typed op• 資料種類:counts → counts
• 呼叫:fullseye.apply(img, "tb_tcspc_background_subtract", a=0.5, b=0.5)(2-D 的模型是一張圖 + 兩個純量旋鈕 a,b∈[0,1])
*圖為在 128×128 合成輸入上實際執行的輸出。左為輸入，右為輸出。點雲以俯視散點顯示(亮度 = z)，一維序列為折線，體資料為沿 z 的最大值投影，影片為中間影格，複數影像為振幅；無法成像的回傳值直接顯示數值。*
*旋鈕 a 不改變輸出(實測: 0.1 / 0.5 / 0.9 相同)。*
掃描旋鈕 b(0.1 / 0.5 / 0.9，另一旋鈕取預設):
▸ tb_tcspc_background_subtract: knob b sweep (docs site)
階段(前置運算子 → 本運算子，由左至右):
▸ tb_tcspc_background_subtract: stages (docs site)
換別的影像(合成場景 / 照片 / 硬幣。上排為輸入，下排為對應輸出。旋鈕取預設):
▸ tb_tcspc_background_subtract: other inputs (docs site)
從到達時間直方圖中去除環境光/暗計數本底。
> 以下的詳細說明為原文 —— 摘要與標題已翻譯。
Outdoors, most of what a dToF sensor counts is sunlight: a roughly uniform
pedestal under the return pulse. It biases the centroid toward the middle of
the window (a floor of `b` per bin pulls the first moment toward
`window/2`) and it inflates the apparent signal, so it is removed before
any depth or lifetime estimate.
The level is estimated by *method* and then subtracted (the sign trap:
the result is `hist - level, clipped at 0, never hist + level`):
• `"median"` (default) — the median of every bin. Robust while the pulse
occupies well under half the window, which is the normal dToF case.
• `"leading"` — the mean of the first *leading_bins* bins, the classical
choice when the pulse is known to arrive late (a far target).
• `"trailing"` — the mean of the last *leading_bins* bins, for
fluorescence decays where the tail is background.
• `"quantile"` — the given *quantile* of all bins, for tuning by hand.
*leading_bins* defaults to `None = min(8, len(hist))`, so the default
call works on a short histogram instead of raising over a constant nobody
chose (a fixed default of 8 made `method="leading"` fail on any histogram
with fewer than 8 bins).
*scale* multiplies the estimated level before subtraction (`scale=1.2` for
a deliberately aggressive removal). Clipping at 0 means the result is a valid
non-negative histogram that the rest of this module will accept.
Ground truth: on a noiseless histogram with a known flat pedestal of 20
counts/bin under a 5000-photon pulse covering 5.1% of the window, the median
estimate recovers 20.000000 and the returned histogram equals the pedestal-
free pulse exactly (measured area error 0.0, pinned in the tests).
Returns a float64 1-D histogram of the same length as *hist*.
Raises `ValueError`: negative, non-finite or non-1-D *hist*, an unknown
*method*, a *leading_bins* outside `[1, len(hist)]`, a *quantile* outside
`[0, 1]`, and a negative *scale*.
Typed bridge of the photon op `tcspc_background_subtract into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. a drives quantile (default 0.5) and b drives scale` (default 1).
• 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。
下面的程式已確認可以執行(與圖相同的輸入)。在 Studio 說明中，此區塊會變成按鈕，可當場載入並執行。
img_to_counts 0.50 0.50 tb_tcspc_background_subtract 0.50 0.50
▸ Load this pipeline · Load & run
下面的範例呼叫的是底層帳本運算子 tcspc_background_subtract。此橋接運算子只是把同一實作適配為 fn(v, a, b) 慣例，行為完全相同(只是呼叫形式不同)。
• photon_timeresolved — py -3.11 examples/photon_timeresolved.py
• poc_dtof_ranging — py -3.11 examples/poc_dtof_ranging.py
counts 作為輸入)identity · tb_spad_deadtime_apply · tb_spad_deadtime_correct · tb_tcspc_coates_correct · tb_tcspc_irf_convolve · tb_dtof_depth · tb_countrate_to_counts · tb_counts_to_countrate
typed)tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample
*Provenance: ops.py — 2D 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.