Is there a function for remapping of hue color or desaturating the hue? please help

I need to fuse two images and to retain the natural color of the visual image i need operate the fused image such that it retains its natural color.

[Guillaume]

You need to be a lot clearer about what you want. An example of inputs and desired output would greatly help.

imfuse, assuming that's what you mean by fuse has several fusing methods. Which one are you talking about?

What is your definition of natural color?

Which of the two image should retain its natural colour?