How to use im2warp with displacement field

A manual of im2warp function says that

B = imwarp(A,D) transforms the input image A according to the displacement field defined by D.

So my goal is to warp A define dy

 A = [1 0 0 0;0 0 0 0;0 0 0 0; 0 0 0 0];

The displacement is given by

 uu = zeros(4,4,2);
 uu(1,1,1) = 3;
 uu(1,1,2) = 1;

I use the function

 imwarp(A,uu,'nearest')

My expected result is

 A_res = [0 0 0 0;0 0 0 0;0 0 0 0; 0 0 0 1];

However, the result is

>> imwarp(A,uu,'nearest')

ans =

     0     0     0     0
     0     0     0     0
     0     0     0     0
     0     0     0     0

How to use imwarp with displacement?

Answer 1

[Image Analyst]

Use imtranslate() - it's easier.

[jakeoung koo]

Actually, my goal is to warp original region to another region. (Given by a displacement through optical flow estimation)

Even if I can translate a region, the warped region is very sparse. Although I use interpolation function, it doesn't work because in the outside of region, there is no displacement.

[Image Analyst]

You're going to have to figure out how to warp the one arbitrarily-shaped region from image #1 into another arbitrarily-shaped region like in image #2. This might apply to the whole image but you're going to have to mask it to replace the pixels you didn't want to warp with the original pixels.

[jakeoung koo]

I just want to warp binary image representing the region in question. I have lost how to warp the binary region given a displacement defined only within region.

I tried using singed distance function, but it also doesn't work.

Thanks for your comment. I will think about it.