SPP1,204 / 6,000
VAR0.0031
FIREFLY@ 812,204
so the estimator is unbiased — wrong on every frame, right on average.
- Think of one pixel. Light reaches it along infinitely many paths.
- We can't integrate that. So we guess — randomly.
- Each guess is wrong. But the errors cancel on average.
- That's what unbiased means: wrong on every frame, right on average.
- Now the catch: how fast does the average settle?
- Variance drops as 1/N. Noise, its square root, as 1/√N.
- Halve the noise → four times the samples.
- Which is why every renderer ships a denoiser.
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04:1212:40ch 2 · the estimator♪ ▮▮▮▯