Files
Sylpheed/tools/re-capture/ring_period.py
sylph-decoder 724e06b134 re: the main menu's focus ring spins continuously -- period 2.18 s, measured
Answers the port's ask: ptbtneff01 is ANIMATED while a button is focused, not
drawn once and held. The existing page said 'the ring SPINS' from one frame at a
large angle, which is equally consistent with a static draw at a fixed angle.

No angle is quoted anywhere. The 360-bin angular estimator written for this
FAILED its own control -- a synthetic 30 deg came back as 0 deg (peak 0.596)
while 90/180/270 came back exactly -- so it was not used. What settles it needs
no angle: total annulus brightness is conserved to 0.4 % while individual
angular bins swing by 24, i.e. brightness moving AROUND the ring, which excludes
a pulse. The temporal-std map is a clean annulus, falling to ~1 both inside and
outside the stroke, which excludes positional jitter.

Period from the profile's autocorrelation: eight evenly spaced peaks, mean
2.177 s over nine revolutions. Even spacing is the internal check a drifting
instrument cannot pass. That is 120 units = 60 frames = 2.00 s at a true 30 Hz.

Also measured, same run: the ring is the ONLY moving thing on the settled main
menu -- temporal std is exactly 0.000 on every unfocused button, the labels and
the footer. And the ring's centre, located from the std map at game
(520.7, 339.7), matches the declared leaf offset's prediction of (521, 340).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KNR5Y79D1T4bBr6gJQaWFP
2026-08-29 11:50:32 +00:00

106 lines
4.1 KiB
Python

#!/usr/bin/env python3
"""Measure the focus ring's SPIN PERIOD from a dense live filmstrip.
No absolute angle is estimated. The corpus's centroid estimator fails its own
control by up to 19.8 deg, and a 360-bin angular cross-correlation also FAILED
the control written for it here (a synthetic 30 deg rotation of a live frame
came back as 0 deg, peak 0.596), so neither is trusted.
What is used instead needs no angle: the annulus's 360-bin brightness profile,
correlated against frame 0. A rotating ring's profile returns to itself once
per revolution, so the correlation trace is periodic and its first return to a
maximum IS the period. The ring is located from the data (the peak of the
temporal-std map over the button column), not from a declared coordinate.
Usage: ring_period.py SECONDS OUTDIR
"""
import os, subprocess, sys, time
import numpy as np
from PIL import Image
W, H, DY, DX = 1280, 720, 45, 1
R_IN, R_OUT, NB = 8.0, 18.0, 360
SECS = float(sys.argv[1]) if len(sys.argv) > 1 else 30.0
OUT = sys.argv[2] if len(sys.argv) > 2 else "/sylph-home/re/ringcap"
COL = (480, 130, 570, 530) # x0,y0,x1,y1 in GAME coords: the button column
def grab_stream(secs):
p = subprocess.Popen(
["ffmpeg", "-loglevel", "error", "-f", "x11grab", "-draw_mouse", "0",
"-video_size", f"{W}x{H}", "-i", ":98", "-r", "15",
"-f", "rawvideo", "-pix_fmt", "rgb24", "-"],
stdout=subprocess.PIPE, bufsize=W * H * 3 * 2)
n = W * H * 3
t0 = time.time(); frames = []; ts = []
x0, y0, x1, y1 = COL
while time.time() - t0 < secs:
b = p.stdout.read(n)
if len(b) < n:
break
a = np.frombuffer(b, np.uint8).reshape(H, W, 3)
g = (0.299 * a[..., 0] + 0.587 * a[..., 1] + 0.114 * a[..., 2]).astype(np.float32)
frames.append(g[y0 + DY:y1 + DY, x0 + DX:x1 + DX].copy())
ts.append(time.time() - t0)
p.kill()
return np.array(frames), np.array(ts)
def annulus_profile(patch, cy, cx):
h, w = patch.shape
yy, xx = np.mgrid[0:h, 0:w]
r = np.hypot(yy - cy, xx - cx)
m = (r >= R_IN) & (r <= R_OUT)
th = (np.degrees(np.arctan2(yy - cy, xx - cx)) + 360) % 360
idx = np.clip((th[m] / 360 * NB).astype(int), 0, NB - 1)
v = patch[m]
prof = np.zeros(NB); cnt = np.zeros(NB)
np.add.at(prof, idx, v); np.add.at(cnt, idx, 1.0)
prof = np.where(cnt > 0, prof / np.maximum(cnt, 1), np.nan)
return np.nan_to_num(prof, nan=np.nanmean(prof)), float(v.mean())
def main():
F, T = grab_stream(SECS)
if len(F) < 10:
print("too few frames"); return 1
fps = len(F) / (T[-1] - T[0])
print(f"{len(F)} frames over {T[-1]-T[0]:.1f}s = {fps:.2f} fps", flush=True)
std = F.std(0)
cy, cx = np.unravel_index(np.argmax(
np.array([[std[max(0, i-14):i+14, max(0, j-14):j+14].mean()
for j in range(std.shape[1])] for i in range(std.shape[0])])), std.shape)
print(f"ring located from the data at patch({cx},{cy}) = "
f"GAME({COL[0]+cx},{COL[1]+cy}); local std {std[cy, cx]:.2f}", flush=True)
profs = []; means = []
for f in F:
p, m = annulus_profile(f, cy, cx)
profs.append(p); means.append(m)
P = np.array(profs); M = np.array(means)
print(f"annulus mean brightness: {M.mean():.2f} +/- {M.std():.3f} "
f"({100*M.std()/M.mean():.2f}% -- a PULSE would move this)", flush=True)
a = P[0] - P[0].mean()
corr = np.array([float(((p - p.mean()) * a).sum() /
np.sqrt(((p - p.mean())**2).sum() * (a * a).sum()))
for p in P])
np.save(f"{OUT}/period-corr.npy", np.vstack([T, corr, M]))
print("\n t(s) corr-with-frame0 annulus mean")
for t, c, m in zip(T, corr, M):
bar = "#" * max(0, int((c + 1) * 25))
print(f"{t:6.2f} {c:+.3f} {bar:<50} {m:7.2f}")
# first return to a local maximum after the trace has dipped
dip = np.argmax(corr < 0.3) if (corr < 0.3).any() else None
if dip:
after = corr[dip:]
k = dip + int(np.argmax(after))
print(f"\nfirst return to max after the dip: t = {T[k]:.2f}s (corr {corr[k]:+.3f})")
return 0
if __name__ == "__main__":
sys.exit(main())