photon_sample — PHOTON `counting` op

• 資料種類:image2d → image2d

• 呼叫:import photoncount; photoncount.photon_sample(image, photons_per_unit=100.0, dark_rate=0.0, seed=0)(或 opsphoton.get("photon_sample"))

用法

把期望光子數影像做卜瓦松取樣,得到實際的光子計數影像。

> 以下的詳細說明為原文 —— 摘要與標題已翻譯。

*image* is a non-negative 2-D map of scene radiance in arbitrary units;

`lambda = image * photons_per_unit + dark_rate` is the expected number of

photons in each pixel over the exposure, and the result is one Poisson

realisation of it. *dark_rate* is the dark-count contribution (a SPAD counts

thermally generated carriers even in the dark) in the same photon units.

Returns the counts themselves as a float64 `(H, W)` image (integer

valued). That is the deliberate difference from

:func:backends_aug.aug_shot_noise, which returns `Poisson(v*K)/K` clipped

to `[0, 1]` for training-data augmentation: every operator downstream here

(Fano factor, Anscombe, Coates, dToF) needs `N`, and the rescale-and-clip

is not invertible.

`seed` is a required non-negative integer and the RNG is

`numpy.random.default_rng(seed)` — same seed, same frame, on any machine.

Ground truth it reproduces (pinned in `tests/test_photoncount.py`): the

sample mean and sample variance both converge to `lambda`. Measured on a

flat `lambda = 100` field of 512x512 pixels at seed 0 — mean 99.9796,

Fano factor 1.001089, so the photon-limited SNR is `sqrt(lambda)`: 9.9990

predicted from the mean, 9.9935 actually achieved.

Raises `ValueError`: negative or non-finite *image*, negative

*photons_per_unit* / *dark_rate*, a non-integer or negative *seed*, an image

over :data:MAX_IMAGE_ELEMENTS, and — instead of letting numpy fail deep

inside the sampler — any `lambda over :data:MAX_LAMBDA`.

詳細使用指南

• photon_timeresolved 族使用指南

參考(範例資料・文獻)

• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。

• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。

• 演算法的正典(作者・年份)與用途見上面的族使用指南。

可執行的範例(實際呼叫該運算子並已驗證的樣例)

• photon_timeresolved — py -3.11 examples/photon_timeresolved.py

型別可銜接的下一個運算子(可接受 `image2d` 作為輸入)

photon_statistics · photon_uncertainty · anscombe_transform · anscombe_inverse

同類別(`counting`)

photon_statistics · photon_uncertainty

*Provenance: photoncount.py — PHOTON 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*

photon_sample — PHOTON counting op

用法