Inquery of Fig.3 in paper

[Nyquist0]

Dear Sir or Madam,

I would like to consult you about how to get the heat map in Fig.3 in your published paper.
Because I found the sep_backgound image generated consists of both margin of head and background. But the figure shows that only consist of body area except for face.

So I am confused about the difference. Could you please help to clarify it?

Looking forward to your reply. Best.