g., "dog"), while the tracker needs a unique representation for each instance (e.g., "this specific dog"). Decoupling these conflicting requirements was a key architectural breakthrough for video performance.