Verify positions of other model points, edges, or faces. You can now do this!
LOTS of work in the literature on this! Can work for many industrial objects (and human faces perhaps!)
Triangular meshes Very general and used by most CAD systems.
Texture-mapped mesh dog Courtesy of Kari Puli With each triangle is a mapping of its vertices into pixels [r, c] of a color image. Thus any point of any triangle can be assigned a color [R, G, B]. There may be several images available to create these mappings. 3D SURFACE MODEL SURFACE PLUS TEXTURE
Meshes are very general They are usually verbose and often are too detailed for many operations, but are often used in CAD. (Volumetric cube models are actually displayed here: made from many views by Kari Pulli.)
Modeling the human body for clothing industry and … Multiple Structured light scanners used: could this be a service industry such as Kinkos? Actually cross sections of a generalized cylinder model.
Mesh characteristics + can be easy to generate from scanned data
Marching cubes http://www.exaflop.org/docs/marchcubes/ (James Sharman) "Marching Cubes: A High Resolution 3D Surface Construction Algorithm", William E. Lorensen and Harvey E. Cline, Computer Graphics (Proceedings of SIGGRAPH '87), Vol. 21, No. 4, pp. 163-169. Raster scan through image F(r, c). Look for adjacent pixels, one above threshold and one below threshold. Interpolate real coordinates for f(x, y) = t in between
Marching in 3D space F(s, r, c) Some voxel corners are above threshold t and some are below.
Scanning technique abstraction CCD camera (row) material sample X-ray planes scintillator Pin head rotate X-rays partly absorbed by sample; excite scintillator producing one row in the camera image; rotate sample a few degrees and produce another row; 3D reconstruction using CT
hard CS part is detecting when balloon should be stopped by data point
Physics-based models Can also model dynamic behavior of solids (Finite Element Methods)
Tagged MRI: 3D interest points can be written to body! The MRI sensor tags living tissue and can sense its movement. Motion of a 3D tetrahedral finite elements model can then be analyzed. FMA model attempts to model the real physics of the heart. Work by Jinah Park and Dimitry Metaxes.
Algorithms from computer graphics make mesh models from blobs
Marching squares applied to some connected image region (blob)
Marching cubes applied to some connected set of voxels (blob)
See a CG text for algorithms: see the visualization toolkit for software
View class model of chair 2D Graph-matching (as in Ch 11) used to evaluate match.
Side view classes of Ford Taurus (Chen and Stockman) These were made in the PRIP Lab from a scale model. Viewpoints in between can be generated from x and y curvature stored on boundary. Viewpoints matched to real image boundaries via optimization.
Matching image edges to model limbs Could recognize car model at stoplight or gate or in car wash.
Appearance-based models Using a basis of sub images; Using PCA to compress bases; Eigenfaces ( see older .pdf slides 14C)
Function-based modeling Object-oriented; What parts does the object have; What behaviors does it have; What can be done with it? (See plastic slides of Louise Starks’s work.)