Detect the `Shaded Region` and Remove it [closed]

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Hi,

I have a diagram like these:

I would like to detect the region which is shaded. Obviously, the shaded region is not really shaded, it just consists of a dense array of lines. I am also makeing a line tracing algorithm to detect the real lines, but these shaded lines distract my algorithm , so I need to remove them.

How do I detect the shaded regions and remove them?

Thanks a lot!