MultiMatte turns SAM 3 into promptable background removal by fine-tuning 2.27 percent of its weights
Feyn Labs·medium signal
Feyn Labs published MultiMatte on 2026-09-10. It keeps whatever a text phrase names ("the dog") and removes the rest, built by low-rank fine-tuning 19.49M of SAM 3's 860M parameters. It reports an S-measure of 0.901 on DIS-VD versus 0.667 for stock SAM 3, and 0.979 on the unseen DAVIS-S split. It ships as `pip install nobg`, with weights on Hugging Face. The benchmarks are the authors' own and the Show HN had 49 points.