Creating a depth map of a 3D surface

I want to create a depth map of a 3D object (ie some 3D object like a sphere or cube plotted with surf or mesh) from an arbitrary perspective. I could write a primary ray-tracing algorithm but this seems like a lot of overhead. Is there any pre existing function to do something like this?

Answer 1

[George Abrahams]

Hi @Ben. My 3D Rendering Toolbox on File Exchange will easily handle this, assuming that you want a perspective projection. For example, you can see the toolbox generating a depth map in the figure below.

[Mohannad]

Hi, prof. @George Abrahams

Could you please guide me on how to replace PROJECTION_MATRIX with a camera Intrinsics (K)?

[George Abrahams]

Hi @Mohannad. I've just published an update to the ProjectionMatrix class to convert an intrinsic matrix to a projection matrix, which is required to perform rendering with the toolbox. The syntax is:

obj = ProjectionMatrix(intrinsicMatrix, imageSize, near, far)

As with everything else, there's detailed documentation about the inputs and so on in the code.

Answer 2

[Walter Roberson]

Would this be like projecting perpendicular to the perspective and then taking the point by point max() of the resulting z values?