How can I interpolation values within a 3D matrix by ignoring zeros?

I have a 3-D matrix, many values of which are zero but some of which have non-zero values in them.

I'd like to fill in the zeros by 'interpolating' or filling in based on the non-zero values. I don't want the zeros to go into the calculation of the interpolation, only the non-zero values, and these values should replace the non-zero values.

Answer 1

[Kelly Kearney]

I use this function a lot: inpaint_nans3. If x is your 3D matrix:

x(x == 0) = NaN;
newx = inpaint_nans3(x);

Answer 2

[Image Analyst]

If you have the Image Processing Toolbox, use roifill(). Create your binaryImage like this:

binaryImage = image3D == 0;

Then fill

filledImage = roifill(image3d, binaryImage);

[Ajay]

This solution produces an error. Maybe the function does not handle 3D matrices?

>> filledImage = roifill(image3D, binaryImage); Error using roifill Expected input number 1, I, to be two-dimensional.

Error in roifill>ParseInputs (line 242) validateattributes(I, {'uint8', 'uint16', 'int16', 'single', 'double'}, ...

Error in roifill (line 78) [xdata,ydata,I,xi,yi,mask,newFig,placement_cancelled] = ParseInputs(varargin{:});

[Image Analyst]

The documentation didn't say that it was limited to 3D images, but maybe it is. In that case there's no built in method and you'll have to write your own.