How to get the initial displacement field?

[username123062]

Thanks for your attention! I am confused about the initial displacement field.

In the Figure 5 of your paper, the "center" image is an initial displacement field. What is meaning of different colors about it? And how we get it? Does it has any relationship with the CAM of the corresponding image?

Looking forward to your reply.

[username123062]

Also, can you explain "why the background is from white to violet" in the fig.5 of your paper.