# ComfyUI-AutoMask - [**README (Japanese)**](README_JP.md) - **Guide (External site)**: [English](https://www.ai-image-journey.com/2026/08/birefnet-depthanythingv3-sam31-lama.html) | [Japanese](https://note.com/ai_image_journey/n/nf45afca51b00) Custom nodes for ComfyUI that automatically refine and threshold masks — no manual trial-and-error with black/white points or fixed cutoff values. ## Nodes ### Mask Refine

**BiRefNet**

**BiRefNet -> Mask Threshold = 0.01 -> Mask Refine**

Refines a rough mask into a soft alpha matte using closed-form matting ([`pymatting`](https://github.com/pymatting/pymatting)), guided by the source image. > This node is a simplified implementation based on the **Image Matting** node from [ComfyUI-Image-Filters](https://github.com/spacepxl/ComfyUI-Image-Filters) by [spacepxl](https://github.com/spacepxl), with `preblur` kept as the only exposed setting. - **Inputs** - `image` — `IMAGE`, the source image the mask was drawn on - `mask` — `MASK`, the rough/binary mask to refine - `preblur` — `INT` (default `10`), Gaussian blur radius applied to the mask before it's converted into a trimap. Higher values soften hard mask edges before matting; `0` disables preblurring. - **Output**: `MASK` — a refined, soft alpha matte Use this after any rough segmentation (SAM 3.1, BiRefNet, manual paint, threshold, etc.) to get cleaner edges, especially around hair, fur, or semi-transparent regions. ### Auto Mask Threshold

Analyzes a soft mask's value histogram and automatically finds meaningful threshold boundaries (valleys between peaks) instead of requiring a manually chosen cutoff. - **Inputs** - `mask` — `MASK`, a soft (non-binary) mask, e.g. the output of Auto Mask Refine - `threshold` — `INT` (default `5`, range `1`–`8`), selects the n-th detected boundary (ascending) for the single-mask output - **Outputs** - `mask_batch (x8)` — `MASK`, a batch of up to 8 binary masks, one per detected boundary - `mask` — `MASK`, the single binary mask selected by `threshold` - `histogram` — `IMAGE`, a rendered histogram showing the detected peaks/valleys and which one was selected (also shown in the node preview) Internally the node finds up to 5 valleys between histogram peaks plus up to 3 minor minima inside the largest peak, giving up to 8 candidate thresholds to choose from — useful for quickly comparing where different cutoffs land without re-running the graph. ## Installation ### Via ComfyUI Manager (recommended) Search for **"easygoing"** in Nodes Manager and install.

### Manual After enabling the ComfyUI Python virtual environment: ```bash cd ComfyUI/custom_nodes git clone https://github.com/easygoing0114/ComfyUI-AutoMask.git cd ComfyUI-AutoMask pip install -r requirements.txt ``` ## Requirements - `opencv-python` - `pymatting` ## Credits - **Mask Refine** is a simplified reimplementation of the **Image Matting** node from [ComfyUI-Image-Filters](https://github.com/spacepxl/ComfyUI-Image-Filters) by [spacepxl](https://github.com/spacepxl). ## License - [MIT](LICENSE)

Name	Type	Default	Description
image	IMAGE		—
mask	MASK		—
preblur	INT	100–256	—

Mask Refine

Inputs (3)

Outputs (1)