three_frame_difference — VIDEOSTREAM `motion` op

• Data kinds: video → video

• Call: import videostream; videostream.three_frame_difference(video, threshold: 'float' = 0.1) -> 'np.ndarray' (or opsvideostream.get("three_frame_difference"))

Usage

Collins three-frame-difference motion mask per frame → 0/1 `(T, H, W) (video`).

`(|f_t−f_{t−1}|>T) AND (|f_{t−1}−f_{t−2}|>T)`; zeros for the first two

frames. Ghost-free compared with :func:frame_difference_causal.

Detailed usage guide

• video_streaming family guide

Background guides (the physics and conventions behind this op)

• mv_cables — ケーブル（規格・速度・給電・ロボットケーブル）

• mv_frame_grabbers — フレームグラバーボード（光学系ではないが、撮れるかを決める）

• mv_standards — カメラインターフェースの規格と団体

References (sample data, literature)

• 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 canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• video_streaming — py -3.11 examples/video_streaming.py

Ops the type connects to (they accept `video` as input)

temporal_median_window · moving_average_window · background_subtraction_window · frame_difference_causal · exponential_background · exponential_foreground · running_mean_std · optical_flow_magnitude_stream

Same category (`motion`)

motion_history_image · motion_energy_image

*Provenance: videostream.py — VIDEOSTREAM operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

three_frame_difference — VIDEOSTREAM motion op