[Feature]: Add Alpha Matting

[SpenserCai]

Expected behavior

Hope to migrate the Alpha Matting from Rembg.

This feature is already well used in stable-diffusion-webui-rembg

Not use Alpha Matting

Use Alpha Matting

[continue-revolution]

What's the difference?

[SpenserCai]

When not in use, there will be obvious white edges. After use, there will be no white edges (you can clearly see this from the head of the figure in the picture). The role of alpha matting is to add transparent blur as a transition. It has a good optimization effect for very delicate objects such as Tennis racquet , hair.

[SpenserCai]

so in Rembg has alpha matting and stable-diffusion-webui-rembg also implemented it