Measurement of Perceived Objects

We describe an experimental prototype system in which a virtual protractor is used to measure three dimensional relationships between objects. The objects being measured are not modeled explicitly using surface or procedural geometric definitions in the traditional sense, but rather are perceived by a viewer who looks at stereo image pairs. In contrast, the virtual instrument itself is represented using traditional geometric models. A stereo imaging model that is consistent across image-based and geometric-based model viewing is required for successful stereo perception (fusion) and belief that geometry and image-based objects are part of the same scene. Control of inter-image registration as well as placement of geometry are the independent variables of the system. The qualitative lessons from this experiment lead us to conclude that stereo imaging combined with motion parallax allow a researcher to measure three dimensional relationships in data acquired from an electron microscope.