process opbeatcube → beatcubeimport fullseye as fs; fs.ledger.fmcw_window_apply(cube, window='hann', axis='range') (実装を直接呼ぶなら import rangedoppler; rangedoppler.fmcw_window_apply(cube, window='hann', axis='range')、台帳から引くなら opsrangedoppler.get("fmcw_window_apply"))Apply a periodic window along the range and/or Doppler axis of a beat cube.
The sidelobes of a rectangular (unwindowed) transform are -13.3 dB, so a strong target buries a weak one 20 dB down at a completely different range. Windowing trades main-lobe width for sidelobe level; the published figures (Harris 1978, Table 1) and the levels measured in this repository on a single bin-centred target are:
========== ============== ============== ================== window published PSL measured PSL measured -3 dB lobe ========== ============== ============== ================== rect -13.3 dB -13.25 dB 0.885 bin hann -31.5 dB -31.47 dB 1.438 bin hamming -42.7 dB -42.45 dB 1.301 bin blackman -58.1 dB -58.11 dB 1.641 bin ========== ============== ============== ==================
Measured by transforming each window on its own with 2^18-point zero padding and taking the highest lobe past the first null — that is the definition of peak sidelobe level, so these are the module’s own numbers, not copied ones. Hamming lands 0.25 dB off the published figure because the published one is for the optimal 0.53836/0.46164 pair; the 0.54/0.46 coefficients written here are the textbook ones and this is what they actually give.
What it buys, measured end to end: a target 45 dB below a strong one, seven
range bins away, is undetectable unwindowed (its cell sits 24.6 dB down
in the leakage skirt and is not even a local maximum) and becomes a clean
local maximum at -43.6 dB with hann. That comparison is step 4 of
examples/fmcw_range_doppler.py.
axis is named by role — "range" (fast time, the last axis),
"doppler" (slow time, the middle axis) or "both" — never by number,
because a transposed cube is the mistake this naming is defending against.
The window is not folded into :func:range_doppler_map: keeping it a
separate op is what lets the sidelobe table above be measured as a
difference, and keeps the transform op a pure 2-D FFT.
Returns a new complex cube of the same shape. Raises ValueError on a
real-valued or malformed cube, or an unknown window / axis.
py -3.11 examples/fmcw_range_doppler.pybeatcube を入力に取れる)range_doppler_map · fmcw_range_profile · beamform_delay_sum · beamform_doa
process)range_doppler_map · range_doppler_peaks · fmcw_range_profile
Provenance: rangedoppler.py — RANGEDOPPLER operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.