Skip to main content
Mask Cleanup (ComfyTV)

Mask Cleanup (ComfyTV) · screenshot coming soon

​
What this node does

Mask Cleanup takes a native ComfyUI MASK and tidies it up: it deletes tiny disconnected islands (little white blobs floating away from your subject) and fills small holes (little black pinholes inside a solid area). It keeps the largest region intact and only removes/fills things that are smaller than a size threshold you set. This is a plain, instant CPU operation (it uses scipy connected-component labeling) — there is no ▶ Run or GPU pass. Because it works on the native ComfyUI MASK type, it usually sits between a mask-producing node (a matte, a segmentation, a threshold) and a mask-consuming node, often reached through a Bridge (bridges docs).

​
When to use it

  • After chroma keying or background removal, when the alpha has confetti-like specks around the edges.
  • After a segmentation/matte model that leaves pinholes inside a solid subject.
  • Before inpainting or compositing, when you want one clean blob instead of a noisy binary mask.

​
Parameters

​
min_region_frac

Float, default 0.01, range 0.0–0.2, step 0.001. Islands and holes smaller than this fraction of the mask’s largest region are removed (islands) or filled (holes). At 0.01, anything under 1% of the main blob’s area is cleaned up. Raise it to be more aggressive (remove larger stray bits); lower it to touch only the tiniest noise. There is an absolute floor of 64 px, so very small regions are always eligible for cleanup even at 0.0. The largest region is never removed, and holes that touch the image border are left open (they are treated as background, not enclosed holes).

​
Outputs

​
Tips

  • The mask is thresholded at 0.5 internally, so the output is effectively binary (hard 0/1) — soft/feathered gradients are not preserved. Feather or blur after cleanup if you need soft edges.
  • If scipy is not installed, the node logs a warning and passes the mask through unchanged.
  • Border-touching black regions are intentionally kept open, so a hole that opens onto the edge of the frame will not be filled.
  • Cutout — produces a subject cutout whose alpha you may want to clean first.
  • Bridge (to/from Mask) — convert between ComfyTV media and the native MASK this node consumes.