One can only help if you can provide some clear information
Try to answer the following
How do you import the data in Matlab ?
Is it slices of images stacked or simply co-ordinates of points ?
What do you mean when you have the co-ordinate points are they
relative to a cartesian co-ordinate system.
> I trying to work with 3d images, and I need to calculate the
> coordinates of a point (I know its position on the images and of
> course, the camera parameters). what can I do?? how can I calculate
> the global coordinates of a pixel??
> please help me!!!