foreground linearts

I wish to separate the drawing of a background or separate the drawing in parts
but extract foreground and background is not good with linearts

2018-06-28-173936_473x612_scrot

Some idea?

Select by alpha?

no. select Intelligently using line or similar

2018-06-28-181908_402x519_scrot
↑ original image

I can not see my old PSD, asi that thought to re-create project in gimp separating the layers

Depending on the version of PS the file came from, GIMP might be able to open it with layers.

The project is old and the idea to separate by lineas likes me.
I can use this to invent new layers and use this for other drawings or create animations

The result that wish is something like this