typed op• Data kinds: video → video
• Call: fullseye.apply(img, "tb_background_subtraction_window", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ tb_background_subtraction_window: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ tb_background_subtraction_window: knob b sweep (docs site)
Stages (the ops that come before → this op, left to right):
▸ tb_background_subtraction_window: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ tb_background_subtraction_window: other inputs (docs site)
Motion (GIF: frames / views / slices in turn. The still figure is the complete one; the GIF is supplementary):
Causal window-median background → per-frame 0/1 foreground masks `(T, H, W) (video`).
> The detailed description below is the original text — the summary and the headings are translated.
フレーム `t ごとに、直近 window 枚(max(0, t-window+1) .. t`、**そのフレーム
自身を含む**)の画素ごとの中央値を背景 `bg とし、|frame_t - bg| > threshold`
を 1、それ以外を 0 にする。未来のフレームは見ない(因果的)ので、先頭では
枚数が足りないぶん窓が短い。
• `video: (T, H, W)` の配列、または同形・同 dtype の 2-D フレームの list。
uint8/uint16 は dtype の最大値で `[0, 1] に、float はそのまま [0, 1]` に
クリップ。カラー `(T, H, W, C) は受けない。NaN/Inf は ValueError`。
• `window`: 1〜4096 の int(bool 不可)。1 だと背景 = 自分なので全画素 0。
偶数枚のときの中央値は中間 2 値の平均。
• `threshold: [0, 1] の強度単位(uint8 なら /255` 換算)。
• 返り値: `(T, H, W)` float64 の 0 / 1。
• 失敗: `ValueError`(形・dtype・範囲・非有限)。
ゆっくり動く物体は `window` 枚以内に背景へ溶けるので、その場合は
`running_gaussian_foreground(選択的更新)か exponential_foreground` を。
背景そのものが要るなら `temporal_median_window`。
2-D 進化レジストリへ橋渡しした videostream の op `background_subtraction_window。実装は同じで、呼び出し規約だけ op(v, a, b) に合わせてある。a が window(既定 5)、b が threshold`(既定 0.1)を振る。
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.
img_to_video 0.50 0.50 tb_background_subtraction_window 0.50 0.50
▸ Load this pipeline · Load & run
The examples below call the underlying ledger op background_subtraction_window. This bridge op is the same implementation adapted to the fn(v, a, b) convention, so the behaviour carries over unchanged (only the call form differs).
• video_streaming — py -3.11 examples/video_streaming.py
video as input)identity · tb_temporal_bandpass · tb_temporal_band_power · tb_temporal_median_window · tb_moving_average_window · tb_frame_difference_causal · tb_exponential_background · tb_exponential_foreground
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 operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.