lhk229
5ddf0cd392
Green spill bleeds into pixels ViTMatte marks as solid foreground (alpha~1), but despill was gated to the soft edge band (0.005<alpha<0.995) and weakened exactly there: the alpha tent peaked at 0.5 and bg_confidence (low on the character edge) further suppressed the correction. - (1) Apply despill to the whole foreground (alpha > edge_low) instead of the soft band only; neutral pixels stay untouched via the green-excess term. - (2) Weight by alpha at full strength across the opaque range (alpha>=0.5), easing off only where mostly transparent, instead of a tent peaking at 0.5. - (3) Drop bg_confidence as a despill gate; localise purely by green excess. Controlled comparison (same alpha, only despill changed), edge_green_excess: ViTMatte TestImage p95 0.239->0.176, mean 0.131->0.061 ViTMatte TestImage2 p95 0.231->0.165, mean 0.115->0.052 Removes now-unused DespillSettings fields edge_high and bg_confidence_weight. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
BgFilter
Offline green screen character matting for AI-generated character images.
The first implementation follows the workflow in
docs/green_screen_matting_workflow.md:
RGB input -> chroma confidence -> trimap -> ViTMatte -> alpha cleanup -> despill -> RGBA PNG -> QA previews
Environment
Use the conda environment lightML.
conda activate lightML
pip install -r requirements.txt
If the shell is not activated, call the environment Python directly:
D:\MiniConda\envs\lightML\python.exe -m bgfilter.cli --help
Single Image
D:\MiniConda\envs\lightML\python.exe -m bgfilter.cli `
--input Samples\TestImage.png `
--output Outputs\TestImage_rgba.png `
--debug-dir Outputs\TestImage_debug `
--config configs\default.yaml `
--device cuda
The CLI reads configs/default.yaml when --config is provided. Command-line
options override config values, so tuning can usually happen in YAML while
runtime choices such as --device cpu stay on the command line.
Use CPU for validation when CUDA is unavailable:
D:\MiniConda\envs\lightML\python.exe -m bgfilter.cli `
--input Samples\TestImage.png `
--output Outputs\TestImage_rgba.png `
--debug-dir Outputs\TestImage_debug `
--config configs\default.yaml `
--device cpu
Batch
D:\MiniConda\envs\lightML\python.exe -m bgfilter.cli `
--input-dir Samples `
--output-dir Outputs `
--debug-dir Outputs\debug `
--config configs\default.yaml `
--device cuda
Chroma-Only Debug Mode
This mode skips ViTMatte and uses chroma confidence as an alpha seed. It is useful for fast debugging of chroma confidence, trimap, despill, and QA outputs.
D:\MiniConda\envs\lightML\python.exe -m bgfilter.cli `
--input-dir Samples `
--output-dir Outputs\chroma `
--debug-dir Outputs\chroma_debug `
--config configs\default.yaml `
--matting-method chroma `
--device cpu
Outputs
For each processed image, the CLI writes an RGBA PNG and optional debug files:
bg_confidence.png
trimap.png
alpha.png
foreground_mask.png
foreground_unmix_mask.png
foreground_local_mask.png
foreground_rgb.png
despill_mask.png
preview_black.png
preview_white.png
preview_gray.png
preview_red.png
preview_blue.png
qa_grid.png
metadata.json
Quality Check
The quality checker measures alpha validity and green spill on semi-transparent edge pixels.
D:\MiniConda\envs\lightML\python.exe -m bgfilter.quality_cli `
Outputs\TestImage_rgba.png `
--max-edge-green-excess-p95 0.30
Run the bundled sample smoke check:
D:\MiniConda\envs\lightML\python.exe scripts\smoke_samples.py `
--samples-dir Samples `
--output-dir Outputs\smoke_samples `
--config configs\default.yaml `
--device cpu `
--fallback-to-chroma-alpha `
--max-edge-green-excess-p95 0.30
Current Notes
Samples/andOutputs/are ignored by Git.ViTMattemodel weights are loaded from Hugging Face on first use.- Foreground color estimation runs before final de-spill and writes debug masks for unmixing and local foreground propagation.