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Public story · 2026-07-27 · high
Feyn Labs added 6 blocks to BiRefNet's architecture and shipped both the 263M-parameter model and the open training library behind it.
Why now: Feyn Labs released FeyNoBg and NoBg on July 21.
FeyNoBg beat BiRefNet on four of eight background-removal benchmarks, per Feyn Labs' July 21 release of the model and its NoBg training library.
The wins aren't close calls. Feyn Labs reports S-measure scores of 0.981 vs 0.957 on UHRSD-TE and 0.983 vs 0.961 on HRSOD-TE. It also leads on DIS5K (0.961) and DAVIS-S (0.977). On the remaining four benchmarks, FeyNoBg trails by under 2%.
Under the hood, the change is simple: Feyn Labs added six blocks to the third feature-extractor stage of BiRefNet's 222M-parameter architecture, landing at 263M parameters.
Weights are public at feyninc/FeyNobg, and the training code that produced them is open at github.com/feyninc/nobg as the NoBg library. Anyone can pull the model, rerun the benchmark comparisons, or retrain it with different data instead of taking Feyn Labs' numbers on faith.
Adding 41M parameters bought four wins and four near-ties within 2%. That's a specific trade. The open NoBg library is what makes it checkable: pull the code, retrain it, and see whether the results hold outside Feyn Labs' own runs.
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Shared entity: July / Shared topic / Earlier coverage / Tension
Both cover July; overlapping topics (beat, benchmark); earlier July coverage from 2026-07-21.
Both cover July; overlapping topics (behind, benchmark); earlier July coverage from 2026-07-09.
Shared entity: July / Shared topic / Earlier coverage
Both cover July; overlapping topics (alongside, beat, benchmark); earlier July coverage from 2026-07-19.
Shared entities / Earlier coverage
Both cover July, Weights; earlier July coverage from 2026-07-26.
Both cover July, Small; earlier July coverage from 2026-07-25.
Shared entity: July / Earlier coverage / Tension / Downstream implication
Both cover July; earlier July coverage from 2026-07-22; pushes against this story (against).
Shared entities / Earlier coverage
Both cover July, Weights; earlier July coverage from 2026-07-21.
Both cover Small, Weights; earlier Small coverage from 2026-07-16.