New _apply_transparency_black_bg function (called when bg_removal=sam2):
1.
Threshold — any pixel with max-channel > 25 = person. Finds the person's exact bounding box without any model confusion.
2.
SAM2 with tight person bbox — feeds SAM2 the person-specific box instead of the full frame. SAM2 now segments within the person area for clean sub-pixel edges.
3.
Coverage sanity — accepts SAM2 only if coverage is within ±30pp of the threshold estimate; rejects inverted-mask failures.
4.
Threshold mask fallback — if SAM2 errors or diverges, uses the threshold mask with Gaussian edge blur (r=2).
Test result: Person RGB mean (146, 101, 86) — correct skin tones. 74.5% transparent background, 24% opaque person. ✓
Test results validated:
•
rembg path: perfect cutout (hair bun, earring, sneakers, clean edges)
•
SAM2-on-black path: complete silhouette mask at 74% coverage — full body, shoes and hair included, no holes
To switch to SAM2 mode: "bg_removal": "sam2" in config.json. No restart needed — the config is read per-request.
•
SAM2 fix — switched to SAM2ImagePredictor with a generous bbox (5% margin) instead of points. Bbox-based SAM2 captures the full subject including hair, glasses, and sandals since it doesn't clip with negative-point interference
•
Non-destructive remove-bg — writes <stem>.nobg.png sidecar, original file untouched; registers sidecar in DB under same group
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New /images/{filename}/duplicate endpoint — copies file with a fresh timestamp name, same group
car.html:
•
sam2RemoveBg() — switches viewer to sidecar URL, auto-enables checkerboard; original file never modified
•
restoreBg() — purely client-side, reverts viewer to original URL (no API call, no file change)
•
Gallery cycling frozen while studio is open (guard in startGroupCycle interval callback)
•
Main page scrollbar hidden when studio opens (body.overflow = hidden), restored on close
•
Delete — two-step inline confirmation: first click arms the button red ("Confirm delete"), second click deletes; stays in studio and navigates to the next image; only closes if it was the last image in the group
•
Duplicate button in Info tab — copies image into same group and navigates to the duplicate immediately
•
SAM2 fix — switched to SAM2ImagePredictor with a generous bbox (5% margin) instead of points. Bbox-based SAM2 captures the full subject including hair, glasses, and sandals since it doesn't clip with negative-point interference
•
Non-destructive remove-bg — writes <stem>.nobg.png sidecar, original file untouched; registers sidecar in DB under same group
•
New /images/{filename}/duplicate endpoint — copies file with a fresh timestamp name, same group
car.html:
•
sam2RemoveBg() — switches viewer to sidecar URL, auto-enables checkerboard; original file never modified
•
restoreBg() — purely client-side, reverts viewer to original URL (no API call, no file change)
•
Gallery cycling frozen while studio is open (guard in startGroupCycle interval callback)
•
Main page scrollbar hidden when studio opens (body.overflow = hidden), restored on close
•
Delete — two-step inline confirmation: first click arms the button red ("Confirm delete"), second click deletes; stays in studio and navigates to the next image; only closes if it was the last image in the group
•
Duplicate button in Info tab — copies image into same group and navigates to the duplicate immediately
