Let's take a step back from defining a specific type of imaging technology and look at the problem a little more closely to see which imaging technology might be best suited to fit this problem.

The idea is that you want to know the complex 3D surface of an appendage that is organic so that this can be mapped. Once this is a known surface, a force per unit area is applied so that the appendage deflects. The deflection needs to be a measured so that different areas of the appendage can be assessed for generation of a prosthesis.

This problem can be done through a volumetric examination, but I believe that would be overkill. Volumetric examinations would include ultrasound, CT, or MRI, for example. Ultrasound would be the most practical to get the 3D surface trhough an immersion technique. Surface imaging would be a lot cleaner solution. Surface imaging techniques would involve a 3D laser scanner or machine vision.

Probes could be made with a spring that followed a K constant and the probe could also have a linear potentiometer to measure resistance to know the deflection, but the probe may not have to include the resistance if the surface scanner can also see the deflection in the probes.

Once the data is collected, the biggest problem is what to do with the data. The most complex way of handling the data that will give the most desireable results will involve reversing a Finite Element Analysis. With FEA most people want to see what the deflection is based on material properties and force applied. In this case, you know the deflection and force properties, but lack the material propeties. Pseudo material properties may be able to be solved that allow a perfect fit.

A less complex method would be to take multiple data points involving different pressures and then plotting the deflection in a 3D with a color map.

How a prosthesis is born utilizing this information is ouside my realm.

Just my two cents.