tb_beamform_delay_sum — 2D typed op

Datenarten: beatcubesignal

Aufruf: fullseye.apply(img, "tb_beamform_delay_sum", a=0.5, b=0.5) (das 2-D-Modell ist ein Bild plus zwei skalare Regler a,b∈[0,1])

Verwendung

Delay-and-Sum-(Bartlett-)Winkelspektrum für eine Range-Doppler-Zelle.

> Die ausführliche Beschreibung unten ist der Originaltext — Zusammenfassung und Überschriften sind übersetzt.

Takes the per-antenna complex value at a single range-Doppler cell — by

default the strongest one — and for each steering angle removes the expected

inter-element phase and sums:

`P(theta) = |sum_k conj(exp(1j*2*pi*d*k*sin(theta)/lambda)) * x_k|^2`

which peaks at the true arrival angle with value `(N_a * |a|)^2`: the

aperture gives `N_a in amplitude, N_a^2` in power. That is the exact

ground truth the tests pin. Measured with 8 elements: the peak power is

bit-exactly `(N_a*N_c*N_s)^2 = 268435456` (relative error 0.0), and

sweeping the true angle from -80 to +80 degrees in 5-degree steps (33 cases)

the reported angle matches the truth with a maximum error of 0.0 degrees.

The steering grid defaults to `arange(-90, 90.5, 1.0). normalize=True`

divides by `N_a^2 * N_c^2 * N_s^2` so that a unit-amplitude bin-centred

target peaks at 1.0.

Returns a 1-D float64 array of powers, one per grid angle — a plain signal,

so :mod:dsp's `find_peaks and :mod:funct1d`'s smoothing apply to it.

Use :func:beamform_doa if you want the angles themselves.

*range_bin* is a plain `0..N_s-1` index; *doppler_bin* is the signed

velocity bin, the same convention :func:range_doppler_peaks reports, so a

detection can be handed straight back in. Both or neither — half a cell

address raises rather than quietly beamforming the strongest cell instead.

Raises `ValueError`: no aperture — either a single element, or many

elements packed into under ~0.28 wavelengths. In both cases the spectrum is

flat to within float noise and `argmax` returns the first grid angle, i.e.

a confident report of -90 degrees that is pure tie-breaking (measured: 8

elements at 1e-12 m spacing gave a peak-to-trough spread of exactly 0.0 and

reported -90.0). Also: an all-zero cube or an all-zero selected cell; only

one of *range_bin* / *doppler_bin*; an out-of-bounds bin index; an angle grid

outside `[-90, 90]`; an FFT that overflows to NaN; plus the usual cube and

scalar refusals.

Typed bridge of the rangedoppler op `beamform_delay_sum into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. a drives wavelength_m (default 0.0038934); b` is unused.

Referenzen (Beispieldaten, Literatur)

• Katalog der Beispieldaten (Download-URLs / Lizenzen) — 2-D nutzt skimage.data (BSD/Public Domain) plus synthetische Bilder, 3-D nennt Download-URLs echter Datenquellen (Stanford, PDS, …).

• Herkunft und Literatur der Operatoren — die Quellen der Forschung/Verfahren, auf denen diese Operatorfamilie beruht.

Ausführbare Beispiele (verifizierte Samples, die diesen Operator wirklich aufrufen)

• (noch keine)

Typkompatible Folge-Operatoren (nehmen signal als Eingabe)

identity · tb_create_funct_1d_array · tb_smooth_funct_1d_gauss · tb_smooth_funct_1d_mean · tb_derivate_funct_1d · tb_integrate_funct_1d · tb_zero_crossings_funct_1d · tb_abs_funct_1d

Gleiche Kategorie (typed)

tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_angle_3points · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal


*Provenance: ops.py — 2D Operator-Registry. Diese Notiz wird von tools/opdocs.py md erzeugt (nicht von Hand bearbeiten).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.