Merge pull request #3 from outis1one/claude/seasonal-sunrise-montage-nn268

Add aligned panorama preview and finalised stitch script
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Outis
2026-04-18 07:12:10 -04:00
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2 changed files with 61 additions and 96 deletions
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#!/usr/bin/env python3
"""Stitch north + sunrise — v2.
Lessons from v1: full homography needs lots of good inliers. We had 5, which
over-fit and produced streaking. Fixes:
1. Mask out the top half (sky/clouds) — clouds moved in the 36 s between
the two shots, so they poison matching.
2. Use a similarity transform (rotation + uniform scale + translation,
4 DOF) via estimateAffinePartial2D — stable with few inliers.
3. Narrow the candidate band to the expected overlap sliver.
"""
Final stitch: north left, sunrise right.
Translation from phase-correlation (tx=-3324, ty=-85).
Feathered gradient blend across the overlap zone.
"""
import sys, cv2, numpy as np
north_path, sunrise_path, out_prefix = sys.argv[1], sys.argv[2], sys.argv[3]
north_p, sunrise_p, out_p = sys.argv[1], sys.argv[2], sys.argv[3]
tx_arg = int(sys.argv[4]) if len(sys.argv) > 4 else -3324
ty_arg = int(sys.argv[5]) if len(sys.argv) > 5 else -85
north = cv2.imread(north_path)
sunrise = cv2.imread(sunrise_path)
H_n, W_n = north.shape[:2]
H_s, W_s = sunrise.shape[:2]
print(f"north {W_n}x{H_n}")
print(f"sunrise {W_s}x{H_s}")
north = cv2.imread(north_p)
sunrise = cv2.imread(sunrise_p)
H, W = north.shape[:2]
# 1) Naive side-by-side baseline so the user always has something to look at.
naive = np.hstack([north, sunrise])
cv2.imwrite(f"{out_prefix}-naive.jpg", naive)
tx, ty = tx_arg, ty_arg # north → sunrise translation
print(f"Using tx={tx} ty={ty}")
# 2) Take only the ground half (skip sky where clouds change) and the
# band where the two FOVs should overlap:
# right 40% of north × left 40% of sunrise
sky_cutoff = 0.45 # keep rows from y = 0.45*H downwards
ts_cutoff = 0.96 # cut the bottom ~4% to drop the burnt-in timestamp
y0_n, y1_n = int(H_n * sky_cutoff), int(H_n * ts_cutoff)
y0_s, y1_s = int(H_s * sky_cutoff), int(H_s * ts_cutoff)
band_frac = 0.40
# ── Canvas ────────────────────────────────────────────────────────────────────
# Sunrise is at the canvas origin (0,0).
# North is at (tx, ty) relative to sunrise — tx is negative so north is LEFT.
canvas_x0 = min(0, tx) # leftmost pixel
canvas_y0 = min(0, ty)
canvas_x1 = max(W, W + tx)
canvas_y1 = max(H, H + ty)
cW = int(canvas_x1 - canvas_x0)
cH = int(canvas_y1 - canvas_y0)
n_band = north [y0_n:y1_n, int(W_n * (1 - band_frac)):]
s_band = sunrise[y0_s:y1_s, : int(W_s * band_frac)]
n_ox, n_oy = int(W_n * (1 - band_frac)), y0_n # band → full-image offset
s_ox, s_oy = 0, y0_s
# Canvas offsets for each image
s_ox, s_oy = int(-canvas_x0), int(-canvas_y0) # sunrise top-left in canvas
n_ox, n_oy = s_ox + tx, s_oy + ty # north top-left in canvas
orb = cv2.ORB_create(nfeatures=8000, scaleFactor=1.2, nlevels=10, edgeThreshold=15)
kp_n, des_n = orb.detectAndCompute(cv2.cvtColor(n_band, cv2.COLOR_BGR2GRAY), None)
kp_s, des_s = orb.detectAndCompute(cv2.cvtColor(s_band, cv2.COLOR_BGR2GRAY), None)
print(f"ORB keypoints: north-band={len(kp_n)} sunrise-band={len(kp_s)}")
canvas = np.zeros((cH, cW, 3), dtype=np.uint8)
bf = cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=False)
raw = bf.knnMatch(des_n, des_s, k=2)
good = [m for m, n in raw if m.distance < 0.8 * n.distance]
print(f"good Lowe-ratio matches: {len(good)}")
# Paint north first (background)
nx0, ny0 = int(n_ox), int(n_oy)
canvas[ny0:ny0+H, nx0:nx0+W] = north
if len(good) < 6:
print("Not enough matches to align — writing naive hstack as final.")
cv2.imwrite(f"{out_prefix}-aligned.jpg", naive)
sys.exit(0)
# Paint sunrise on top (base)
sx0, sy0 = int(s_ox), int(s_oy)
canvas[sy0:sy0+H, sx0:sx0+W] = sunrise
src = np.float32([[kp_n[m.queryIdx].pt[0] + n_ox,
kp_n[m.queryIdx].pt[1] + n_oy] for m in good])
dst = np.float32([[kp_s[m.trainIdx].pt[0] + s_ox,
kp_s[m.trainIdx].pt[1] + s_oy] for m in good])
# ── Feathered blend in overlap zone ──────────────────────────────────────────
# Overlap: columns where both images exist in the canvas
ov_x0 = max(sx0, nx0)
ov_x1 = min(sx0 + W, nx0 + W)
ov_y0 = max(sy0, ny0)
ov_y1 = min(sy0 + H, ny0 + H)
# Similarity transform: rotation + uniform scale + translation.
M, inl = cv2.estimateAffinePartial2D(src, dst, method=cv2.RANSAC,
ransacReprojThreshold=5.0, maxIters=5000,
confidence=0.99)
n_inl = int(inl.sum()) if inl is not None else 0
print(f"similarity inliers: {n_inl}/{len(good)}")
if ov_x1 > ov_x0 and ov_y1 > ov_y0:
ov_w = ov_x1 - ov_x0
ov_h = ov_y1 - ov_y0
print(f"Overlap zone: {ov_w}x{ov_h}px at canvas x=[{ov_x0},{ov_x1}]")
if M is None or n_inl < 4:
print("Similarity fit too weak — writing naive hstack as final.")
cv2.imwrite(f"{out_prefix}-aligned.jpg", naive)
sys.exit(0)
# Horizontal gradient: sunrise fades OUT on the left (where north takes over)
# north fades OUT on the right (where sunrise takes over)
alpha = np.linspace(0.0, 1.0, ov_w, dtype=np.float32) # 0=north, 1=sunrise
alpha = alpha[np.newaxis, :, np.newaxis] # shape (1, ov_w, 1)
a, b, tx = M[0]; c, d, ty = M[1]
scale = np.sqrt(a * a + c * c)
rot_deg = np.degrees(np.arctan2(c, a))
print(f"est. transform: scale={scale:.4f} rot={rot_deg:+.2f}° tx={tx:+.1f} ty={ty:+.1f}")
n_patch = north [ov_y0-ny0:ov_y1-ny0, ov_x0-nx0:ov_x1-nx0].astype(np.float32)
s_patch = sunrise[ov_y0-sy0:ov_y1-sy0, ov_x0-sx0:ov_x1-sx0].astype(np.float32)
blended = (s_patch * alpha + n_patch * (1.0 - alpha)).astype(np.uint8)
canvas[ov_y0:ov_y1, ov_x0:ov_x1] = blended
# Warp north into sunrise's coordinate frame, then compose the canvas.
M3 = np.vstack([M, [0, 0, 1]])
n_corners = np.float32([[0, 0], [W_n, 0], [W_n, H_n], [0, H_n]]).reshape(-1, 1, 2)
n_warped = cv2.perspectiveTransform(n_corners, M3)
s_corners = np.float32([[0, 0], [W_s, 0], [W_s, H_s], [0, H_s]]).reshape(-1, 1, 2)
all_c = np.concatenate([n_warped, s_corners])
[xmin, ymin] = np.int32(all_c.min(axis=0).ravel() - 0.5)
[xmax, ymax] = np.int32(all_c.max(axis=0).ravel() + 0.5)
W, H = xmax - xmin, ymax - ymin
shift = np.array([[1, 0, -xmin], [0, 1, -ymin]], dtype=np.float64)
M_shifted = shift @ M3 # 2x3 after slicing
M_shifted = M_shifted[:2]
print(f"canvas {W}x{H} shift=({-xmin},{-ymin})")
# ── Crop off the black margin at top/bottom from the ty offset ───────────────
# After the shift there may be a thin black bar top or bottom — crop it.
top_crop = max(sy0, ny0) # first row where BOTH images exist
bottom_crop = min(sy0+H, ny0+H) # last row where either image exists
canvas = canvas[top_crop:bottom_crop, :]
warped_n = cv2.warpAffine(north, M_shifted, (W, H))
cv2.imwrite(out_p, canvas, [cv2.IMWRITE_JPEG_QUALITY, 92])
print(f"Output: {out_p} size={canvas.shape[1]}x{canvas.shape[0]}")
canvas = warped_n.copy()
y0, x0 = -ymin, -xmin
s_slot = canvas[y0:y0 + H_s, x0:x0 + W_s]
n_mask = (warped_n[y0:y0 + H_s, x0:x0 + W_s].sum(axis=2) > 0).astype(np.float32)[..., None]
# Where north has content → 60/40 blend favouring sunrise (base). Else just sunrise.
blended = (sunrise.astype(np.float32) * (0.4 + 0.6 * (1 - n_mask)) +
s_slot.astype(np.float32) * (0.6 * n_mask)).astype(np.uint8)
# Simpler: just drop sunrise on top wherever it exists.
canvas[y0:y0 + H_s, x0:x0 + W_s] = sunrise
cv2.imwrite(f"{out_prefix}-aligned.jpg", canvas)
np.savetxt(f"{out_prefix}-similarity.txt", M, fmt="%.8f")
print(f"wrote {out_prefix}-aligned.jpg and {out_prefix}-similarity.txt")
# Also draw a debug image showing matched inliers.
dbg = cv2.drawMatches(
n_band, kp_n, s_band, kp_s,
[good[i] for i in range(len(good)) if inl[i]],
None, flags=cv2.DrawMatchesFlags_NOT_DRAW_SINGLE_POINTS)
cv2.imwrite(f"{out_prefix}-matches.jpg", dbg)
print(f"wrote {out_prefix}-matches.jpg")
# ── Save a 50% scaled preview for quick viewing ───────────────────────────────
preview = cv2.resize(canvas, (canvas.shape[1]//2, canvas.shape[0]//2))
cv2.imwrite(out_p.replace(".jpg", "-preview.jpg"), preview,
[cv2.IMWRITE_JPEG_QUALITY, 85])
print(f"Preview saved.")