anyone would like to share how to carve nfl helmet, can it be done on easel or vcarve?
In what way do you mean? Profile or full bodied? Carving onto a pre-existing helmet?
Need more input 
In general, anything is possible but whats the best workflow is more dictated by desired outcome.
That is very doable.
In Easel you basically import the artwork and NFL-image, do an Image Trace (app) + Offset app for the outline.
You need to split the image into two objects so you can treat them individually, otherwise it will all be carved to same depth.
Copy image, use the Xploder-app to break it up then delete the unwanted parts.
